航空知识

RQ-170 无人驾驶偵查機

2011-12-06T23:25:00.002+08:00

Lockheed Martin RQ-170 Sentinel

The RQ-170 Sentinel is an unmanned aerial vehicle (UAV) developed by Lockheed Martin and operated by the United States Air Force (USAF). It has been deployed to Afghanistan as part of Operation Enduring Freedom.

RQ-170 哨兵是由洛克希德·马丁公司研制的一种主要用于对特定目标进行侦查和监视的隐形无人机，也被称作“坎大哈野兽”。它曾在持久自由行动中被部署在阿富汗境内，有消息称它也将被部署在韩国。

研发
2001年EP-3E侦察机在中美撞机事件之后在中国迫降，致使美国国防部下决心研发一种隐形无人机，以避免涉密装备和机组成员落入其他国家。RQ-170正是在这种背景下诞生的，它由洛克希德·马丁著名的臭鼬工厂设计，与之前的一些隐形无人机，如RQ-3暗星，在设计上有相似之处。采用无尾飞翼的气动设计，搭载一台涡扇发动机作为动力。据估计，RQ-170的翼展在20米左右。代号中的“RQ”意味着RQ-170是一种不携带武器的无人机，是第一种被证实承认的采用隐身设计的无人机。

部署2009年12月4日，美国空军首次证实了RQ-170的存在。持久自由行动中，RQ-170被部署在阿富汗境内。由于2007年年底在阿富汗南部坎大哈国际机场露面，它获得了“坎大哈野兽”的外号。值得注意的是，在阿富汗的塔利班武装目前既没有防空导弹，也没有雷达，所以RQ-170的隐性性能对于阿富汗战场并没有多大意义，RQ-170在阿富汗的部署很可能是针对中国。另有消息称RQ-170将被部署在韩国，以便对朝鲜进行监视。

01-10-11

2011-10-01T20:06:00.005+08:00

01-10-11

2011-10-01T20:06:00.003+08:00

01-10-11

2011-10-01T20:06:00.001+08:00

NASA Prepares 'Global Hawk' for Takeoff

2010-03-31T23:45:00.003+08:00

NASA is gearing up Global Hawk, a remote-controlled airplane, for its first scientific flights in coming weeks. With its capacity for long-distance, high-altitude flights that can last over a day, Global Hawk presents a new chapter in Earth science for NASA.

"It's a very exciting time," said Chris Naftel, project manager for Global Hawk. "This is the very first time that Global Hawk will be used for science.

"Northrop Grumman originally manufactured the two Global Hawks now being retrofitted by NASA several years ago. These remote-controlled airplanes can fly for about 30 hours at altitudes up to 65,000 feet and were designed initially as surveillance aircraft.

The maiden voyage over the Pacific Ocean will be followed by several other jaunts into the Arctic regions to learn more about Earth's atmosphere. One day, Global Hawks might provide real-time data from the heart of hurricanes and other major storms that are far too dangerous to risk sending in manned aircraft.

Loading the payload

Over the last couple of weeks, engineers, scientists, and aviation technicians at the Dryden Flight Research Center at Edwards Air Base in California have been mounting equipment-from high-definition cameras to ozone sensors-onto a Global Hawk.

The craft measures 44 feet (13 meters) in length with a wingspan of 116 feet (35 meters). NASA expects to operate the Global Hawk with payloads up to 2,000 pounds (907 kilograms).

The long wings carry the plane's fuel, and the bulbous nose is one of the craft's payload bays, which house the science instruments.

After a full test run with a dozen scientific instruments later this week or early next week, the first science flight will commence by mid-April, Naftel said.

The science run will be the first of four or five as part of the Global Hawk Pacific campaign, or GloPac for short. The robotic aircraft's instruments will sample the chemical composition of air in Earth's lower atmospheric layers as well as observe clouds and the sea below.

The primary purpose of the GloPac mission will be to check the accuracy of NASA's Aura satellite, which measures ozone, air quality, and climate data. The Global Hawk will fly underneath the orbiting satellite and collect data simultaneously to see if its data matches that of the satellite.

The sky is the limit

Another major goal of the early runs will be to figure out just what else is possible with the Global Hawk. "We want to know, 'how do you use this platform for research?'" Naftel said.

The ideas may come from beyond NASA: Dryden will soon have live feeds from the Global Hawk, including high-definition ocean snapshots that "should be really fascinating for the public to see," Naftel added.

17-12-2009 Boeing Dreamliner 787 takes its maiden flight

2009-12-17T16:39:00.002+08:00

By Dan Reed, USA TODAY

The future of commercial aviation arrived Tuesday — albeit 28 months late — when Boeing's 787 Dreamliner took off from Paine Field in Everett, Wash., just before 10:30 a.m. on its maiden flight.

The Dreamliner, whose test flight was repeatedly postponed, won't enter commercial service until late next year at the earliest. And that's only if everything goes perfectly during what promises to be the most rigorous flight-testing and certification program in commercial aviation history.

The Dreamliner is the first commercial aircraft to be made mostly from composites rather than conventional aluminum and steel.

Aviation analyst Richard Aboulafia, of The Teal Group, says certification should take at least 12 months. Then, he says, Boeing must get production volumes up and "improve the plane so that it comes close to being the plane that it was promised to be." That, he says, "may take them 200 or so planes to do."

Another analyst, Jon Ostrower, who has tracked the 787's star-crossed development, says the six delays that pushed back the Dreamliner's first flight more than two years did produce a benefit: more opportunity to work out bugs in advanced systems on the plane that flew Tuesday.

"Now this is when the hard part really begins," he says. "Boeing has the opportunity to take what was the symbol of their struggles — this plane sitting on the ground — and give it the chance to prove itself. It allows Boeing to start on the road back to restoring their credibility."
Befitting its nickname, the Dreamliner is arguably the most anticipated new commercial plane.
At one point, Boeing had nearly 940 orders for 787s. But the delays and tough economic conditions caused airlines to cancel at least 83 orders this year alone. At present, airlines have more than 840 firm orders in place for 787s.

Airlines desire the 787 because it promises to cut the cost of flying long-range routes by 15% to 20%. Reduced weight, advanced design and more efficient engines from General Electric and Rolls-Royce make those savings possible over long distances, where the fuel savings can add up.
Consumers also are expected to benefit from the 787's wider and taller fuselage and its advanced environmental control systems, which Boeing officials claim will make the 787 the world's most comfortable plane.

The 787 offers passengers the prospect of more overhead baggage space. And it will have larger windows than current jetliners because the structural integrity of its hull won't be compromised by larger windows, as would be the case on conventional metal planes. Boeing also has added a nifty creature comfort to the larger windows: electric shades that roll up or down at the touch of a button.

Su-35BM 飞行小意外

2009-10-01T00:54:00.008+08:00

图片是2009年8月22日周六在航展上苏-35飞行资料图。

在俄第九届国际航空航天展览会上，俄最新歼击机苏-35BM差点因降落事故而报销。

俄媒8月26日报道说，MAKS-2009航展上发生的事故仅仅是之前“俄罗斯勇士”飞行表演队在彩排时发生的飞机相撞事故，还有一个事故也差点发生。

俄最新歼击机苏-35BM在降落时向右倾斜，其机翼离跑道仅几厘米之差几乎触地。俄航空专家表示，在这样的速度下如果飞机机翼触地，其后果是下一秒飞机就会嘴“啃”地、侧翻然后四分五裂。

有参观者还误以为是俄新式战机在进行特技表演。照片清楚显示，飞机降落时发生倾斜，靠右侧起落架落地。

国庆60周年阅兵空中梯队受阅过程详解

2009-09-30T21:25:00.002+08:00

在国庆60周年阅兵中,空中梯队将飞越天安门广场,持续时间9分20秒。空中梯队如何完成受阅,新华社记者为您详解全过程。

在7个军用机场起降

受阅飞机分别从南苑等7个军用机场起降。如果遇到极端天气,空中梯队还在北京周边准备了若干备用机场。

阅兵空中基准航线106公里

这次阅兵,空中梯队基准航线为一条直线,东起河北螺山火车站,向西经纪各庄、通州、天安门至公主坟,共106公里。

不同方式加入基准航线

空中12个梯队依次进入基准航线,并排列成一条直线,由东至西飞越天安门广场。但由于受阅的15种机型分驻在不同机场,而且速度大小不一,因此各梯队飞机起飞的顺序、时间都经过了周密计算。

受阅时,直升机梯队由通州上空加入基准航线,其余各梯队分别由螺山火车站、纪各庄加入基准航线。

作为领队梯队长机的空警-2000将最先起飞。

由单一机型组成的梯队,如轰炸机、歼击轰炸机、歼击机、直升机和教练机梯队,各驻在同一机场,它们起飞后即编队飞行,按规定高度、时间在规定地点加入基准航线。

多机型的混合编队,如领队梯队、预警机梯队、加受油机梯队,不驻在同一机场,大飞机先飞至小飞机所在机场,等候小飞机起飞后编队,再按规定高度、时间在规定地点加入基准航线。

直升机梯队飞行高度低、速度慢、飞行距离近,加入基准航线后其他梯队要从直升机梯队上方超越。

梯队顺序体现空中作战体系

空中梯队大体按预警机、对地突击飞机、制空作战飞机、直升机、教练机的顺序排序,体现攻防兼备的空中作战体系。

通过位置点为人民英雄纪念碑上空

受阅时,空中梯队通过天安门广场的位置点为人民英雄纪念碑上空,距天安门城楼水平距离450米。

从第一架领队梯队长机——空警-2000通过人民英雄纪念碑上空,到最后1个梯队教8飞机通过人民英雄纪念碑上空,持续时间9分20秒。

各受阅梯队中,直升机梯队通过天安门广场时高度最低,为250米,其余梯队高度在250米至600米之间。

2个梯队拉烟通过天安门广场

受阅时,第一个通过天安门广场的领队梯队中的8架歼-7GB护卫机,将拉出彩色烟雾。最后一个通过天安门广场的教练机梯队的最后1个5机楔队,也将拉烟。

各梯队前后间隔一般40秒

受阅时,各梯队前后间隔一般40秒,最小20秒。梯队中的各编队间隔只有5秒。

空中梯队总长75公里。

大部分飞机间隔距离在15至20米

受阅时,大部分编队内飞机间隔距离在15至20米左右。

值得一提的是,在加受油梯队中,空军2架轰油-6将分别与空军2架歼-10、2架歼-8D组成2个加受油楔队,模拟空中加受油状态飞越天安门广场。它们之间的间隔距离是空中梯队中最小的——受油机距加油机加油锥套只有2米。

受阅要求:米秒不差

在通过人民英雄纪念碑上空时,空中梯队要求各编队队形的间隔距离误差在1米之内,到达时间与规定时间误差在1秒之内,这已超过了现行训练大纲的规定。

作战飞机挂弹受阅

这次阅兵中,空中梯队所有作战飞机都将挂弹受阅,多型空空、空地导弹首次公开亮相。

这将是空中梯队在历次国庆阅兵中第二次挂弹受阅,第一次是1949年的开国大典。

为了保证安全,空中梯队已拆除所有挂载导弹的战斗部和引信;没有接通导弹与飞机上的电源;挂弹飞机在飞行中一律关闭武器控制电门;采取特殊措施加固导弹与挂架的连接,防止飞行中导弹掉落。

空中梯队分别在复兴门、公主坟上空解散

飞越天安门广场上空后,直升机梯队在复兴门上空解散,其余各梯队在公主坟上空解散,返回各机场。

来源:新华网

第七代雷鸟照片

2009-09-30T20:28:00.004+08:00

General Dynamics/Lockheed Martin F-16 Fighting Falcon 1982~Current

第六代雷鸟照片

2009-09-30T19:51:00.004+08:00

Northrop T-38 Talon 1974-1981

第五代雷鸟照片

2009-09-30T19:41:00.002+08:00

McDonnell-Douglas F-4E Phantom II 1969-1073

第四代雷鸟照片

2009-09-30T19:33:00.002+08:00

Republic F-105 Thunderchief 1964

第三代雷鸟照片

2009-09-30T18:05:00.004+08:00

North American F-100C Super Sabre 1956-1963

North American F-100D Super Sabre 1964-1968

第二代雷鸟照片

2009-09-30T18:01:00.005+08:00

Republic F-84F Thunderstreak 1955

第一代雷鸟照片

2009-09-30T17:52:00.006+08:00

Republic F-84G Thunderjet 1953-1954

Thunderbirds 雷鸟飞行表演队

2009-09-30T17:47:00.001+08:00

美国空军---雷鸟飞行表演中队

“雷鸟”表演队全称“美国空军飞行表演中队”(USAF Demonstration Squadron)，现驻内华达州内利斯空军基地，使用9架F-16C“战隼”战斗机和3架F-16D双座教练型，表演时采用6机编队。

“雷鸟”表演队于1953年5月25日在亚利桑那州卢克空军基地组建，仅两周后就开始表演，至今已半个世纪。“雷鸟”的命名部分是受卢克空军基地所在的美国西南部较浓厚的印第安文化影响，“雷鸟”据说是一种神鸟，当它腾空而起时，大地也会在它的巨翼扇起的雷鸣中颤抖，眼中还会发出闪电。

刚组建时，该表演队称为第3600飞行表演部队，共7名军官和22名士兵，主要来自卢克基地，首任队长迪克·卡特利奇少校。有趣的是，左右翼的僚机分别由一对双胞胎上尉担任。表演队的宗旨是作为“蓝天大使”，帮助空军征兵，向公众展示空军人员的职业化水平和当时刚刚出现的高性能喷气式飞机的力量，后一点并不只是为了表演，因为朝鲜战争中喷气式飞机才刚投入实战，需要让公众信任这种新技术。

该表演队装备的第一种喷气式飞机是共和航空公司的F-84G“雷电喷气”(Thunderjet)，这种亚音速平直翼战斗轰炸机经历了朝鲜战争的实战检验。1955年初，“雷鸟”换装了后掠翼的F-84F“电闪”(Thunderstreak)，并已经开始到中美洲和南美洲国家表演，还开始采用拉烟技术。在使用F-84的3年中，“雷鸟”就表演了222场，观众900万以上。

北美公司的F-100“超佩刀”是第一种超音速喷气战斗机，1956年成为“雷鸟”的第3种机型，这也使它成为世界上第一支使用超音速喷气战斗机的表演队。这一年该中队迁至现在的内利斯基地，编入第57联队。这一时期，虽然不属例行表演课目，“雷鸟”有时也应表演组织者的要求在单机表演时进行超音速飞行，但联邦航空机构很快禁止在任何航空表演中超音速飞行。

1964年，“雷鸟”还短暂地使用过F-105B“雷公”(Thunderchief)战斗机，只在4月26日到5月9日间进行了6场表演，就改为可以空中加油的F-100D。使用F-100的13年是令人难忘的，“雷鸟”共使用F-100C和D型表演1100场以上，并首次出现在远东、欧洲和北非的天空。

1969年，“雷鸟”换装了F-4E“鬼怪”II，这是越战时期的主力战斗机，也是第一种和唯一的一种被“雷鸟”和“蓝天使”同时采用的机型。F-4E是“雷鸟”最震撼的机型，四机编队的F-4E有8台J-79发动机，声如雷鸣。5年间，F-4E共表演500场以上，到过美国的30个州，以及加拿大、中美洲和欧洲。

但由于1974年石油危机来临，“雷鸟”改用了世界上第一种超音速喷气教练机——T-38A“禽爪”(Talon)，该机省油(5架的耗油量才相当于一架F-4)，维护成本低，一直使用了8年，表演近600场。在1976年美国建国200周年庆典中，该机型还为华盛顿特区的国家航空航天博物馆开馆仪式助兴。

1983年初，“雷鸟”换装了F-16A战斗机，又回到了使用前线战斗机的时代，换装的头一个表演季节，全美就有33个州的1650万观众目睹了美国最新战斗机技术的展示。1987年，“雷鸟”在进行远东巡回表演时，曾在中国北京的南苑机场进行了表演，这是美国的表演队首次出现在社会主义国家。

1992年又换成了F-16A的改进型F-16C，它是最后一个换装C型的F-16中队。1994年，“雷鸟”进入了第5个十年，这一年表演67场，观众600万，使累计观众总数超过了2.75亿。1996年，“雷鸟”首次出现在东欧国家，对罗马尼亚、斯洛文尼亚、保加利亚等9国进行了访问，回国后又参加了亚特兰大奥运会的开幕式。11月10日,“雷鸟”用F-16的飞行表演达到了1000场。

至今，“雷鸟”表演队已在美国50个州和世界60个国家表演，成为历史上周游世界各地最多的表演队，1999年累计观众就突破了3.15亿。

当前，“雷鸟”表演队隶属空军空战司令部，任务是：支援美国空军征兵，促进军人续签服役合同；增强空军全军的信心，向公众展示空军人员优良的职业素质；鼓舞空军士气和团队精神，改善空军团队关系；向外国展示美国及其武装力量的形象和良好意愿。

“雷鸟”全队共有8名飞行员(其中6名表演飞行员)、115名士兵、4名支援军官和4名文职人员，有27个不同岗位，一般包括10%-15%的女性，2003年有8人。军官在该中队服役时间为2年，士兵3-4年，每年更新近1/3的人员。飞行员至少要有1000小时军用喷气飞机驾驶经验，每年从申请人中选出4-5人面试，竞争3个名额，入选后要完成120架次训练飞行。地勤人员每年有4个新名额，训练需要21天。

在3500多场次正式空中表演中，“雷鸟”没有一次因为飞机机械故障而停止表演。最早的表演包括持续15分钟的一系列编队特技。起初，备份机会提前起飞，观察天气、周围空域有无越界飞行器和障碍等情况后降落，继续担任备份。后来这一机会被用作单机表演。早期的表演季节很短，1974年时只有4个月，这一年“雷鸟”共表演35场，今天的表演季节已经发展到从每年3月到11月，一共要表演88场，每次表演有30个机动动作，包括编队飞行和单机表演，整个表演从地面算起历时1小时15分钟。

“雷鸟”现有的F-16改动很小，只拆除了雷达、内置20毫米机炮和弹鼓，改装了发烟系统，油门杆上的格斗开关换成拉烟开关，并增加一个秒表。但表演专用设备不断改进，比如现在的拉烟器是向飞机喷管中喷入一种石蜡油，遇到高温喷流立即汽化，形成烟迹。

“雷鸟”的表演对天气要求较高，从表演中心看去水平能见度9.26千米，云底高至少457米时，也只能进行基本表演；云底高1067米时可进行一般表演，包括一些滚转机动；云底高2438米时才能进行全部动作的表演。

“雷鸟”平均每年在北美40个地点表演70场，表演季节内几乎每个周末都有表演。一般周四到达表演场地，前一天到达的先遣飞行员通报当地情况。周五一般是预演，熟悉地形地标，试飞后还要安排一些会见、参观等公关活动。周六正式表演，同时要安排一些入伍和续签合同仪式，媒体见面会等活动。在每个表演地，“雷鸟”还可以安排两名当地媒体的记者乘F-16D双座机进行体验飞行，每年还安排一些电视台和体育、音乐、电影界的人员体验飞行，目的是促进宣传报道，树立良好形象。

Virgin Galactic Rolls Out Mother Ship

2009-07-29T09:21:00.008+08:00

Virgin Group head Sir Richard Branson unveiled the latest addition to his air- and spaceline fleet at the Mojave Airport in California today, accompanied by the craft's chief designer, Burt Rutan.

The White Knight 2 is a four-engine jet that will carry an 8-seat spaceship called SpaceShipTwo to an altitude of 48,000 feet so that the spaceship can drop off and fire its rocket engine for a brief run to suborbital space. Branson's Virgin Galactic hopes to begin regularly scheduled passenger service to space in 2010.

Rutan's company Scaled Composites made history in 2004 with the world's first privately funded manned spaceflights by its three-seat SpaceShipOne, which was carried aloft by the original White Knight. The White Knight 2 features two fuselages, each with its own cabin, connected by a single continuous wing arching between them, where the spaceship will ride. With the wing span of a B-29 bomber, it is the largest all-carbon-fiber aircraft yet built.

On hand to christen the White Knight Two outside a Scaled hangar was Branson's mother, Eve. Not coincidentally, Eve is also the name of the mother ship. "If you're going to name a mother ship," Branson quipped to a gathering of perhaps two hundred reporters and dignitaries, including Apollo 11 moonwalker Buzz Aldrin, "you might as well name it after your own mother."

Eve Branson stood with her son beside the White Knight 2 as Sir Richard shook a bottle of Champagne and then hosed down a gaggle of reporters photographing the event as he opened it. When asked how she felt having an exotic new aircraft named after her, Eve replied, "I don't know what to say. But am I allowed to drink this?"

Kidding aside, Branson has serious aspirations for the White Knight 2. Besides carrying paying passengers to space, 270 of whom have ponied up $200,000 each for tickets or put down substantial deposits, Branson envisions White Knight 2 ferrying government, industrial, and academic researchers and their experiments into the realm of weightless flight on a regular basis. Future craft using the White Knight 2/SpaceShipTwo technology could also enable superfast travel from one point on the Earth to another.

The White Knight 2 will begin ground testing tomorrow, with flight testing expected to begin in the fall. SpaceShipTwo is still under construction, with flight testing pending the conclusion of an investigation into the causes of a test stand explosion that claimed the lives of three Scaled employees last summer.

Virgin Galactic president Will Whitehorn said today that the spaceship would not fly passengers until it was absolutely safe to do so. "Safety is our north star," he said. "Safety is crucial to us because Virgin is invested in four airlines, including Virgin America, in four continents.... Our name has become a byword for safety and innovative and efficient transportation solutions."

That's a hard-won reputation the hugely profitable group of companies won't willingly squander.

Senate votes to stop production of F-22 jet

2009-07-22T23:44:00.001+08:00

WASHINGTON (Reuters) – The U.S. Senate voted on Tuesday to stop production of the F-22 fighter plane, handing President Barack Obama a victory as he tries to rein in defense spending.
The Senate voted 58 to 40 to strip $1.75 billion for the Lockheed Martin Corp-built planes from a $680 billion defense bill, overriding the objections of lawmakers seeking to protect manufacturing jobs in the midst of a deep recession.

The Senate's vote does not necessarily kill the program, as the House of Representatives included funding for the state-of-the-art fighter in its bill, which sets military spending priorities.
The two chambers must resolve their differences before sending a final bill to the president to sign into law.

Obama has threatened a veto if Congress continues to fund the F-22 beyond the 187 planes already built or in the production pipeline.

"At a time when we're fighting two wars and facing a serious deficit, this would have been an inexcusable waste of money," Obama said after the vote.

Defense Secretary Robert Gates has proposed capping production as part of an overhaul of the Pentagon's weapons programs as it tries to provide resources to fight insurgencies like those in Iraq and Afghanistan. The Pentagon applauded the vote.

Later on Tuesday the Senate voted 93-1 to extend the authorized end strength of the U.S. Army by 30,000 troops over the next three years starting October 1.

The amendment, by Sen. Joseph Lieberman, does not mandate the increase, but provides the authority for Defense Secretary Robert Gates to carry out his plan for a temporary increase of 22,000 in the Army's size and go further if he needs to, a Senate staffer said. The House has passed similar language.

In a separate voice vote, the Senate also adopted a measure that urges Obama to impose sanctions on Iran's central bank if that country continues to pursue its nuclear program and rejects an offer for diplomatic talks.

The radar-evading F-22 is designed for combat against other fighter jets but has not seen action in the Iraq or Afghanistan conflicts, where U.S. foes have not fielded an air force. Critics point out that each hour of flight time requires 30 hours of maintenance and say the plane is a relic of Cold War military strategy.

The Pentagon wants instead to ramp up production of the cheaper, more versatile F-35 Joint Strike Fighter, and Gates said last week that funding for that program could be jeopardized if Congress continues to fund the F-22.

Lockheed Martin is the primary contractor for both planes. The company's stock closed at $75.13, down 8.5 percent, on a day when it posted better-than-expected quarterly earnings but failed to raise its full-year forecast.

F-22 backers in the Senate said national security could be compromised if the plane was canceled. Up to 95,000 jobs across the country also could be at risk, said Democratic Senator Chris Dodd of Connecticut, a hub of defense manufacturing.

"To give up an aircraft of this sophistication and this capability, and simultaneously in an economic situation such as we're in .... I think is terribly shortsighted," Dodd said.

Republican Senator John McCain said it was more important to rein in unnecessary spending at a time when the country is amassing a record $1.8 trillion budget deficit.

McCain, Obama's rival in the 2008 presidential contest, said the president deserved credit for "being very firm on this issue" and described the vote as a "big victory for the American taxpayer."

The overall defense authorization bill includes $550.4 billion for military operations and $130 billion for the wars in Afghanistan and Iraq for the fiscal year starting October 1.
The bill has become a vehicle for several provisions unrelated to military spending, such as the Iran amendment.

Last week, the Senate approved a measure that would expand hate-crime protection to gays and lesbians, and on Monday also extended that protection to military members.
On Wednesday, the Senate is scheduled to consider a provision that would make it easier for gun owners to carry concealed weapons across state lines.

The House version includes $369 million in advanced procurement funds as a down payment on 12 more F-22 jets in fiscal 2011.

A final vote on the Senate bill could come later this week, but the two chambers might not begin to hammer out their differences until September.

What Supersonic Looks Like

2009-07-01T18:28:00.001+08:00

A U.S. Air Force F-22 Raptor executes a supersonic flyby over the flight deck of the aircraft carrier USS John C. Stennis (CVN 74) in the Gulf of Alaska, in this handout photo taken on June 22, 2009. The John C. Stennis is participating in Northern Edge 2009, a joint exercise focusing on detecting and tracking units at sea, in the air and on land. Picture taken on June 22, 2009.

2009-06-29T19:07:00.002+08:00

HB-SIA solar-powered aircraft

2009-06-28T00:35:00.005+08:00

The HB-SIA solar-powered aircraft, the first prototype of the Solar Impulse project, is to be unveiled next week on June 26 at Dübendorf air base, near Zurich, Switzerland. Those who attend will discover some design changes since the last images were released, company CEO André Borschberg told AIN, adding that a first flight is planned for later this year.

In February, Solar Impulse engineers were elated when the main spar successfully completed load tests, which simulated situations such as a combination of turbulence and extreme piloting maneuvers. The trials involved flexion and torsion of the aircraft’s 200-foot-long spar. The spar was fixed at its center and lead weights were gradually added onto approximately 30 platforms suspended by cables or winches distributed along its span. They were loaded in four stages–25, 50, 75 and 100 percent–yielding a total load equivalent to 3.5gs. With the total load–comprising 5.5 metric tons of lead–the deflection measured at the wing tips was almost four feet.

Ten people worked eight months to manufacture the spar, which underwent 60 thermal treatments to meet resistance and weight goals.

Two months earlier, in December, the spar underwent vibration testing aimed at assessing the risk of resonance. The tests defined the aircraft’s natural frequencies and checked the correspondence between the model calculated by the engineers and its real technical characteristics.

Using electrodynamic devices fixed at different points on the airframe, German aerospace research agency (DLR) experts caused the aircraft to vibrate. They measured the repercussions with 71 sensors placed along the spar, the fuselage, the tailboom and the engine and battery supports. In all, they tested around 100 vibration modes at frequencies varying from 8 to 20 Hz.

The test results revealed a few minimal differences with the computer model that the engineers had developed. The elasticity modulus for the structure turned out to be slightly lower than planned, which was good news because the aircraft is more flexible than they anticipated.

The Solar Impulse defies normal aircraft conventions: “It is the size of an Airbus, has the weight of a car and runs on the power of a scooter,” Borschberg quipped.

The aircraft weighs just 3,300 pounds. Its batteries are charged by 2,150 sq ft of photovoltaic cells affixed to the wing. The photovoltaic cells–which are composed of single-crystal silicon with a 180-micron thickness–are at the forefront of solar technology. They are said to offer 22 percent efficiency.

The wing also carries four 10-hp electric motors, and over a 24-hour period, the Solar Impulse’s average speed is projected to be close to 38 knots.

Of course, building a solar aircraft makes sense only if it can also fly at night. Energy accumulated during the day will be stored in two ways. One way is electric, via the HB-SIA’s batteries which have an energetic density of 225 Wh per kilogram. The second way is potential energy: the pilot will have the aircraft climbing during daytime, and at night, this will allow the aircraft to lose altitude while keeping to the preset flight profile.

HB-SIA is the first of two aircraft planned to be built. It is scheduled to perform full 36-hour flight cycles, hopefully this year. However, as Borschberg’s team has set its sights on an around-the-world flight (including stopovers), it needs a bigger airplane, which it will build with lessons learned from the HB-SIA. Plans are for a flight across the Atlantic in 2011.

The Solar Impulse’s project initiator is Bertrand Piccard, who flew nonstop around the world in a balloon 10 years ago. Piccard and Borschberg are to be the HB-SIA’s pilots. Both already have performed long-duration simulated flights on the ground in the aircraft’s single-seat cockpit.

In the past, solar technology pioneers flew unmanned aircraft at night using the electricity produced onboard during the day; others flew several hundred miles in one day. None of them, however, combined manned flight with long duration.

Solar Impulse partners include, among others, aircraft manufacturer Dassault, the International Air Transport Association (IATA), engineer consultancy firm Altran, chemical and materials specialist Solvay, watchmaker Omega, the Ecole Polytechnique Fédérale de Lausanne (EPFL) and Deutsche Bank.

Paragliding

2009-05-14T00:18:00.006+08:00

Paragliding is a recreational and competitive flying sport. A paraglider is a free-flying, foot-launched aircraft. The pilot sits in a harness suspended below a fabric wing, whose shape is formed by its suspension lines and the pressure of air entering vents in the front of the wing.

History

In 1952 Domina Jalbert advance governable parachutes with multi-cells and controls for controlling lateral glide of the device.

In 1954, Walter Neumark predicted (in an article in Flight magazine) a time when a glider pilot would be “able to launch himself by running over the edge of a cliff or down a slope ... whether on a rock-climbing holiday in Skye or ski-ing in the Alps”.

In 1961, the French engineer Pierre Lemoigne produced improved parachute designs which led to the Para-Commander (‘PC’), which had cut-outs at the rear and sides that enabled it to be towed into the air and steered – leading to parasailing/parascending.

Sometimes credited with the greatest development in parachutes since Leonardo da Vinci, the American Domina Jalbert invented his filed-for January 10, 1963 US Patent 3131894 the Parafoil which had sectioned cells in an aerofoil shape; an open leading edge and a closed trailing edge, inflated by passage through the air – the ram-air design.

Meanwhile, David Barish was developing the Sail Wing for recovery of NASA space capsules – “slope soaring was a way of testing out ... the Sail Wing”.After tests on Hunter Mountain, New York in September 1965, he went on to promote ‘slope soaring’ as a summer activity for ski resorts (apparently without great success).NASA originated the term ‘paraglider’ in the early 1960s, and ‘paragliding’ was first used in the early 1970s to describe foot-launching of gliding parachutes.

Author Walter Neumark wrote Operating Procedures for Ascending Parachutes, and he and a group of enthusiasts with a passion for tow-launching ‘PCs’ and ram-air parachutes eventually broke away from the British Parachute Association to form the British Association of Parascending Clubs (BAPC) in 1973. Authors Patrick Gilligan (Canada) and Betrand Dubuis (Switzerland) wrote the first flight manual "The Paragliding Manual" in 1985, officially coining the word Paragliding.

These threads were pulled together in June 1978 by three friends Jean-Claude Bétemps, André Bohn and Gérard Bosson from Mieussy Haute-Savoie, France. After inspiration from an article on ‘slope soaring’ in the Parachute Manual magazine by parachutist & publisher Dan Poynter, they calculated that on a suitable slope, a ‘square’ ram-air parachute could be inflated by running down the slope; Bétemps launched from Pointe du Pertuiset, Mieussy, and flew 100 m. Bohn followed him and glided down to the football pitch in the valley 1000 metres below. ‘Parapente’ (pente being French for slope) was born.

From the 1980s equipment has continued to improve and the number of paragliding pilots has continued to increase. The first World Championship was held in Kössen, Austria in 1989.

Equipment

Wing

The paraglider wing or canopy is known in aeronautical engineering as a ram-air airfoil, or parafoil. Such wings comprise two layers of fabric which are connected to internal supporting material in such a way as to form a row of cells. By leaving most of the cells open only at the leading edge, incoming air (ram-air pressure) keeps the wing inflated, thus maintaining its shape. When inflated, the wing's cross-section has the typical teardrop aerofoil shape.

Note: In some modern paragliders (from the 90's onwards), especially higher performance wings, some of the cells of the leading edge are closed to form a cleaner aerodynamic airfoil. Like the wingtips, these cells are kept inflated by the internal pressure of the wing.The pilot is supported underneath the wing by a network of lines. The lines are gathered into two sets as left and right risers. The risers collect the lines in rows from front to back in either 3 or 4 rows, distributing load as in a whippletree. The risers are connected to the pilot's harness by two carabiners.

Paraglider wings typically have an area of 20-35 m2 with a span of 8–12 m, and weigh 3–7 kg. Combined weight of wing, harness, reserve, instruments, helmet, etc. is around 12–18 kg.

The glide ratio of paragliders ranges from 8:1 for recreational wings, to about 11:1 for modern competition models[citation needed]. For comparison, a typical skydiving parachute will achieve about 3:1 glide. A hang glider will achieve about 15:1 glide. An idling (gliding) Cessna 152 will achieve 9:1. Some sailplanes can achieve a glide ratio of up to 72:1.

The speed range of paragliders is typically 20–60 km/h (12-34 mph), from stall speed to maximum speed. Beginner wings will be in the lower part of this range, high-performance wings in the upper part of the range. The range for safe flying will be somewhat smaller.

Modern paraglider wings are made of high-performance non-porous fabrics such as Skytex (Porcher Sport) & Gelvenor, with Dyneema/Spectra or Kevlar/Aramid lines.

For storage and carrying, the wing is usually folded into a rucksack (bag), which can then be stowed in a large backpack along with the harness.

For pilots who may not want the added weight or fuss of a backpack, the harness itself can be used to carry the wing, though this is less comfortable, and thus less favorable for longer hikes. In this case the wing (within the rucksack) is buckled into the harness seat, which is then slung over the shoulders. Recent developments in light-weight harness design include the ability to turn the harness inside out such that it becomes the backpack, thus removing the need for a second storage system.

Tandem paragliders, designed to carry the pilot and one passenger, are larger but otherwise similar. They usually fly faster with higher trim speeds, are more resistant to collapse, and have a slightly higher sink rate compared to solo paragliders.

Since 2000 Juan Salvadori from Argentina has been exploring a variant wing termed Paramontante that involves some firm beams. In April 2009 Pere Casellas has joined in a collaboration with Juan Salvadori for polishing the paramontante. Laboratori d'envol Paramontante

Harness

The pilot is loosely and comfortably buckled into a harness which offers support in both the standing and sitting positions. Modern harnesses are designed to be as comfortable as a lounge chair in the sitting position. Many harnesses even have an adjustable 'lumbar support'.

A reserve parachute is also typically connected to a paragliding harness.

Parachutes, including skydiving canopies, primary design purpose is for descending, such as jumping out of an aircraft or for dropping cargo; while paragliders design purpose is for ascending.

Paragliders are categorized as "ascending parachutes" by canopy manufacturers worldwide, and are designed for "free flying" meaning flight without a tether (for tethered flight amusement, see parasailing).However, in areas without high launch points, paragliders may be towed aloft by a ground vehicle or a stationary winch, after which they are released, creating much the same effect as a mountain launch.

Such tethered launches can give a paraglider pilot a higher starting point than many mountains do, offering similar opportunity to catch thermals and to remain airborne by "thermaling" and other forms of lift.As free flight, paragliding requires the significant skill and training required for aircraft control, including aeronautical theory, meteorological knowledge and forecasting, personal/emotional safety considerations, adherence to applicable Federal Aviation Regulations (US), and knowledge of equipment care and maintenance.

Instruments

Most pilots use variometers, radios, and, increasingly, GPS units when flying.

Variometer

Birds are highly sensitive to atmospheric pressure, and can tell when they are in rising or sinking air. People can sense the acceleration when they first hit a thermal, but cannot detect the difference between constant rising air and constant sinking air, so turn to technology to help. Modern variometers are capable of detecting rates of climb or sink of 1 cm per second, such is the case of the Flymaster B1 which uses extremely low noise electronics and complex algorithms to detect such minute changes in air pressure.

A variometer indicates climb-rate (or sink-rate) with audio signals (beeps which increase in pitch and tempo as you accelerate upwards and a droning sound which gets deeper as your descent rate increases) and/or a visual display. It also shows altitude: either above takeoff, above sea level, or (at higher altitudes) "flight level".The main purpose of a variometer is in helping a pilot find and stay in the "core" of a thermal to maximise height gain, and conversely indicating when he or she is in sinking air, and needs to find rising air.

The more advanced variometers have an integrated GPS. This is not only more convenient, but also allows to record the flight in three dimensions. The track of the flight is digitally signed, stored and can be downloaded after the landing. Digitally signed tracks can be used as proof for record claims, replacing the 'old' method of photo documentation.

Radio

Pilots use radio for training purposes, for communicating with other pilots in the air, particularly when travelling together on cross-country flights, and for reporting the location of landing.

Radios used are PTT (push-to-talk) transceivers, normally operating in or around the FM VHF 2-metre band (144–148 MHz) , often without the correct licence, and causing interference problems with legitimate users for many miles around. Usually a microphone is incorporated in the helmet, and the PTT switch is either fixed to the outside of the helmet, or strapped to a finger.

GPS

GPS (global positioning system) is a necessary accessory when flying competitions, where it has to be demonstrated that way-points have been correctly passed.It can also be interesting to view a GPS track of a flight when back on the ground, to analyze flying technique. Computer software is available which allows various different analyses of GPS tracks.

Other uses include being able to determine drift due to the prevailing wind when flying at altitude, providing position information to allow restricted airspace to be avoided, and identifying one’s location for retrieval teams after landing-out in unfamiliar territory.

More recently, the use of GPS data, linked to a computer, has enabled pilots to share 3D tracks of their flights on Google Earth. This fascinating insight allows comparisons between competing pilots to be made in a detailed 'post-flight' analysis.

Control

Brakes: Controls held in each of the pilot’s hands connect to the trailing edge of the left and right sides of the wing. These controls are called 'brakes' and provide the primary and most general means of control in a paraglider. The brakes are used to adjust speed, to steer (in addition to weight-shift), and flare (during landing).

Weight Shift: In addition to manipulating the brakes, a paraglider pilot must also lean in order to steer properly. Such 'weight-shifting' can also be used for more limited steering when brake use is unavailable, such as when under 'big ears' (see below). More advanced control techniques may also involve weight-shifting.

Speed Bar: A kind of foot control called the 'speed bar' (also 'accelerator') attaches to the paragliding harness and connects to the leading edge of the paraglider wing, usually through a system of at least two pulleys (see animation in margin). This control is used to increase speed, and does so by decreasing the wing's angle of attack. This control is necessary because the brakes can only slow the wing from what is called 'trim speed' (no brakes applied). The accelerator is needed to go faster than this.

More advanced means of control can be obtained by manipulating the paraglider's risers or lines directly:

Most commonly, the lines connecting to the outermost points of the wing's leading edge can be used to induce the wingtips to fold under. The technique, known as 'big ears', is used to increase rate of descent (see picture).

The risers connecting to the rear of the wing can also be manipulated for steering if the brakes have been severed or are otherwise unavailable.

In a 'B-line stall', the second set of risers from the leading-edge/front is gently pulled down to put a crease across the lower surface of the wing (this will also distort the upper surface) acting as an 'air brake' significantly reducing airspeed. The combination of reduced forward airspeed and increased vertical airspeed destroys the laminar flow of air over the aerofoil, dramatically reducing the lift produced by the canopy, thus inducing a higher rate of descent.

Fast Descents

Problems with “getting down” can occur when the lift situation is very good or when the weather changes unexpectedly. There are three possibilities of rapidly reducing altitude in such situations.

Spiral Dive

The spiral dive is the most effective form of fast descent: With a little bit of practice you will achieve a sink rate of 15 m/s and more. It is absolutely necessary that you gradually approach these values the first few times! Constant pulling on one brake narrows the radius of the turn and forms a spiral rotation in which high sink rates can be reached. As soon as the glider is in a spiral dive (clear increase of sink rate and turn bank), the outside wing should always be stabilised with the outside brake and the desired sink rate should be controlled with great delicacy.

B-Line-Stall

Out of unaccelerated normal flight, it is best to grasp the B-lines on both sides above the line links and pull them down. There is no need to release the toggles while B-stalling. Then a full stall will occur, the canopy bunches up in the direction of the profile and by pulling down further you will achieve a high sink rate while keeping a completely stable “flight” position. Pulling the B-lines even further down will not enhance the sink rate but lead to a more unstable flight position and turning away of the canopy. By releasing the risers the canopy will accelerate immediately without strong oscillation effects. Should it not catch up right away, a simultaneous push on the A-risers will remedy this condition.

Big Ears

By pulling on the rear (outer) A-riser and holding down the outer A-lines the wing tips of the glider can be folded in. This method drastically deteriorates the glide angle without necessarily affecting forward speed. The effectiveness of this technique can be increased by using the speed system at the same time. To reinflate on a low performance glider (e.g. DHV1 rated) it is simply necessary to release the lines.On higher performance gliders (e.g. DHV1/2 and above) it may be necessary to help the reinflation with brief, deep pumps of the brakes. Whilst big ears are in use, the loading on the glider is increased and it is therefore more stable and less prone to collapse. However the stall speed is raised and so the pilot must be very cautious about applying brake (it is best not to).

Flying

Launching

As with all aircraft, launching and landing are done into wind (though in mountain flying, it is possible to launch in nil wind and glide out to the first thermal).

Forward launch

In low winds, the wing is inflated with a ‘forward launch’, where the pilot runs forward so that the air pressure generated by the forward movement inflates the wing.

Reverse launch

In higher winds, particularly ridge soaring, a ‘reverse launch’ is used, with the pilot facing the wing to bring it up into a flying position, then turning under the wing to complete the launch.Reverse launches have a number of advantages over a forward launch. It is more straight forward to inspect the wing and check the lines are free as it leaves the ground. In the presence of wind, the pilot can be tugged toward the wing and facing the wing makes it easier to resist this force, and safer in case the pilot slips (as opposed to being dragged backwards).

These launches are normally attempted with a reasonable wind speed making the ground speed required to pressurise the wing much lower - the pilot is initially launching while walking forwards as opposed to running backward.

Towed launch

In flatter countryside pilots can also be launched with a tow. Once at full height, the pilot pulls a release cord and the towline falls away. This requires separate training, as flying on a winch has quite different characteristics from free flying.There are two major ways to tow: Pay-in and pay-out towing. Pay-in towing involves a stationary winch that pays in the towline and thereby pulls the pilot in the air. The distance between winch and pilot at the start is around 500 meters or more. Pay-out towing involves a moving object, like a car or a boat, that pays out line slower than the speed of the object thereby pulling the pilot up in the air. In both cases it is very important to have a gauge indicating daN to avoid pulling the pilot out of the air.There is one other form of towing; ‘static’ towing. This involves a moving object, like a car or a boat, attached to a paraglider or hanglider with a fixed length line. This is very dangerous because now the forces on the line have to be controlled by the moving object itself, which is almost impossible to do. With static line towing a lockout is bound to happen sooner or later. Static line towing is forbidden in most countries and if not, should be avoided at all cost.

Landing

Landing involves lining up for an approach into wind, and just before touching down, ‘flaring’ the wing to minimise vertical speed.

In light winds, some minor running is common. In moderate to medium headwinds, the landings can be without forward speed.

Ridge soaring

In ridge soaring, pilots fly along the length of a ridge feature in the landscape, relying on the lift provided by the air which is forced up as it passes over the ridge.

Ridge soaring is highly dependent on a steady wind within a defined range (the suitable range depends on the performance of the wing and the skill of the pilot). Too little wind, and insufficient lift is available to stay airborne (pilots end up ‘scratching’ along the slope). With more wind, gliders can fly well above and forward of the ridge, but too much wind, and there is a risk of being ‘blown back’ over the ridge.

Thermal flying

When the sun warms the ground, it will warm some features more than others (such as rock-faces or large buildings), and these set off thermals which rise through the air. Sometimes these may be a simple rising column of air; more often, they are blown sideways in the wind, and will break off from the source, with a new thermal forming later.

Once a pilot finds a thermal, he or she begins to fly in a circle, trying to center the circle on the strongest part of the thermal (the "core"), where the air is rising the fastest. Most pilots use a ‘vario’ (vario-altimeter), which indicates climb rate with beeps and/or a visual display, to help ‘core-in’ on a thermal.

Coring: The technique to "core" a thermal is simple: turn tighter as lift decreases, and turn less as lift increases. This ensures you are always flying around the core.

Often there is strong sink surrounding thermals, and there is often also strong turbulence resulting in wing collapses as a pilot tries to enter a strong thermal. Once inside a thermal, shear forces reduce somewhat and the lift tends to become smoother.

Good thermal flying is a skill which takes time to learn, but a good pilot can often "core" a thermal all the way to cloud base.

Cross-country flying

Once the skills of using thermals to gain altitude have been mastered, pilots can glide from one thermal to the next to go ‘cross-country’ (‘XC’). Having gained altitude in a thermal, a pilot glides down to the next available thermal.Potential thermals can be identified by land features which typically generate thermals, or by cumulus clouds which mark the top of a rising column of warm, humid air as it reaches the dew point and condenses to form a cloud. In many flying areas, cross-country pilots also need an intimate familiarity with air law, flying regulations, aviation maps indicating restricted airspace, etc.

In-flight Wing Deflation (Collapse)

Since the shape of the wing (airfoil) is formed by the moving air entering and inflating the wing, in turbulent air part or all of the wing (airfoil) can deflate (collapse). Piloting techniques referred to as "active flying" will greatly reduce the frequency and severity of deflations or collapses. On modern recreational wings, such deflations will normally recover themselves without pilot intervention.In the event of a severe deflation, correct pilot input will speed recovery from a deflation, but incorrect pilot input may slow the return of the glider to normal flight, so pilot training and practice in correct response to deflations is necessary.

For the rare case where it is not possible to recover from a deflation (or from other threatening situations such as a spin), most pilots carry a reserve (rescue, emergency) parachute.Most pilots never have cause to ‘throw’ their reserve. In case the wing deflation happens near ground, i.e. shortly after takeoff or just before landing, the wing (paraglider) may not recover (airfoil shape) even with pilot intervention and there may not be enough time for successful rescue parachute deployment.

Those cases can result in serious bodily injury or death. In-flight wing deflation and other hazards are minimized by flying a suitable glider, and choosing appropriate weather conditions and locations, for the pilot's skill and experience level.

Safety

Paragliding is perhaps often viewed as a higher-risk sport than it actually is. Nonetheless, there is great potential for injury for the reckless or ill-prepared.

The safety of the sport is directly proportional to the skill and sense of the pilot. It's important to note that almost all paragliding accidents are the result of pilot error. Paragliding equipment is very well built and, if properly cared for, will never fail.As an example, the average paraglider has around 30 lines connected to the risers, yet each one is strong enough to support the full weight of a pilot individually. Aerodynamically, newer paragliders that are not within advanced or competition categories are rated for safety and will tend to recover from most incidents on their own (without pilot intervention).

Given that equipment failure of properly certified paragliding equipment can be considered a non-issue, it is accurate to say that paragliding can be a very safe sport. The individual pilot is the ultimate indicator of his or her personal safety level.

In general:

The safe pilot will not fly at sites that pose an unreasonable challenge to his/her flying skills.

The safe pilot will not be influenced by the possibly negative examples set by others.

The safe pilot will only fly on days in which the weather is conducive to safe flight. Turbulence in all its forms is enemy #1 for a flying paraglider wing. Because paragliders have no solid support, their shape (and ability to fly) can be ruined by an errant down draft or the like. Therefore, turbulence or conditions conducive to turbulence generation is a primary factor in determining whether the weather is safe.

The following weather is to be avoided:

Excessive wind speed or gustiness. 15mph wind is fairly windy for a paraglider, and most pilots won't take off in much more wind than that. High winds will also increase the effect of mechanical turbulence. Gusty conditions will make take-offs and landings more dangerous and will make collapses more likely while in flight.

A wind direction that will not allow a take-off (or landing) into the wind, or at least generally so. Tail-wind take-offs are to be avoided at all cost. Assurance that an [apparent] headwind is not actually a 'rotor' is also critical (rotors comprise a form of mechanical turbulence).

Excessively high atmospheric instability, indicated in part by overdeveloped cumulus clouds, or in worse situations by cumulo-nimbus cloud formation. Such conditions will contribute to turbulence. If cumulo-nimbus (thunderstorm) clouds are anywhere in sight, the effect of severe atmospheric instability may exist where you are.

Rain or snow. Because a paraglider wing is made from fabric, it has the ability to absorb moisture. Moreover, the weight (or lack thereof) of a paraglider wing is critical to its performance. Flying into heavy rain or snow will weigh the wing down and may terminate a flight quickly. A wet wing is also less controllable, less stable (more prone to collapse) and will exhibit less tendency to recover into normal flight.

General safety precautions include pre-flight checks, helmets, harnesses with back protection (foam or air-bag), reserve parachutes, and careful pre-launch observation of other pilots in the air to evaluate conditions.

For pilots who want to stretch themselves into more challenging conditions, advanced ‘SIV’ (simulation d’incidents en vol, or simulation of flying incidents) courses are available to teach pilots how to cope with hazardous situations which can arise in flight.Through instruction over radio (above a lake), pilots deliberately induce major collapses, stalls, spins, etc, in order to learn procedures for recovering from them. (As mentioned above, modern recreational wings will recover from minor collapses without intervention).

As always, fatalities and freak accidents can occur, but most properly-trained, responsible pilots risk only minor injuries, such as twisted ankles.

Learning to fly

Most popular paragliding regions have a number of schools, generally registered with and/or organized by national associations. Certification systems vary widely between countries, though around 10 days instruction to basic certification is standard.

There are several key components to a paragliding pilot certification instruction program. Initial training for beginning pilots usually begins with some amount of ground school to discuss the basics, including elementary theories of flight as well as basic structure and operation of the paraglider.

Students then learn how to control the glider on the ground, practicing take-offs and controlling the wing 'overhead'. Low, gentle hills are next where students get their first short flights, flying at very low altitudes, to get used to the handling of the wing over varied terrain. Special winches can be used to tow the glider to low altitude in areas that have no hills readily available.

As their skills progress, students move on to steeper/higher hills (or higher winch tows), making longer flights, and learning to turn the glider, control the glider's speed, then moving on to 360° turns, spot landings, ‘big ears’ (used to increase the rate of descent for the paraglider), and other more advanced techniques. Training instructions are often provided to the student via radio, particularly during the first flights.

A third key component to a complete paragliding instructional program provides substantial background in the key areas of meteorology, aviation law, and general flight area etiquette.

To give prospective pilots a chance to determine if they would like to proceed with a full pilot training program, most schools offer tandem flights, in which an experienced instructor pilots the paraglider with the prospective pilot as a passenger. Schools often offer pilot's families and friends the opportunity to fly tandem, and sometimes sell tandem pleasure flights at holiday resorts.

Most recognised courses lead to a national licence and an internationally recognised International Pilot Proficiency Information/Identification card. The IPPI specifies five stages of paragliding proficiency, from the entry level ParaPro 1 to the most advance stage 5.

World records

FAI (Fédération Aéronautique Internationale) world records:

Straight distance – 461.6 km: Frank Brown, Marcelo Prieto, Rafael Monteiro Saladini (Brazil); Quixada – Duque, Brazil; 14 November 2007.

Straight distance to declared goal – 368.9 km: Aljaž Valič, Urban Valič (Slovenia); Vosburg – Jamestown (South Africa); 7 December 2006

Gain of height – 4526 m: Robbie Whittall (UK); Brandvlei (South Africa); 6 January 1993

Other records (distance/speed for out-and-return and triangular course) can be seen on the FAI site

Recently a flight of over 500 km was made in excellent conditions in South Africa; however this is awaiting full ratification.

Pilot numbers

Numbers of actively flying pilots can only be a rough estimate, but France is believed to have the largest number, at around 25,000. Next most active flying countries are Germany, Austria, Switzerland, Japan, and Korea, at around 10,000 – 20,000, followed by Italy, the UK, and Spain with around 5,000 – 10,000. The USA has around 4,500. (All as of 2004).

什么是飞行伞？

2009-05-02T01:10:00.002+08:00

什么是飞行伞？　　
飞行伞是一种双足起降、以充气软翼为主体的飞行器。其飞行动力是风力、重力和飞行员的操纵力。　　

飞行伞的组成部分？　　
飞行伞由伞体、伞绳、操纵带和鞍具组成。另外，还有刹车绳，用来控制飞行的速度和方向，挂钩，用来连接伞绳和鞍具。分述如次：　　

(1) 伞体：是由上层、下层、和隔间（气室）组成的。材质为30丹尼的强力尼龙布。　　
(2) 伞绳：可分为ABCDE共五组。材质为防弹纤维内芯，外敷尼龙。　　
(3) 操纵带：是将各组的伞绳相连接的组合带，依设计性能而有所不同。一般有ABCD四组。　　(4) 鞍具：即套带。分为肩带、胸带与腿带。胸带有H型及交叉型。为了保护飞行者的脊髓，通常类套带的下方与背部装有海绵或防弹纤维板、玻璃纤维板、气囊等保护装置。另外，在肩带前方各有一个挂钩，用来连接伞体与飞行员。　　

飞行伞和降落伞是一回事儿吗？　　
不是一回事儿。飞行伞有点象一个现代化的、可以操纵的空中滑行降落伞，但它与降落伞有几点重要的不同之处：　　
(1) 结构：飞行伞是一种起降设备，因此没有DROUGE伞或滑件，其构造也更为轻盈（因为它不需要承担高速降落中猛然打开时的冲力）。飞行伞的伞衣气室较多，伞绳也较细。　　
(2) 起飞方式：飞行伞一定要由一个有落差的山坡上逆风起飞，借着向前跑的速度及风吹的速度，产生將伞翼往上提的『升力』后，便会将人帶离地面。而高空跳伞必須要有航空载具，如：飞机、热气球等。　　
(3) 开伞程序：飞行伞在起飞前，已將伞衣打开铺在地面。高空跳伞是跳离载具后，经过一段自由落体（或立刻）将伞衣由伞包中拉出。　　
(4) 飞行性能：飞行伞可盘旋、滑翔、爬升、越野、滞空。高空伞仅能下降。
(5)外观：飞行伞的翼展较长，形狀接近梭形。高空伞为长方形，且上方多一个小小的引导伞，在跳伞员的头顶上有一块方形的減震布，用來減轻伞翼张开时的震动。　　

飞行伞与滑翔翼有什么区别？　　
(1) 滑翔翼有一个刚性框架，能保持翼体的三角形的形状。飞行伞的伞衣则靠空气压力维持其梭形、橢圓形、橄欖形的形状。　　
(2) 滑翔翼的的空气动力学结构较为明朗，其飞行速度比飞行伞要快得多。　　
(3) 滑翔翼的飞行员一般悬挂在翼体下方俯式飞行，其身体外包着一个象虫蛹似的吊袋。飞行伞的飞行员一般是坐在一个椅子式的鞍具上(有时为仰式)，胸前有两根吊袋与伞衣连接。　　
(4) 操纵方式：滑翔翼是利用身体的重心移动来操纵：前推-加速；后拉-减速；左移 -左转；右移-右转。飞行伞则是利用两条操纵绳，拉左手-左转；拉右手-右转；拉双手-减速。　　

一具伞能用多久？　　
在使用中，飞行伞会因为磨损、拉扯（这是主要因素）和风吹日晒等多种因素而老化。其使用寿命一般在4年左右，当然这同使用条件和使用频度有着相当密切的关系。　　

在空中飞行时应遵守什么交通规则？　　
空中飞行并不象很多人认为的那样是无拘无束，“天高任我飞”。由于在同一空域往往有多架飞行器同时飞行，所以我们也必须象在地面开车时一样，遵守特定的交通规划，以避免意外发生。一般规则如下：　　
(1) 速度快的要让速度慢的。　　
(2) 有动力的要让无动力的。　　
(3) 同向時，高度高的要让高度低的。　　
(4) 同向又同高度時，右边的先行。　　
(5) 两方相遇时各向右转。　　
(6) 超越時应由右方超越。　　
(7) 进入热气流盘旋时，以先进入气流者的方向为方向。　　
(8) 右侧靠山壁者可直行。　　
(9) 不要到当地航空管制部门指定的空域范围之外飞行，以免误闯军事敏感区、国家安全敏感区、边境管理区等。

Reaching for a Record

2009-05-01T06:56:00.004+08:00

Reaching for a RecordThe Waverider, a.k.a. the X-5, is illustrated here in flight. The experimental aircraft is designed to fly more than six times faster than the speed of sound on ordinary jet fuel

April 29, 2009 -- Hoping to bridge the gap between airplanes and rocketships, the U.S. military is preparing to test an experimental aircraft that can fly more than six times faster than the speed of sound on ordinary jet fuel.

Officially, it's known as the X-51, but folks like to call it the WaveRider because it stays airborne, in part, with lift generated by the shock waves of its own flight. The design stems from the goal of the program -- to demonstrate an air-breathing, hypersonic, combustion ramjet engine, known as a scramjet.

"We built a vehicle around an engine," said Joseph Vogel, the X-51 project manager with Boeing, which is building a series of four test planes under a $246.5-million program managed by the Air Force Research Laboratory in Dayton, Ohio.

Cockpit Voice Recorders

2009-04-20T09:03:00.001+08:00

Cockpit Voice Recorders

In almost every commercial aircraft, there are several microphones built into the cockpit to track the conversations of the flight crew. These microphones are also designed to track any ambient noise in the cockpit, such as switches being thrown or any knocks or thuds. There may be up to four microphones in the plane's cockpit, each connected to the cockpit voice recorder (CVR).

Any sounds in the cockpit are picked up by these microphones and sent to the CVR, where the recordings are digitized and stored. There is also another device in the cockpit, called the associated control unit, that provides pre-amplification for audio going to the CVR. Here are the positions of the four microphones:

Pilot's headset
Co-pilot's headset
Headset of a third crew member (if there is a third crew member)
Near the center of the cockpit, where it can pick up audio alerts and other sounds

Most magnetic-tape CVRs store the last 30 minutes of sound. They use a continuous loop of tape that completes a cycle every 30 minutes. As new material is recorded, the oldest material is replaced. CVRs that used solid-state storage can record two hours of audio. Similar to the magnetic-tape recorders, solid-state recorders also record over old material.

How Black Boxes Work

2009-04-20T08:43:00.007+08:00

Flight Data Recorders

The flight data recorder (FDR) is designed to record the operating data from the plane's systems. There are sensors that are wired from various areas on the plane to the flight-data acquisition unit, which is wired to the FDR. When a switch is turned on or off, that operation is recorded by the FDR.

In the United States, the Federal Aviation Administration (FAA) requires that commercial airlines record a minimum of 11 to 29 parameters, depending on the size of the aircraft. Magnetic-tape recorders have the potential to record up to 100 parameters. Solid-state FDRs can record more than 700 parameters. On July 17, 1997, the FAA issued a Code of Federal Regulations that requires the recording of at least 88 parameters on aircraft manufactured after August 19, 2002.

Here are a few of the parameters recorded by most FDRs:

Time
Pressure altitude
Airspeed
Vertical acceleration
Magnetic heading
Control-column position
Rudder-pedal position
Control-wheel position
Horizontal stabilizer
Fuel flow

Solid-state recorders can track more parameters than magnetic tape because they allow for a faster data flow. Solid-state FDRs can store up to 25 hours of flight data. Each additional parameter that is recorded by the FDR gives investigators one more clue about the cause of an accident.

Built to Survive
In many airline accidents, the only devices that survive are the crash-survivable memory units (CSMUs) of the flight data recorders and cockpit voice recorders. Typically, the rest of the recorders' chassis and inner components are mangled. The CSMU is a large cylinder that bolts onto the flat portion of the recorder. This device is engineered to withstand extreme heat, violent crashes and tons of pressure. In older magnetic-tape recorders, the CSMU is inside a rectangular box.

Using three layers of materials, the CSMU in a solid-state black box insulates and protects the stack of memory boards that store the digitized information. We will talk more about the memory and electronics in the next section. Here's a closer look at the materials that provide a barrier for the memory boards, starting at the innermost barrier and working our way outward:

Aluminum housing - There is a thin layer of aluminum around the stack of memory cards.

High-temperature insulation - This dry-silica material is 1 inch (2.54 cm) thick and provides high-temperature thermal protection. This is what keeps the memory boards safe during post-accident fires.

Stainless-steel shell- The high-temperature insulation material is contained within a stainless-steel cast shell that is about 0.25 inches (0.64 cm) thick. Titanium can be used to create this outer armor as well.

Testing a CSMU

To ensure the quality and survivability of black boxes, manufacturers thoroughly test the CSMUs. Remember, only the CSMU has to survive a crash -- if accident investigators have that, they can retrieve the information they need. In order to test the unit, engineers load data onto the memory boards inside the CSMU. L-3 Communications uses a random pattern to put data onto every memory board. This pattern is reviewed on readout to determine if any of the data has been damaged by crash impact, fires or pressure.

There are several tests that make up the crash-survival sequence:

Crash impact - Researchers shoot the CSMU down an air cannon to create an impact of 3,400 Gs (1 G is the force of Earth's gravity, which determines how much something weighs). At 3,400 Gs, the CSMU hits an aluminum, honeycomb target at a force equal to 3,400 times its weight. This impact force is equal to or in excess of what a recorder might experience in an actual crash.

Pin drop - To test the unit's penetration resistance, researchers drop a 500-pound (227-kg) weight with a 0.25-inch steel pin protruding from the bottom onto the CSMU from a height of 10 feet (3 m). This pin, with 500-pounds behind it, impacts the CSMU cylinder's most vulnerable axis.

Static crush - For five minutes, researchers apply 5,000 pounds per square-inch (psi) of crush force to each of the unit's six major axis points.

Fire test - Researchers place the unit into a propane-source fireball, cooking it using three burners. The unit sits inside the fire at 2,000 degrees Fahrenheit (1,100 C) for one hour. The FAA requires that all solid-state recorders be able to survive at least one hour at this temperature.

Deep-sea submersion - The CSMU is placed into a pressurized tank of salt water for 24 hours.

Salt-water submersion - The CSMU must survive in a salt water tank for 30 days.

Fluid immersion - Various CSMU components are placed into a variety of aviation fluids, including jet fuel, lubricants and fire-extinguisher chemicals.
During the fire test, the memory interface cable that attaches the memory boards to the circuit board is burned away. After the unit cools down, researchers take it apart and pull the memory module out. They restack the memory boards, install a new memory interface cable and attach the unit to a readout system to verify that all of the preloaded data is accounted for.

Black boxes are usually sold directly to and installed by the airplane manufacturers. Both black boxes are installed in the tail of the plane -- putting them in the back of the aircraft increases their chances of survival. The precise location of the recorders depends on the individual plane. Sometimes they are located in the ceiling of the galley, in the aft cargo hold or in the tail cone that covers the rear of the aircraft.

"Typically, the tail of the aircraft is the last portion of the aircraft to impact," Doran said. "The whole front portion of the airplane provides a crush zone, which assists in the deceleration of tail components, including the recorders, and enhances the likelihood that the crash-protected memory of the recorder will survive."

Solid-state Technology

Solid-state recorders are considered much more reliable than their magnetic-tape counterparts, according to Ron Crotty, a spokesperson for Honeywell, a black-box manufacturer. Solid state uses stacked arrays of memory chips, so they don't have moving parts. With no moving parts, there are fewer maintenance issues and a decreased chance of something breaking during a crash.

Data from both the CVR and FDR is stored on stacked memory boards inside the crash-survivable memory unit (CSMU). In recorders made by L-3 Communications, the CSMU is a cylindrical compartment on the recorder. The stacked memory boards are about 1.75 inches (4.45 cm) in diameter and 1 inch (2.54 cm) tall.

The memory boards have enough digital storage space to accommodate two hours of audio data for CVRs and 25 hours of flight data for FDRs.

Airplanes are equipped with sensors that gather data. There are sensors that detect acceleration, airspeed, altitude, flap settings, outside temperature, cabin temperature and pressure, engine performance and more. Magnetic-tape recorders can track about 100 parameters, while solid-state recorders can track more than 700 in larger aircraft.

All of the data collected by the airplane's sensors is sent to the flight-data acquisition unit (FDAU) at the front of the aircraft. This device often is found in the electronic equipment bay under the cockpit. The flight-data acquisition unit is the middle manager of the entire data-recording process. It takes the information from the sensors and sends it on to the black boxes.

Both black boxes are powered by one of two power generators that draw their power from the plane's engines. One generator is a 28-volt DC power source, and the other is a 115-volt, 400-hertz (Hz) AC power source. These are standard aircraft power supplies, according to Frank Doran, director of engineering for L-3 Communications Aviation Recorders.

飞行的原理

2009-04-20T08:29:00.005+08:00

飛機能飛上天空，主要是透過四種力量交互作用所產生的結果。這四種力量分別是引擎的推力、空氣的阻力、飛機自身的重力和空氣的升力。飛機以引擎的速度產生推力，並且以升力克服重力，使機身飛行空中; 當空氣流經機翼時，飛機的機翼截面形成拱形，上方的空氣分子因在同一時間內走較長的距離，相反地，下方的空氣分子跑得較快，造成在機翼上方的氣壓會較下方低，這樣，下方較高的氣壓就將飛機支撐著，並浮在空氣中，這就是物理學的伯努利原理 (伯努利: 十八世紀荷蘭出生的數學家與科學家)。當推力大於阻力、升力大於重力時，飛機就能起飛爬升，待飛機爬升到巡航高度時就收小油門，稱為平飛，這時候推力等於阻力、重力等於升力，也就是所謂的定速飛行。

推力為了使飛機前進，由引擎所產生的力。

阻力飛機前進時，空氣與之相反的力。

升力由於前進，在主翼上產生向上的力。

重力飛機的全體之重力。

1. 推力的來源（牛頓定律：作用力＝反作用力）:飛行的推力(或動力)是靠飛機利用螺旋槳所產生的，而噴射飛機則利用噴射引擎來產生推力; 紙飛機與滑翔機則以地球的重力(地心引力)而產生其前進速度。

2. 阻力的來源: 空氣對機身的阻力和摩擦力，所以，為提高飛行效率，在飛機設計上更接近流線型以減少不必要的阻力。但阻力是必須的，如用於飛機減速(機翼上擾流板升起)和穩定機身等用途。

3. 升力的來源: 板狀的物件遇到強風就會產生升力，如風箏便是一個好例子。當風箏的軌與風成一適當的角度時，便會不斷地往上升。故飛機的機翼與氣流保持某一傾斜角度時，會產生更大的升力。

4. 重力的來源：是飛機本身的全體重量，重力對飛行有負面影響，故飛機機身的設計都是採用較輕的材料。

主翼
是產生升力的最主要結構，沒有它，滑翔機就只能待在地面上了。滑翔機飛行時，受到氣流的影響，會傾向左右兩邊搖擺，所以兩翼要造成微微向上傾，形成上反角，亦即從機身前、後看，兩翼略成V字形，以減輕左右搖晃的傾向。滑翔機的機翼要有足夠的撓性，飛行中遇上紊流，可以稍微上下撲動，避免因變形而折斷。

副翼
副翼是連動的，也就是當駕駛桿扳向右，右副翼向上擺時，左副翼同時向下擺，如此滑翔機會往飛行員右下的方向翻滾。

擾流板
車子在路上跑時，如果想慢下來，踩煞車就可以了，但是滑翔機如何煞機呢？擾流板向上打開時，會將機翼上的氣流擾亂，而使滑翔機減慢速度並下降。這個功能在降落時也是很有用的。

水平尾翼
主翼除了提供升力之外，亦產生一個會造成滑翔機沿著主翼翼展方向的軸向下翻轉的力矩。這是造成許多飛行先驅喪生的原因之一。水平尾翼的功能就是提供一個矯正滑翔機俯仰或上下搖動的力矩，以確保飛行中的穩定性。

垂直尾翼
垂直尾翼能校正飛行中的偏行或左右迴轉，保持方向的穩定。

升降舵
升降舵也是用駕駛桿操控的。當駕駛桿向後扳，升降舵上擺，機頭朝上；駕駛桿向前推時，升降舵下擺，機頭朝下。

方向舵
方向舵是利用腳踏板來控制的。飛行員踩下左腳踏板時，方向舵向左擺，機頭左轉；踩下右腳踏板，方向舵向右擺，機頭就右轉。僅僅操縱方向舵只能改變滑翔機的位置，不能使滑翔機轉彎。滑翔機有很強的直線飛行慣性(牛頓第一定律)，轉動方向舵會引起側向滑行，就像開快車急彎時的感覺一樣，急彎路面通常會傾斜以防止車子打滑側行，但是滑翔機在空中是自由的，要使滑翔機轉彎而不側滑，必須同時操縱副翼與方向舵。英文叫做bank，傾斜轉彎

轻松一下

2009-04-09T03:03:00.002+08:00

飞机上的笑话！

有一位朋友要请关帝的神像回家，如果放在行李架上，怕对关帝不敬，于是那朋友就帮神像买了个位子，把神像放在位置上，绑上安全带，一切准备就绪，就等着飞机起飞了。可是呢……飞机却迟迟没有起飞。当那朋友不耐烦时，听到了空中小姐的广播“关云长先生，关云长先生听到广播请快点登机。“

由于是第一次坐飞机，陈太太的两个孩子，兴奋的坐立不安，
在走道上跑来跑去，还差点撞到空姐手上的饮料，
陈太太就责备她那两个孩子说:「要玩就出去玩。」

飞机快起飞时，空中小姐通知乘客：「女士、先生们，请扣紧您的安全带，
飞机快起飞了。」
飞了将近半小时，扩音机再度传来空中小姐的声音：「女士、先生们，
请将安全带再扣紧一些，很抱歉，我们忘了把今天的早餐运上飞机了！」

某日，一位小女孩搭某班飞机从台北飞高雄，这班飞机是她姐姐在服务的航空公司，而她姐姐也正好在这班飞机上做空姐服务员。
姐姐在家里向小妹交代：「上飞机不要吵别人，不要乱要东西给别人增加麻烦。」
小妹在座位上安份守己乖乖的坐着，但姐姐的同事却认出了小妹妹，
特别拿了罐可乐给小妹妹喝，姐姐在不久后过来巡查时看到了，
顺手就拿起手上的报纸卷起来，
从妹妹头上就是一棒，说道：「就叫?不要麻烦别人了，还讲不听!!!」
后来这班飞机的后舱在整个旅程都安安静静，没人跟空姐点饮料或是要报纸.....。

在高空30，000英?的班机中，空中小姐问牧师要不要喝点酒，
牧师说：『现在的高度如何呢？阿门。』
空中小姐：『30，000英?的高空』
牧师说：『啊！那还是不要吧！距总部太近了。』

有一架飞机，上面的乘客除了一个小学生之外，其余的都是一些重要的政府官员...
在飞机起飞不久后飞机就出事了，再过不久可能会坠机，
飞机上的人必须要用降落伞逃生，
可是发现飞机上的降落伞刚好不够一个，
于是那些大官们不管三七二十一就抢着降落伞纷纷逃生，
最后飞机上只剩下驾驶员和那个小学生，
于是驾驶员就对小学生说：『剩下一个降落伞就给你用好了，我与飞机共存亡....』
小学生说：『不用啊，降落伞还有两个，刚刚有一个伯伯背着我的书包跳下去了

一架飞机正准备进入跑道时突然又折回停机坪。
过了30分钟飞机又退出停机坪并顺利的起飞。
当飞机起飞后，一位乘客忍不住好奇的问空服员，为什麽飞机第一次起飞前到折回机场，而且也没有人跟乘客报告发生了什麽事？
空服员就对他说，因为第一次要起飞前机长听到引擎有怪声音，所以他就回去换了一位敢开的机长上来。

一位放假中的空服员搭乘波音的飞机，准备到欧洲去渡假。
飞机当时经过暴风雨地带，摇晃的非常厉害。
她的旁边做了一位男士紧张的抓着前面的椅背，脸色苍白又不断的冒冷汗，眼睛紧盯着窗外大力摇摆的机翼。这位空服员就试着告诉这位男士，她有很多年的飞行经验，经历过很多不寻常的航程，同时她也告诉他，一切都在机长的掌控下，没什麽好担心的。
「小姐」他回答，「我是波音的工程师，当初在设计时，这架飞机的机翼是不能承受这种幅度的摇摆的。

某繁忙的机场，有一次在尖峰时间，一次架A320的班机因为零件维修的原因必须延迟起飞的时间，於是全机的人都下了飞机。
由於下一班飞机必须使用这个登机口，地勤人员通知大家到机场东边的15号登机口等候。
当全部的人都到了15号登机口时，却发现登机门又改到南边的8号登机口，一行人於是又带了所有的手提行李来到8号登机口。
当所有的人都终於上了飞机，空服员做了下面的广播：「各位先生、各位女士，很抱歉-耽误了大家的时间，也让大家跑了不少地方。」
本班机是飞往华盛顿的，如果您上错飞机，请您现在离开。
广播完之後，机长满脸通红的从驾驶舱中跑出来，说：「不好意思，我上错飞机了．」

2009-04-09T03:03:00.001+08:00

History of Aircraft Engines

2009-04-09T02:30:00.003+08:00

History of aircraft engines，This list is incomplete

1633: Lagari Hasan Çelebi took off with what was described to be a cone shaped rocket and then glided with wings into a successful landing

1848: John Stringfellow made a steam engine capable of powering a model, albeit with negligible payload

1903: The Wright brothers commissioned Charlie Taylor to build an inline aeroengine (12 horsepower) for the Wright Flyer

1906:Traian Vuia flew his first airplane "Vuia I" at Montesson on 18th of March, achieving the first ever "only by on-board means" flight, without any "outside assistance", be it an incline, rails, a catapult, etc.

1908: René Lorin patents a design for the ramjet engine

1909: Roger Ravaud' Gnôme rotary engine in Henry Farman's aircraft won the Grand Prix for the greatest non-stop distance flown - 180 kilometres (110 mi) - and created a world record for endurance flight

1910: Henri Coanda displays the first jet powered aircraft at the second International Aeronautic Salon in Paris; he also tries to pilot the jet aircraft however he crashlands.

1911: Adams-Farwell's rotary engines powered fixed-wing aircraft in the US

1916: Auguste Rateau suggests using exhaust-powered compressors to improve high-altitude performance, the first example of the turbocharger.

1930: in Frank Whittle submitted his first patent

1938: The German Heinkel HeS 3 turbojet propels the Heinkel He 118 into the air

1939-1942: The world's first turboprop-the Jendrassik Cs-1 is designed by the Hungarian mechanical engineer György Jendrassik

1944: Messerschmitt Me 163 Komet, the worlds first rocket propelled aircraft deployed

1947: Bell X-1 rocket propelled aircraft exceeds the sound barrier

1948: the first turboshaft engine, the 100 shp 782. In 1950 this work was used to develop the larger 280 shp (210 kW) Artouste

1949: The Leduc 010 the world's first ramjet powered aircraft flies

1950(late): Rolls-Royce Conway the worlds first production turbofan enters service

1960s: TF39 high bypass turbofan enters service delivering greater thrust and much better efficiency

1960s: X-15 rocket plane flys at more than 50 miles (80 km) altitude at more than 3,000 mph (4,800 km/h).

2002: HyShot scramjet flew in dive

2004: Hyper-X first scramjet to maintain altitude

Piston Engine Development

2009-04-09T02:18:00.014+08:00

Picture a tube or cylinder that holds a snugly fitting plug. The plug is free to move back and forth within this tube, pushed by pressure from hot gases. A rod is mounted to the moving plug; it connects to a crankshaft, causing this shaft to rotate rapidly. A propeller sits at the end of this shaft, spinning within the air. Here, in outline, is the piston engine, which powered all airplanes until the advent of jet engines.

Pistons in cylinders first saw use in steam engines. Scotland's James Watt crafted the first good ones during the 1770s. A century later, the German inventors Nicolaus Otto and Gottlieb Daimler introduced gasoline as the fuel, burned directly within the cylinders. Such motors powered the earliest automobiles. They were lighter and more mobile than steam engines, more reliable, and easier to start.

Some single-piston gasoline engines entered service, but for use with airplanes, most such engines had a number of pistons, each shuttling back and forth within its own cylinder. Each piston also had a connecting rod, which pushed on a crank that was part of a crankshaft. This crankshaft drove the propeller.

Cutaway view of a piston engine built by Germany's Gottlieb Daimler. Though dating to the 19th century, the main features of this motor appear in modern engines.

Engines built for airplanes had to produce plenty of power while remaining light in weight. The first American planebuilders—Wilbur and Orville Wright, Glenn Curtiss—used motors that resembled those of automobiles. They were heavy and complex because they used water-filled plumbing to stay cool.

A French engine of 1908, the "Gnome," introduced air cooling as a way to eliminate the plumbing and lighten the weight. It was known as a rotary engine. The Wright and Curtiss motors had been mounted firmly in supports, with the shaft and propeller spinning. Rotary engines reversed that, with the shaft being held tightly—and the engine spinning! The propeller was mounted to the rotating engine, which stayed cool by having its cylinders whirl within the open air.

Numerous types of Gnome engines were designed and built, one of the most famous being the 165-hp 9-N "Monosoupape" (one valve). It was used during WWI primarily in the Nieuport 28. The engine had one valve per cylinder. Having no intake valves, its fuel mixture entered the cylinders through circular holes or "ports" cut in the cylinder walls. The propeller was bolted firmly to the engine and it, along with the cylinders, turned as a single unit around a stationary crankshaft rigidly mounted to the fuselage of the airplane. The rotary engine used castor oil for lubrication.

During World War I, rotaries attained tremendous popularity. They were less complex and easier to make than the water-cooled type. They powered such outstanding fighter planes as German's Fokker DR-1 and Britain's Sopwith Camel. They used castor oil for lubrication because it did not dissolve in gasoline. However, they tended to spray this oil all over, making a smelly mess. Worse, they were limited in power. The best of them reached 260 to 280 horsepower (190 to 210 kilowatts).

America's greatest technological contribution during WWI was the Liberty 12-cylinder water-cooled engine. Rated at 410 hp. , it weighed only two pounds per horsepower, far surpassing similar types of engines mass-produced by England, France, Italy, and Germany at that time.

Thus, in 1917 a group of American engine builders returned to water cooling as they sought a 400-horsepower (300-kilowatt) engine. The engine that resulted, the Liberty, was the most powerful aircraft engine of its day, with the U.S. auto industry building more than 20,000 of them. Water-cooled engines built in Europe also outperformed the air-cooled rotaries, and lasted longer. With the war continuing until late in 1918, the rotaries lost favor.

In this fashion, designers returned to water-cooled motors that again were fixed in position. They stayed cool by having water or antifreeze flow in channels through the engine to carry away the heat. A radiator cooled the heated water. In addition to offering plenty of power, such motors could be completely enclosed within a streamlined housing, to reduce drag and thus produce higher speeds in flight. Rolls Royce, Great Britain's leading engine-builder, built only water-cooled motors.

Air-cooled rotaries were largely out of the picture after 1920. Even so, air-cooled engines offered tempting advantages. They dispensed with radiators that leaked, hoses that burst, cooling jackets that corroded, and water pumps that failed.

Thus, the air-cooled "radial engine" emerged. This type of air-cooled engine arranged its cylinders to extend radially outward from its hub, like spokes of a wheel. The U.S. Navy became an early supporter of radials, which offered reliability along with light weight. This was an important feature if planes were to take off successfully from an aircraft carrier's flight deck.
With financial support from the Navy, two American firms, Wright Aeronautical and Pratt & Whitney, began building air-cooled radials. The Wright Whirlwind, in 1924, delivered 220 horsepower (164 kilowatts). A year later, the Pratt & Whitney Wasp was tested at 410 horsepower (306 kilowatts).

Aircraft designers wanted to build planes that could fly at high altitudes. High-flying planes could swoop down on their enemies and also were harder to shoot down. Bombers and passenger aircraft flying at high altitudes could fly faster because air is thin at high altitudes and there is less drag in the thinner air. These planes also could fly farther on a tank of fuel.

The supercharger, spinning within a closely fitted housing (not shown), pumped additional air into aircraft piston engines.

But because the air was thinner, aircraft engines produced much less power. They needed air to operate, and they couldn't produce power unless they had more air. Designers responded by fitting the engine with a "supercharger." This was a pump that took in air and compressed it. The extra air, fed into an engine, enabled it to continue to put out full power even at high altitude.
A supercharger needed power to operate. This power came from the engine itself. The supercharger, also called a centrifugal compressor, drew air through an inlet. It compressed this air and sent it into the engine. Similar compressors later found use in early jet engines.

Early superchargers underwent tests before the end of World War I, but they were heavy and offered little advantage. The development of superchargers proved to be technically demanding, but by 1930, the best British and American engines installed such units routinely. In the United States, the Army funded work on superchargers at another engine-builder, General Electric. After 1935, engines fitted with GE's superchargers gave full power at heights above 30,000 feet (9,000 meters).

Fuels for aviation also demanded attention. When engine designers tried to build motors with greater power, they ran into the problem of "knock." This had to do with the way fuel burned within them. An airplane engine had a carburettor that took in fuel and air, producing a highly flammable mixture of gasoline vapour with air, which went into the cylinders. There, this mix was supposed to burn very rapidly, but in a controlled manner. Unfortunately, the mixture tended to explode, which damaged engines. The motor then was said to knock.

Poor-grade fuels avoided knock but produced little power. Soon after World War I, an American chemist, Thomas Midgely, determined that small quantities of a suitable chemical added to high-grade gasoline might help it burn without knock. He tried a number of additives and found that the best was tetraethyl lead. The U.S. Army began experiments with leaded aviation fuel as early as 1922; the Navy adopted it for its carrier-based aircraft in 1926. Leaded gasoline became standard as a high-test fuel, used widely in automobiles as well as in aircraft.

The Pratt and Whitney R-1830 Twin Wasp engine was one of the most efficient and reliable engines of the 1930s. It was a "twin-row" engine. Twin-row engines powered the warplanes of World War II.

Leaded gas improved an aircraft engine's performance by enabling it to use a supercharger more effectively while using less fuel. The results were spectacular. The best engine of World War I, the Liberty, developed 400 horsepower (300 kilowatts). In World War II, Britain's Merlin engine was about the same size—and put out 2,200 horsepower (1,640 kilowatts). Samuel Heron, a long-time leader in the development of aircraft engines and fuels, writes that "it is probably true that about half the gain in power was due to fuel."

The V-1650 liquid-cooled engine was the U.S. version of the famous British Rolls-Royce "Merlin" engine which powered the "Spitfire" and "Hurricane" fighters during the Battle of Britain in 1940.
During World War II, the best piston engines used a turbocharger. This was a supercharger that drew its power from the engine' hot exhaust gases. This exhaust had plenty of power, which otherwise would have gone to waste. A turbine tapped this power and drove the supercharger. Similar turbines later appeared in jet engines.

These advances in supercharging and knock-resistant fuels laid the groundwork for the engines of World War II. In 1939, the German test pilot Fritz Wendel flew a piston-powered fighter to a speed record of 469 miles per hour (755 kilometres per hour). U.S. bombers used superchargers to carry heavy bomb loads at 34,000 feet (10,000 meters). They also achieved long range, the B-29 bomber had the range to fly non-stop from Miami to Seattle. Fighters routinely topped 400 miles per hour (640 kilometers per hour). Airliners, led by the Lockheed Constellation, showed that they could fly non-stop from coast to coast.

The Wasp Major engine was developed during World War II though it only saw service late in the war on some B-29 and B-50 aircraft and after the war. It represented the most technically advanced and complex reciprocating engine produced in large numbers in the United States. It was a four-row engine, meaning it had four circumferential rows of cylinders.

By 1945, the jet engine was drawing both attention and excitement. Jet fighters came quickly to the forefront. However, while early jet engines gave dramatic increases in speed, they showed poor fuel economy. It took time before engine builders learned to build jets that could sip fuel rather than gulp it. Until that happened, the piston engine retained its advantage for use in bombers and airliners, which needed to be able to fly a great distance without refuelling.

Pratt & Whitney was the first to achieve high thrust with good fuel economy. Its J-57 engine, which did these things, first ran on a test stand in 1950. Eight such engines powered the B-52, a jet bomber with intercontinental range that entered service in 1954. Civilian versions of this engine powered the Boeing 707 and Douglas DC-8, jet airliners that began carrying passengers in 1958 and 1959, respectively. In this fashion, jet engines conquered nearly the whole of aviation.

活塞式发动机 Piston Engine

2009-04-09T01:53:00.003+08:00

Rolls-Royce 公司生产的最后一款活塞式发动机-- RR Griffon 58

航空活塞式发动机是利用汽油与空气混合，在密闭的容器（气缸）内燃烧，膨胀作功的机械。活塞式发动机必须带动螺旋桨，由螺旋桨产生推（拉）力。所以，作为飞机的动力装置时，发动机与螺旋桨是不能分割的。
　　
（一）活塞式发动机的主要组成　　　主要由气缸、活塞、连杆、曲轴、气门机构、螺旋桨减速器、机匣等组成。
　　
气缸是混合气（汽油和空气）进行燃烧的地方。气缸内容纳活塞作往复运动。气缸头上装有点燃混合气的电火花塞（俗称电嘴），以及进、排气门。发动机工作时气缸温度很高，所以气缸外壁上有许多散热片，用以扩大散热面积。气缸在发动机壳体（机匣）上的排列形式多为星形或V形。常见的星形发动机有5个、7个、9个、14个、18个或24个气缸不等。在单缸容积相同的情况下，气缸数目越多发动机功率越大。活塞承受燃气压力在气缸内作往复运动，并通过连杆将这种运动转变成曲轴的旋转运动。连杆用来连接活塞和曲轴。曲轴是发动机输出功率的部件。曲轴转动时，通过减速器带动螺旋桨转动而产生拉力。除此而外，曲轴还要带动一些附件（如各种油泵、发电机等）。气门机构用来控制进气门、排气门定时打开和关闭。
　　
（二）活塞式发动机的工作原理
　　
活塞顶部在曲轴旋转中心最远的位置叫上死点、最近的位置叫下死点、从上死点到下死点的距离叫活塞冲程。活塞式航空发动机大多是四冲程发动机，即一个气缸完成一个工作循环，活塞在气缸内要经过四个冲程，依次是进气冲程、压缩冲程、膨胀冲程和排气冲程。
　　
发动机开始工作时，首先进入“进气冲程”，气缸头上的进气门打开，排气门关闭，活塞从上死点向下滑动到下死点为止，气缸内的容积逐渐增大，气压降低——低于外面的大气压。于是新鲜的汽油和空气的混合气体，通过打开的进气门被吸入气缸内。混合气体中汽油和空气的比例，一般是 1比 15即燃烧一公斤的汽油需要15公斤的空气。
　　
进气冲程完毕后，开始了第二冲程，即“压缩冲程”。这时曲轴靠惯性作用继续旋转，把活塞由下死点向上推动。这时进气门也同排气门一样严密关闭。气缸内容积逐渐减少，混合气体受到活塞的强烈压缩。当活塞运动到上死点时，混合气体被压缩在上死点和气缸头之间的小空间内。这个小空间叫作“燃烧室”。这时混合气体的压强加到十个大气压。温度也增加到摄氏4OO度左右。压缩是为了更好地利用汽油燃烧时产生的热量，使限制在燃烧室这个小小空间里的混合气体的压强大大提高，以便增加它燃烧后的做功能力。
　　
当活塞处于下死点时，气缸内的容积最大，在上死点时容积最小（后者也是燃烧室的容积）。混合气体被压缩的程度，可以用这两个容积的比值来衡量。这个比值叫“压缩比”。活塞航空发动机的压缩比大约是5到8，压缩比越大，气体被压缩得越厉害，发动机产生的功率也就越大。
　　
压缩冲程之后是“工作冲程”，也是第三个冲程。在压缩冲程快结束，活塞接近上死点时，气缸头上的火花塞通过高压电产生了电火花，将混合气体点燃，燃烧时间很短，大约0.015秒；但是速度很快，大约达到每秒30米。气体猛烈膨胀，压强急剧增高，可达6O到75个大气压，燃烧气体的温度到摄氏2000到250O度。燃烧时，局部温度可能达到三、四千度，燃气加到活塞上的冲击力可达15吨。活塞在燃气的强大压力作用下，向下死点迅速运动，推动连杆也门下跑，连杆便带动曲轴转起来了。
　　
这个冲程是使发动机能够工作而获得动力的唯一冲程。其余三个冲程都是为这个冲程作准备的。
　　
第四个冲程是“排气冲程”。工作冲程结束后，由于惯性，曲轴继续旋转，使活塞由下死点向上运动。这时进气门仍旧关闭，而排气门大开，燃烧后的废气便通过排气门向外排出。当活塞到达上死点时，绝大部分的废气已被排出。然后排气门关闭，进气门打开，活塞又由上死点下行，开始了新的一次循环。
　　
从进气冲程吸入新鲜混合气体起，到排气冲程排出废气止，汽油的热能通过燃烧转化为推动活塞运动的机械能，带动螺旋桨旋转而作功，这一总的过程叫做一个“循环”。这是一种周而复始的运动。由于其中包含着热能到机械能的转化，所以又叫做“热循环”。
　　
活塞航空发动机要完成四冲程工作，除了上述气缸、活塞、联杆、曲轴等构件外，还需要一些其他必要的装置和构件。
　　
（三）活塞式航空发动机的辅助工作系统
　　
发动机除主要部件外，还须有若干辅助系统与之配合才能工作。主要有进气系统（为了改善高空性能，在进气系统内常装有增压器，其功用是增大进气压力）、燃油系统、点火系统（主要包括高电压磁电机、输电线、火花塞）、起动系统（一般为电动起动机）、散热系统和润滑系统等。

渦輪扇葉發動機 Turbofan Engine

2009-04-08T18:45:00.007+08:00

渦輪扇葉發動機（Turbofan Engine，亦稱渦扇發動機、渦輪扇發動機）是航空發動機的一種，由渦輪噴射發動機（Turbojet，簡稱渦噴發動機）發展而成。

與渦噴比較，主要特點是其首級壓縮扇葉的面積大很多，除了作為壓縮空氣的用途之外，同時也具有螺旋槳的作用，能將部分吸入的空氣通過噴射發動機的外圍向後推。發動機核心部分空氣經過的部分稱為內進氣道，僅有風扇空氣經過的核心機外側部分稱為外進氣道。

渦扇引擎最適合飛行速度為每小時400至2,000公里時使用，故此現在多數的噴射機引擎都是採用渦扇發動機作為動力來源。

渦扇引擎的旁通比（Bypass ratio）是單位時間內不經過燃燒室的空氣質量，與通過燃燒室的空氣質量的比例。旁通比為零的渦扇引擎即是渦輪噴射發動機。早期的渦扇引擎和現代戰鬥機使用的渦扇引擎旁通比都較低。例如世界上第一款渦扇引擎，勞斯萊斯的Conway，其旁通比只有0.3。現代多數民航機引擎的旁通比通常都在5以上。旁通比高的渦輪扇引擎耗油較少，但推力卻與渦輪噴射發動機相當，且運轉時還寧靜得多。

戰鬥機使用低旁通比發動機，主要是因為截面積與常用飛行速度，高旁通比的發動機，截面積過大在超音速的時候阻力過大，另外在超音速的狀況下效率也會比純渦輪射噴甚至於低旁通還低，所以戰鬥機皆使用低旁通比發動機(旁通比皆低於1)，另外還有像是SR-71使用可變旁通比發動機，能夠關閉旁通部份，來增加超音速的效率，像是只在超音速飛行的協和號噴射客機，因為長時間處於超音速狀態，為了提昇效率與降低成本就是使用純渦輪噴射而無旁通比的發動機。

主要組成部分

進氣道
風扇
低壓壓縮機（Low pressure compressor）
高壓壓縮機（High pressure compressor）
燃燒室
高壓渦輪（High pressure turbine）
低壓渦輪（Low pressure turbine）
後燃器（Afterburner，是一選用機構，較常見於高性能的戰鬥機上）
噴嘴（Nozzel）

A turbofan is a type of aircraft engine consisting of a ducted fan which is powered by a gas turbine. Part of the airstream from the ducted fan passes through the gas turbine core, providing oxygen to burn fuel to create power. However, most of the air flow bypasses the engine core, and is accelerated by the fan blades in much the same manner as a propeller.

The combination of thrust produced from the fan and the exhaust from the core is a more efficient process than other jet engine designs, resulting in a comparatively low specific fuel consumption.

A few designs work slightly differently and have the fan blades as a radial extension of an aft-mounted low-pressure turbine unit.

Turbofans have a net exhaust speed that is much lower than a turbojet. This makes them much more efficient at subsonic speeds than turbojets, and somewhat more efficient at supersonic speeds up to roughly Mach 1.6, but have also been found to be efficient when used with continuous afterburner at Mach 3 and above.

All of the jet engines used in currently manufactured commercial jet aircraft are turbofans. They are used commercially mainly because they are highly efficient and relatively quiet in operation. Turbofans are also used in many military jet aircraft.

Stationary components

1. Nacelle

2. Fan

3. Low pressure compressor

4. High pressure compressor

5. Combustion chamber

6. High pressure turbine

7. Low pressure turbine

8. Core nozzle

9. Fan nozzle

自从惠特尔发明了第一台涡轮喷气发动机以后，涡轮喷气发动机很快便以其强大的动力、优异的高速性能取代了活塞式发动机，成为战斗机的首选动力装置，并开始在其他飞机中开始得到应用。
　　

但是，随着喷气技术的发展，涡轮喷气发动机的缺点也越来越突出，那就是在低速下耗油量大，效率较低，使飞机的航程变得很短。尽管这对于执行防空任务的高速战斗机还并不十分严重，但若用在对经济性有严格要求的亚音速民用运输机上却是不可接受的。
　　

要提高喷气发动机的效率，首先要知道什么式发动机的效率。发动机的效率实际上包括两个部分，即热效率和推进效率。为提高热效率，一般来讲需要提高燃气在涡轮前的温度和压气机的增压比，但在飞机的飞行速度不变的情况下，提高涡轮前温度将会使喷气发动机的排气速度增加，导致在空气中损失的动能增加，这样又降低了推进效率。由于热效率和推进效率对发动机循环参数矛盾的要求，致使涡轮喷气发动机的总效率难以得到较大的提升。
　　

那么，如何才能同时提高喷气发动机的热效率和推进效率，也就是怎样才能既提高涡轮前温度又至少不增加排气速度呢？答案就是采用涡轮风扇发动机。这种发动机在涡轮喷气发动机的的基础上增加了几级涡轮，并由这些涡轮带动一排或几排风扇，风扇后的气流分为两部分，一部分进入压气机（内涵道），另一部分则不经过燃烧，直接排到空气中（外涵道）。

由于涡轮风扇发动机一部分的燃气能量被用来带动前端的风扇，因此降低了排气速度，提高了推进效率，而且，如果为提高热效率而提高涡轮前温度后，可以通过调整涡轮结构参数和增大风扇直径，使更多的燃气能量经风扇传递到外涵道，就不会增加排气速度。这样，对于涡轮风扇发动机来讲，热效率和推进效率不再矛盾，只要结构和材料允许，提高涡轮前温度总是有利的。
　　

目前航空用涡轮风扇发动机主要分两类，即不加力式涡轮风扇发动机和加力式涡轮风扇发动机。前者主要用于高亚音速运输机，后者主要用于歼击机，由于用途不同，这两类发动机的结构参数也大不相同。　
　　

不加力式涡轮风扇发动机不仅涡轮前温度较高，而且风扇直径较大，涵道比可达8以上，这种发动机的经济性优于涡轮喷气发动机，而可用飞行速度又比活塞式发动机高，在现代大型干线客机、军用运输机等最大速度为M0.9左右的飞机中得到广泛的应用。根据热机的原理，当发动机的功率一定时，参加推进的工质越多，所获得的推力就越大，不加力式涡轮风扇发动机由于风扇直径大，空气流量就大，因而推力也较大。同时由于排气速度较低，这种发动机的噪音也较小。
　　

加力式涡轮风扇发动机在飞机巡航中是不开加力的，这时它相当于一台不加力式涡轮风扇发动机，但为了追求高的推重比和减小阻力，这种发动机的涵道比一般在1.0以下。在高速飞行时，发动机的加力打开，外涵道的空气和涡轮后的燃气一同进入加力燃烧室喷油后再次燃烧，使推力可大幅度增加，甚至超过了加力式涡轮喷气发动机，而且随着速度的增加，这种发动机的加力比还会上升，并且耗油率有所下降。加力式涡轮风扇发动机由于具有这种低速时较油耗低，开加力时推重比大的特点，目前已在新一代歼击机上得到广泛应用。

渦輪噴射發動機 Turbojet Engine

2009-04-08T18:03:00.006+08:00

渦輪噴射發動機(Turbojet)（簡稱渦噴發動機）是一種渦輪發動機。特點是完全依賴燃氣流產生推力。通常用作高速飛機的動力。油耗比渦輪扇葉發動機高。

渦噴發動機分為離心式與軸流式兩種，離心式由英國人弗蘭克·惠特爾爵士於1930年取得發明專利，但是直到1941年裝有這種發動機的飛機才第一次上天，沒有參加第二次世界大戰，軸流式誕生在德國，並且作為第一種實用的噴射式戰鬥機Me-262的動力參加了1944年末的戰鬥。

相比起離心式渦噴發動機，軸流式具有橫截面小，壓縮比高的優點，但是需要較高品質的材料——這在1945年左右是不存在的。當今的渦噴發動機均為軸流式。

Turbojets are the oldest kind of general purpose jet engines. Two engineers, Frank Whittle in the United Kingdom and Hans von Ohain in Germany, developed the concept independently into practical engines during the late 1930s, although credit for the first turbojet is given to Whittle who submitted the first proposal and held a UK patent that was widely read.

Turbojets consist of an air inlet, an air compressor, a combustion chamber, a gas turbine (that drives the air compressor) and a nozzle. The air is compressed into the chamber, heated and expanded by the fuel combustion and then allowed to expand out through the turbine into the nozzle where it is accelerated to high speed to provide propulsion.

Turbojets are quite inefficient (if flown below about Mach 2) and very noisy. Most modern aircraft use turbofans instead for economic reasons. Turbojets are still very common in medium range cruise missiles,[citation needed] due to their high exhaust speed, low frontal area and relative simplicity.

在第二次世界大战以前，所有的飞机都采用活塞式发动机作为飞机的动力，这种发动机本身并不能产生向前的动力，而是需要驱动一副螺旋桨，使螺旋桨在空气中旋转，以此推动飞机前进。这种活塞式发动机＋螺旋桨的组合一直是飞机固定的推进模式，很少有人提出过质疑。
　　

到了三十年代末，尤其是在二战中，由于战争的需要，飞机的性能得到了迅猛的发展，飞行速度达到700－800公里每小时，高度达到了10000米以上，但人们突然发现，螺旋桨飞机似乎达到了极限，尽管工程师们将发动机的功率越提越高，从1000千瓦，到2000千瓦甚至3000千瓦，但飞机的速度仍没有明显的提高，发动机明显感到“有劲使不上”。
　　

问题就出在螺旋桨上，当飞机的速度达到800公里每小时，由于螺旋桨始终在高速旋转，桨尖部分实际上已接近了音速，这种跨音速流场的直接后果就是螺旋桨的效率急剧下降，推力下降，同时，由于螺旋桨的迎风面积较大，带来的阻力也较大，而且，随着飞行高度的上升，大气变稀薄，活塞式发动机的功率也会急剧下降。这几个因素合在一起，决定了活塞式发动机＋螺旋桨的推进模式已经走到了尽头，要想进一步提高飞行性能，必须采用全新的推进模式，喷气发动机应运而生。
　　

喷气推进的原理大家并不陌生，根据牛顿第三定律，作用在物体上的力都有大小相等方向相反的反作用力。喷气发动机在工作时，从前端吸入大量的空气，燃烧后高速喷出，在此过程中，发动机向气体施加力，使之向后加速，气体也给发动机一个反作用力，推动飞机前进。事实上，这一原理很早就被应用于实践中，我们玩过的爆竹，就是依靠尾部喷出火药气体的反作用力飞上天空的。
　　

早在1913年，法国工程师雷恩．洛兰就获得了一项喷气发动机的专利，但这是一种冲压式喷气发动机，在当时的低速下根本无法工作，而且也缺乏所需的高温耐热材料。1930年，弗兰克．惠特尔取得了他使用燃气涡轮发动机的第一个专利，但直到11年后，他的发动机在完成其首次飞行，惠特尔的这种发动机形成了现代涡轮喷气发动机的基础。
　　

现代涡轮喷气发动机的结构由进气道、压气机、燃烧室、涡轮和尾喷管组成，战斗机的涡轮和尾喷管间还有加力燃烧室。涡轮喷气发动机仍属于热机的一种，就必须遵循热机的做功原则：在高压下输入能量，低压下释放能量。因此，从产生输出能量的原理上讲，喷气式发动机和活塞式发动机是相同的，都需要有进气、加压、燃烧和排气这四个阶段，不同的是，在活塞式发动机中这4个阶段是分时依次进行的，但在喷气发动机中则是连续进行的，气体依次流经喷气发动机的各个部分，就对应着活塞式发动机的四个工作位置。
　　

空气首先进入的是发动机的进气道，当飞机飞行时，可以看作气流以飞行速度流向发动机，由于飞机飞行的速度是变化的，而压气机适应的来流速度是有一定的范围的，因而进气道的功能就是通过可调管道，将来流调整为合适的速度。在超音速飞行时，在进气道前和进气道内气流速度减至亚音速，此时气流的滞止可使压力升高十几倍甚至几十倍，大大超过压气机中的压力提高倍数，因而产生了单靠速度冲压，不需压气机的冲压喷气发动机。
　　

进气道后的压气机是专门用来提高气流的压力的，空气流过压气机时，压气机工作叶片对气流做功，使气流的压力，温度升高。在亚音速时，压气机是气流增压的主要部件。
　　

从燃烧室流出的高温高压燃气，流过同压气机装在同一条轴上的涡轮。燃气的部分内能在涡轮中膨胀转化为机械能，带动压气机旋转，在涡轮喷气发动机中，气流在涡轮中膨胀所做的功正好等于压气机压缩空气所消耗的功以及传动附件克服摩擦所需的功。经过燃烧后，涡轮前的燃气能量大大增加，因而在涡轮中的膨胀比远小于压气机中的压缩比，涡轮出口处的压力和温度都比压气机进口高很多，发动机的推力就是这一部分燃气的能量而来的。
　　

从涡轮中流出的高温高压燃气，在尾喷管中继续膨胀，以高速沿发动机轴向从喷口向后排出。这一速度比气流进入发动机的速度大得多，使发动机获得了反作用的推力。
　　

一般来讲，当气流从燃烧室出来时的温度越高，输入的能量就越大，发动机的推力也就越大。但是，由于涡轮材料等的限制，目前只能达到1650K左右，现代战斗机有时需要短时间增加推力，就在涡轮后再加上一个加力燃烧室喷入燃油，让未充分燃烧的燃气与喷入的燃油混合再次燃烧，由于加力燃烧室内无旋转部件，温度可达2000K，可使发动机的推力增加至1.5倍左右。其缺点就是油耗急剧加大，同时过高的温度也影响发动机的寿命，因此发动机开加力一般是有时限的，低空不过十几秒，多用于起飞或战斗时，在高空则可开较长的时间。
　　

随着航空燃气涡轮技术的进步，人们在涡轮喷气发动机的基础上，又发展了多种喷气发动机，如根据增压技术的不同，有冲压发动机和脉动发动机；根据能量输出的不同，有涡轮风扇发动机、涡轮螺旋桨发动机、涡轮轴发动机和螺桨风扇发动机等。
　　

喷气发动机尽管在低速时油耗要大于活塞式发动机，但其优异的高速性能使其迅速取代了后者，成为航空发动机的主流。

渦輪螺旋槳發動機 Turboprop Engines

2009-04-08T17:58:00.005+08:00

渦輪螺旋槳發動機（Turboprop Engines，或根據其發動機類型而稱為渦輪螺旋槳噴射發動機，並常簡稱為渦槳發動機,是一種通常用於飛機上的燃氣渦輪發動機（gas turbine engine）。

渦槳發動機的驅動原理大致上與使用活塞發動機作為動力來源的傳統螺旋槳飛機雷同，是以螺旋槳旋轉時所產生的力量來作為飛機前進的推進力。其與活塞式螺槳機主要的差異點除了驅動螺旋槳中心軸的動力來源不同外，還有就是渦槳發動機的螺旋槳通常是以恆定的速率運轉，而活塞動力的螺旋槳則會依照發動機的轉速不同而有轉速高低的變化。

雖然渦槳發動機的燃燒室與渦輪噴射發動機類似，但為了自排廢氣中回收較多的動力以驅動螺旋槳，渦槳引擎的渦輪（Turbine）端之扇葉級數比較高。相反的，由於渦輪噴射發動機主要的推進力都來自於熱氣直接排放至大氣中所產生的反作用力，因此其渦輪端的扇葉級距數越小越好，只需保持足夠的回收動力用來驅動壓縮端的扇葉即可。

事實上，渦槳發動機的效率亦高於渦輪風扇發動機，但是使用渦槳引擎的飛機速度通常較渦輪風扇發動機的飛機來的低。原因是渦槳引擎的旁通比通常比渦輪風扇引擎來的高，但是也造成其槳葉端部分速度很高，有產生震波的可能。另外，因渦輪轉動速度很快，使得渦輪與螺槳之間必須要有變速齒輪，來降低螺槳轉速使其葉端不要超過音速。所以使用螺槳發動機的飛機會多個變速齒輪的重量。

雖然渦輪螺旋槳發動機常用在較小型或較低速的次音速飛機上，但也有少數使用渦輪螺旋槳發動機的飛機，可以以非常接近音速的500節（約926公里/小時，或575英里/小時）的空速在空中巡航，例如蘇聯/俄羅斯空軍的Tu-95和海軍航空兵的Tu-142四發重型飛機。

A turboprop engine is a type of aircraft powerplant that uses a gas turbine to drive a propeller. The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller. The engine's exhaust gases contain little energy compared to a jet engine and play a minor role in the propulsion of the aircraft.

The propeller is coupled to the turbine through a reduction gear that converts the high RPM, low torque output to low RPM, high torque. The propeller itself is normally a constant speed (variable pitch) type similar to that used with larger reciprocating aircraft engines.

Currently, turboprop engines are generally used on small subsonic aircraft, but some aircraft outfitted with turboprops have cruising speeds in excess of 500 kt (926 km/h, 575 mph). Large military and civil aircraft, such as the Lockheed L-188 Electra, have also used turboprop power.
In its simplest form, a turboprop consists of an intake, compressor, combustor, turbine and a propelling nozzle. Air is drawn into the intake and compressed by the compressor.

Fuel is then added to the compressed air in the combustor, where the fuel-air mixture then combusts. The hot combustion gases expand through the turbine. Some of the power generated by the turbine is used to drive the compressor. The rest is transmitted through the reduction gearing to the propeller. Further expansion of the gases occurs in the propelling nozzle, where the gases exhaust to atmospheric pressure. The propelling nozzle provides a relatively small proportion of the thrust generated by a turboprop.

Turboprops are very efficient at modest flight speeds (below 450 mph) because the jet velocity of the propeller (and exhaust) is relatively low. Due to the high price of turboprop engines, they are mostly used where high-performance short-takeoff and landing (STOL) capability and efficiency at modest flight speeds are required. In a civilian aviation context, the most common application of turboprop engines is in small commuter aircraft, where their greater reliability as compared to reciprocating engines offsets their higher initial cost.

一般来说，现代不加力涡轮风扇发动机的涵道比是有着不断加大的趋势的。因为对于涡轮风扇发动机来说，若飞行速度一定，要提高飞机的推进效率，也就是要降低排气速度和飞行速度的差值，需要加大涵道比；而同时随着发动机材料和结构工艺的提高，许用的涡轮前温度也不断提高，这也要求相应地增大涵道比。对于一架低速（500～600km/h）的飞机来说，在一定的涡轮前温度下，其适当的涵道比应为50以上，这显然是发动机的结构所无法承受的。
　　

为了提高效率，人们索性便抛去了风扇的外涵壳体，用螺旋桨代替了风扇，便形成了涡轮螺旋桨发动机，简称涡桨发动机。涡轮螺旋桨发动机由螺旋桨和燃气发生器组成，螺旋桨由涡轮带动。由于螺旋桨的直径较大，转速要远比涡轮低，只有大约1000转/分，为使涡轮和螺旋桨都工作在正常的范围内，需要在它们之间安装一个减速器，将涡轮转速降至十分之一左右后，才可驱动螺旋桨。这种减速器的负荷重，结构复杂，制造成本高，它的重量一般相当于压气机和涡轮的总重，作为发动机整体的一个部件，减速器在设计、制造和试验中占有相当重要的地位。
　　

涡轮螺旋桨发动机的螺旋桨后的空气流就相当于涡轮风扇发动机的外涵道，由于螺旋桨的直径比发动机大很多，气流量也远大于内涵道，因此这种发动机实际上相当于一台超大涵道比的涡轮风扇发动机。
　　

尽管工作原理近似，但涡轮螺旋桨发动机和涡轮风扇发动机在产生动力方面却有着很大的不同，涡轮螺旋桨发动机的主要功率输出方式为螺旋桨的轴功率，而尾喷管喷出的燃气推力极小，只占总推力的5%左右，为了驱动大功率的螺旋桨，涡轮级数也比涡轮风扇发动机要多，一般为2～6级。
　　

同活塞式发动机＋螺旋桨相比，涡轮螺旋桨发动机有很多优点。首先，它的功率大，功重比（功率/重量）也大，最大功率可超过10000马力，功重比为4以上；而活塞式发动机最大不过三四千马力，功重比2左右。其次，由于减少了运动部件，尤其是没有做往复运动的活塞，涡轮螺旋桨发动机运转稳定性好，噪音小，工作寿命长，维修费用也较低。而且，由于核心部分采用燃气发生器，涡轮螺旋桨发动机的适用高度和速度范围都要比活塞式发动机高很多。在耗油率方面，二者相差不多，但涡轮螺旋桨发动机所使用的煤油要比活塞式发动机的汽油便宜。
　　

由于涵道比大，涡轮螺旋桨发动机在低速下效率要高于涡轮风扇发动机，但受到螺旋桨效率的影响，它的适用速度不能太高，一般要小于900km/h。目前在中低速飞机或对低速性能有严格要求的巡逻、反潜或灭火等类型飞机中的到广泛应用。

渦輪發動機 Turbine Engine

2009-04-08T17:50:00.004+08:00

渦輪可以小到在車輛引擎內部，也能大到數公尺的發電廠用渦輪。圖為發電廠使用的渦輪。

渦輪發動機（Turbine engine，或常簡稱為渦輪，Turbine）是一種利用旋轉的機件自穿過它的流體中汲取動能的發動機形式。經常在飛機與大型的船舶或車輛上看到其應用。

雖然渦輪發動機可能有許多不同的運作原理，但最簡單的渦輪型式可以只包含一個「轉子」（Rotor），例如一個帶有中心軸的扇葉，將此扇葉放置在流體中（例如空氣或水），流體通過時對扇葉施加的力量會帶動整個轉子開始轉動，進而得以從中心軸輸出軸向的扭力。風車與水車這類的裝置，可以說是人類最早發明的渦輪發動機原型。

依照不同的分類方式，渦輪發動機也可以分類成很多不同的型式。例如以燃燒室與轉子的位置是否在一起來區別，就存在有屬於外燃機一類的蒸汽渦輪發動機，與屬於內燃機的燃氣渦輪發動機。
如果將渦輪發動機反過來運作，則會變成一種輸入力量之後可以將流體帶動的設備，例如壓縮機（compressor）與幫浦（pump，又稱為「泵」）。

有些渦輪發動機本身具有多組扇葉，其中部分是用於自流體汲取動力，部分是用於推動流體，二者不能混為一談。舉例來說在大部分的渦輪扇葉發動機與渦輪螺旋槳發動機中，位於燃燒室之前的扇葉實際的作用是用於加壓進氣，因此應被視為是一種壓縮機。真正的渦輪機部分是位於燃燒室後方的風扇，被燃燒後的排氣推動產生動力，再透過傳動軸將力量輸送至主扇葉（渦輪扇葉發動機）或螺旋槳（渦輪輪懸槳發動機）處，推動其運轉。

A turbine is a rotary engine that extracts energy from a fluid flow. Claude Burdin (1788-1873) coined the term from the Latin turbo, or vortex, during an 1828 engineering competition. Benoit Fourneyron (1802-1867), a student of Claude Burdin, built the first practical water turbine.

The simplest turbines have one moving part, a rotor assembly, which is a shaft with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they rotate and impart energy to the rotor. Early turbine examples are windmills and water wheels.

Gas, steam, and water turbines usually have a casing around the blades that contains and controls the working fluid. Credit for invention of the modern steam turbine is given to British Engineer Sir Charles Parsons (1854 - 1931).

A device similar to a turbine but operating in reverse is a compressor or pump. The axial compressor in many gas turbine engines is a common example.

渦輪軸發動機 Turboshaft Engine

2009-04-08T17:44:00.005+08:00

渦輪軸發動機(Turboshaft)，是渦輪發動機的一種，利用燃燒室產生的氣流帶動自由渦輪輸出軸功率，而不是噴氣推力。結構上類似於坦克、水翼船等。

最早由法國引擎製造商Turbomeca于1948年設計製造。

A turboshaft engine is a form of gas turbine which is optimized to produce shaft power, rather than jet thrust. In principle a turboshaft engine is similar to a turbojet, except the former features additional turbine expansion to extract heat energy from the exhaust and convert it into output shaft power.

Turboshaft engines are commonly used in applications which require a sustained high power output, high reliability, small size and light weight. These include helicopters, auxiliary power units, boats and ships, tanks, hovercraft, and sometimes stationary equipment.

Overview

A turboshaft engine contains a gas generator section, consisting of the compressor, combustion chambers with ignitors and fuel nozzles, and one or more stages of turbine. The gas generator's function is to create the hot expanding gases to drive the power section, which consists of more stages of turbines, a gear reduction system, and shaft output. Depending on the design, the engine accessories may be driven either by the gas generator or by the power section.

In most designs the gas generator and power section are mechanically separate so that they may each rotate at different speeds appropriate for the conditions. This is referred to as a free power turbine. A free power turbine can be an extremely useful design feature for vehicles, as it allows the design to forego the weight and cost of complex multi-ratio transmissions and clutches.

The general layout of a turboshaft is similar to that of a turboprop. The main difference is that a turboprop is structurally designed to support the loads created by a rotating propeller, as the propeller is not attached to anything but the engine itself. In contrast, turboshaft engines usually drive a transmission which is not structurally attached to the engine.

The transmission is attached to the vehicle structure and supports the loads created instead of the engine. However, in practice many of the same engines are built in both turboprop and turboshaft versions, with only minor differences.

History

The first true turboshaft engine was built by the French engine firm Turbomeca, led by the founder, Joseph Szydlowski. In 1948 they built the first French-designed turbine engine, the 100shp 782. In 1950 this work was used to develop the larger 280shp Artouste, which was widely used on the Aérospatiale Alouette II and other helicopters.

在带有压气机的涡轮发动机这一类型中，涡轮轴发动机出现得较晚，但已在直升机和垂直／短距起落飞机上得到了广泛的应用。
　

涡轮轴发动机于1951年12月开始装在直升机上，作第一次飞行。那时它属于涡轮螺桨发动机，并没有自成体系。以后随着直升机在军事和国民经济上使用越来越普遍，涡轮轴发动机才获得独立的地位。
　　

在工作和构造上，涡轮轴发动机同涡轮螺桨发动机根相近。它们都是由涡轮风扇发动机的原理演变而来，只不过后者将风扇变成了螺旋桨，而前者将风扇变成了直升机的旋翼。除此之外，涡轮轴发动机也有自己的特点：它一般装有自由涡轮(即不带动压气机，专为输出功率用的涡轮)，而且主要用在直升机和垂直／短距起落飞机上。
　　

在构造上，涡轮轴发动机也有进气道、压气机、燃烧室和尾喷管等燃气发生器基本构造，但它一般都装有自由涡轮，如图所示，前面的是两级普通涡轮，它带动压气机，维持发动机工作，后面的二级是自由涡轮，燃气在其中作功，通过传动轴专门用来带动直升机的旋翼旋转，使它升空飞行。

此外，从涡轮流出来的燃气，经过尾喷管喷出，可产生一定的推力，由于喷速不大，这种推力很小，如折合为功率，大约仅占总功率的十分之一左右。有时喷速过小，甚至不产生什么推力。为了合理地安排直升机的结构，涡轮轴发动机的喷口，可以向上，向下或向两侧，不象涡轮喷气发动机那样非向后不可。这有利于直升机设计时的总体安排。
　　

涡轮轴发动机是用于直升机的，它与旋翼配合，构成了直升机的动力装置。按照涡轮风扇发动机的理论，从理论上讲，旋翼的直径愈大愈好。同样的核心发动机，产生同样的循环功率，所配合的旋翼直径愈大，则在旋翼上所产生的升力愈大。事实上，由于在能量转换过程中有损失，旋翼也不可能制成无限大，所以，旋翼的直径是有限制的。——般说，通过旋翼的空气流量是通过涡轮轴发动机的空气流量的500-1000倍。
　　

同涡轮轴发动机和直升机常用的另一种动力装置——活塞发动机采相比，涡轮轴发动机的功率重量比要大得多，在2.5以上。而且就发动机所产生的功率来说，涡轮轴发动机也大得多，目前使用中的涡轮轴发动机所产生的功率，最高可达6000马力甚至10000马力，活塞发动则相差很远。

在经济性上，涡轮轴发动机的耗油率略高于最好的活塞式发动机，但它所用的航空煤油要比前者所用的汽油便宜，这在一定程度上得到了弥补。当然，涡轮轴发动机也有其不足之处。它制造比较困难，制造成本也较高。特别是由于旋翼的转速更低，它需要比涡轮螺旋桨发动机更重更大的减速齿轮系统，有时它的重量竟占发动机总重量一半以上。　

认识飞机的高度表

2009-04-06T23:24:00.003+08:00

前言
　　
近代的飞机提供给飞行员的信息是愈来愈多，诸如飞机的速度、高度、飞机的姿态、航向、方位、飞机现在的位置、现在的时间、发动机的转速、温度、燃油的存量、以及气象数据等等，可以说是能想到的都有了，不过在这些信息当中，要以速度、高度以及飞机的姿态为最基本的要求。

某架飞机在飞行时与其它飞机的安全间隔距离，以及它与地形地物、建筑、凸出物等的安全间隔距离，均靠高度表所显示的高度作为参考。可惜的是高度表所显示的高度并非真正的高度，因此必须充分了解高度表的构造和原理，方可正确使用高度读数，以避免导致发生危险状况。

这也是为什么近代飞机的驾驶舱内虽然有高科技的航电液晶屏幕，可以切换显示各种信息，并进一步简化了仪表板(少了一大堆指针或小灯泡)，但是传统的速度表、高度表以及姿态仪仍是必须的备份仪表。本文主要目的是以较浅显的文字来说明较复杂的高度表，以及不同的高度定义是如何运用在飞行规则中，同时也看看美国联邦航空法规对高度表有哪些重要规定。
　　
大气特性
　　
在介绍高度表之前，必须先简单了解地球大气的特性。围绕在地球四周的大气有下列两个特性：
　　
1、大气的温度随高度增加而降低。
　　
2、大气的压力因地心引力的关系亦高度的增高而降低。
　　
不过天气的状况每天不一样，温度、压力虽因高度的增加而递减，但三者之间并没有一个常规不变的公式可作为参考。为了有一个共同依据，因此就假设了一组理想值作为压力、温度与高度三者之间的关系，这组数值就称为国际标准大气，简称ISA：

高度(英尺) 压力(英寸汞柱) 温度(摄氏)
16,000 16.21 -17
15,000 16.88 -15
14,000 17.57 -13
13,000 18.29 -11
12,000 19.03 -9
11,000 19.79 -7
10,000 20.58 -5
9,000 21.38 -3
8,000 22.22 -1
7,000 23.09 1

6,000 23.98 3
5,000 24.89 5
4,000 25.84 7
3,000 26.81 9
2,000 27.82 11
1,000 28.86 13
海平面 29.92 15
　
从上表中，你可以发现在海平面(高度为0)时的压力为29.92英寸汞柱高，而温度为摄氏15度。此外，高度每升高1,000英尺，温度降低摄氏两度；高度在7,000英尺之下时，每升高1,000英尺，压力几乎降低1英寸汞柱高。要提醒你的是这仅是一个假设的状况，很少有实际的天气状况是符合这组数值的。你如果有注意每天的天气预报，每个地点的大气压力和温度常常是在改变的。
　　
高度表的种类
　　
一般而言，高度表有两种，一为机械式的压力高度表，另一为较精准的无线电/雷达高度表。压力高度表顾名思义就是利用前述的国际标准大气压力与高度的关系，只要设法量测到大气的压力，高度便可以知道了。它的机械原理是利用一个在受到力量时会收缩或膨胀的微小金属膜盒，将它放置在一个较大的密封盒中，而这个较大的盒子有一个开口，大气的压力经由皮托管或飞机的静压口可通到这个开口进入较大的盒中，(这个较大的盒子实际上即为这个高度表的壳子)，如果外界的大气压力有所改变(高度增加或减少)，这个金属膜盒因此产生收缩或膨胀，而收缩或膨胀的量再经由机械齿轮原理，依照国际标准大气压力与高度的关系传动至高度表的指针，飞行员再读取指针所显示的高度值。因为这种高度表为利用国际标准大气的压力与高度关系，除非你是在国际标准大气情况下飞行，高度表所量出的高度才会等于真正的飞行高度，但是这种情况真是少之又少。
　　
此类的压力表通常尚有一个功能，称为压力调拨值，它最主要的目的是在非国际标准大气压力状况下，让高度表显示出以另一个压力面作为量测起点的高度值。举个例子，若有一个高度表是依照前述国际标准大气压力与高度的关系制成的，把压力调拨值设定在29.92英寸汞柱高，若你在甲机场起飞，甲机场的标高为0高度(海平面高度)，当时机场的大气压力刚好符合国际标准大气状况(29.92英寸汞柱高)，这个时候你在跑道头看你的高度表，其指针显示的指示高度为0英尺。

你飞行一段距离后降落在乙机场，它的标高为1000英尺，若乙机场的大气压力也正好符合国际标准大气状况，这个时候你的高度表就会侦测到乙机场的大气压力为28.86英寸汞柱高，你落地后看你的高度表，其指针显示的指示高度为1,000英尺！亦即海平面之上1,000英尺。

现在假设乙机场的大气压力不再是国际标准大气状况，由28.86英寸汞柱高降至27.82英寸汞柱高，这个时候你的高度表指针显示的指示高度为2,000英尺，不再是正确的1,000英尺！言外之意，在乙机场落地后你的高度表显示出来比跑道真正的高度要高出1,000英尺，这难道不是一件不好的事情吗？这个时候压力调拨值便发挥功能了，它有办法让你的高度表显示出正确的高度值，只要把压力调拨值设定在机场的大气压力即可。

其机械原理很简单，当你改变压力调拨值时，亦改变了金属膜盒大小，同时亦让高度表的指针有所改变，而且两者均依照高度每改变1,000英尺，压力改变1英寸汞柱高的比例来变动。

再举一个例子，如果你在标高为1000英尺的乙机场，高度表的压力调拨值先设在标准的29.92英寸汞柱高，并且注意到高度表的指示高度为1,300英尺，显然高度表的指示高度与机场真实高度有300英尺的误差，解决的方式便是把压力调拨值拨到29.62英寸，(每减少0.1英寸汞柱高，代表100英尺的高度变化)，高度表的指示便回到1,000英尺了。
　　
还有，压力高度表显示的高度是以压力调拨值为量测起点的高度，如果你在乙机场的上空飞行，高度表的指示高度为15,000英尺，表示你在海平面上方15,000英尺的高度飞行，由于乙机场的高度为1,000英尺，你离乙机场的高度只有14,000英尺。
　　
无线电/雷达高度表的原理为经由飞机上发射一束电波，这个电波到达地面后被地面反射回到飞机，在测量所花费的时间之后，便可以利用电波速度和时间算出与地面的高度。
　　
高度定义
　　
有些读者或许会问，怎么一会儿高度是15,000英尺，一会儿又是14,000英尺，飞机还在原在位置没动呢。由于地球表面除了海平面之外，其它的地方或许是高山、平原、深谷、高原、湖泊等等，它们都不见得是海平面高度。当我们说高度的定义时，必须说明是从哪个基准面开始计算，常用的基准面有三种：一为海平面，一为地表面，另一为标准参考面。前两种无须多加解释，第三种是一个理论上的基准面，具体而言就是29.92英寸汞柱高的压力面。在了解压力高度表以及高度的基准面之后，就可以再来看看不同的高度定义以及它们的用途：
　　
1、指示高度：由压力高度表所显示出来的高度，基准面为海平面，但是压力调拨值为当地大气压力值。英文中常用平均海平面的缩写MSL来表示指示高度的基准面。例如：你在台北中正机场上空飞行，就把中正机场的大气压力值定为压力调拨值；若在上海浦东机场上空飞行，就把浦东机场的大气压力值定为压力调拨值。再以美国为例，在18,000英尺以下的仪表飞行规则的空域高度分配以指示高度为准，因此在美境内长途飞行时，飞行员必须注意收听航管中心的广播，航管中心会持续播报各地方的大气压力值，当飞机通过定点时，就把当地的大气压力值定为压力调拨值。
　　
2、压力高度：由压力高度表所显示出来的高度，基准面为标准参考面，也就是压力调拨值不论是在那里都设定为29.92英寸汞柱高。以美国为例，美国联邦航空法规要求若在18,000英尺以上的高度飞行，必须是仪表飞行规则，同时规定压力高度表的压力调拨值须设定在29.92英寸汞柱高。虽然在这种情况下所显示的高度不是真实的飞行高度，但是所有的飞机高度表都使用同一个参考面，大家的误差都一样，因此飞机之间仍可以保持所规定的安全距离。
　　
3、密度高度：将压力高度值对温度校验后的高度。如果大气温度符合国际标准大气的状况，密度高度等于压力高度。密度高度最主要的目的是让飞行员以及飞机设计制造公司计算及了解正确的飞机性能值，并不是来作为高度的参考。
　　
4、绝对高度：通常是指经由无线电波/雷达高度表所显示出来的高度，基准为地面，但没有压力高度表的压力调拨值问题。英文中常用地面以上的缩写AGL来表示。飞机在通过或降落高山地区的空域时，使用绝对高度作为参考就比使用指示高度或压力高度来得安全。
　　
在美国联邦航空法规第91.121章节的内容中，针对一般飞机在飞行时设定压力调拨值的规定为：在平均海平面18,000英尺高度以下时，以当时飞行途径上100海浬之内的航管中心为准；在平均海平面18,000英尺高度以上时，一律设在29.92英寸汞柱。
　　
由于高度表有相当的重要性，因此在美国联邦航空法规第43章「航空器的维修」附录E的内容中，特别规定了高度表的测试与检修有关事项。而在第91.411章节里则规定，若飞机的高度表没有依照第43章附录E的测试检修规定执行的话，这架飞机是不允许飞行的；同时亦规定谁有资格来执行高度表测试与检修，由于条文较多，不在此赘述。
　　
结语
　　
由于压力高度表所量测出来的高度并不是一个真实的高度值，因此当我们在谈论飞机的飞行高度时，并不是我们想象中那样简要，除了要了解高度表的原理和其限制外，同时要清楚各种高度的定义以及航管规定，才会有一个安全的飞行间隔距离。

下次你在搭乘飞机听到飞行员广播飞机的飞行高度时，想必会发出会心一笑，飞行高度原来是这个意思！

The Basic of Flight ( 4 )

2009-04-06T23:03:00.005+08:00

4. BASIC FLIGHT MANEUVERS

This section covers the basics of flight—takeoff, climbing, descending and landing—and outlines basic recovery procedures for stalls, a common occurrence.

TAKEOFF
Taking off from an airfield is a fairly straightforward procedure. First, lower the flaps to change the aerodynamic shape of the wing, and then apply full throttle.

Once you generate enough forward airspeed and lift, the tailwheel (if the aircraft has one) rises off of the runway surface. Gently apply rear stick to pitch the nose up approximately 10°. Be careful not to climb too steeply— if your airspeed starts falling, you'll need to reduce the pitch angle to avoid stalling.

..Lower flaps
..Increase throttle to 100%
..Wait until your speed is over 160 km/h. (Exact airspeeds for takeoff vary by airplane).

Gently apply pitch (pull back on flight stick) so that your climb attitude is around 5°
..Keep pitch steady (if airspeed drops, reduce pitch)

CLIMBING
After you take off, the next step is to retract the landing gear—it creates unnecessary drag, and once you're airborne it's important that you reduce drag in order to build up speed.
Keep your throttle on its full setting, and pitch the nose slightly upward until it's at about a 20° angle. If you start to lose airspeed or if the STALL warning appears onscreen, dip the nose down until you're again flying level. Then, resume climbing at a gentler angle.

As long as no approaching aircraft are in your flight path, you can maintain this climbing position until you reach the desired altitude. You can also angle gently toward your first waypoint, although turning will sacrifice some airspeed and lift.

Once you decide you're ready to level out, reduce the throttle until you slow down to the desired cruising speed (flying on full throttle quickly consumes fuel, and you might not have enough to make the return trip home). Make slight adjustments to the throttle setting until you're flying at a constant speed and altitude.

..Retract landing gear
..Maintain full throttle
..Pitch upward at a 20-degree angle
..Level out
..Reduce throttle to desired airspeed
..Make slight throttle adjustments until you have a constant speed and altitude

DESCENDING / DIVING
There are two methods by which you can reduce your altitude. First, you can reduce your throttle setting, which creates less lift and therefore drops your altitude. If you aren't particularly concerned with getting down in a hurry, this method is fine. You maintain level flight without losing noticeable airspeed (although you reduce the throttle, your aircraft gains some speed while descending due to gravity).

The second method is to redirect the nose by pitching down. This is the more drastic method—you bleed off altitude in a hurry and gain airspeed. The dive is often used to attack a lower-flying aircraft or as a recovery procedure following a stall.

Be wary of prolonged dives or extremely steep dives at low altitude—your aircraft's controls may "freeze" due to compressibility (air moves so quickly over the control surfaces that they're rendered useless).

..Decrease throttle to slowly lose altitude at the current airspeed
..Alternatively, pitch down to descend quickly and gain airspeed

BANKED TURNS
Turning is also know as banking, or combining pitch and roll maneuvers to alter your heading. By pulling the stick back and either left or right, you make a banked turn. You can also apply rudder in the intended direction of the turn to make the turn more quickly.

If you enter a banked turn without adjusting the throttle, you lose altitude, airspeed, or both by the time you finish turning. This occurs for two reasons. First, you change the angle of attack (angle of the wings as they meet the airflow).

This creates drag that slows down the aircraft. Secondly, lift acts nearly perpendicular to your aircraft's wings. If the wings are angled, so is the lift vector. You have less pure vertical force, so you drop in altitude.

If you want to maintain altitude and speed, apply extra throttle before you start banking.

..Push stick left or right to bank the airplane.
..Pull back on the stick to begin the turn.

LANDING
Landing sounds simple—you reorient your aircraft's nose so that it's pointing in the general direction of the airfield, bleed off some speed and altitude, lower the gear, and touch down. But in reality, many factors affect whether you land an aircraft safely or convert it into a junk pile.

Landing takes a steady hand and a smooth series of changes in throttle and pitch. When you're ready to land, you need a range of at least 5 km from the airfield. Make sure you are flying level at about 150 meters of altitude and that your throttle is set to about three-quarter speed. Drop the gear and lower the flaps—with flaps, you have more lift and can slow down without going into a stall. Gently pitch down to start your descent, striving for a maximum airspeed of about 190 km/h.

Once the aircraft reaches the edge of the runway, you should have between 6 to 9 meters of altitude. Pull the stick back firmly to raise the nose up past the horizon and chop the throttle to zero. The main wheels will touch down. As your skills progress, you may even touch down all of the aircraft's tires simultaneously.

..Line up with the runway 5 km out
..Fly level at 150 meters of altitude
..Reduce speed until you're below 190 km/h
..Lower the landing flaps
..Lower the landing gear
..Gently pitch down
..Reduce airspeed even further
..At the edge of the runway, with 6 to 9 meters of altitude, pitch the nose up 15°
..Cut the throttle to zero

STALLS
A stall is the loss of lift. They occur because your aircraft's speed has dropped below the airspeed required to maintain lift. Without lift, your aircraft falls toward the ground and your control surfaces are useless, much like a sail without a breeze to propel it.

Stalls are most commonly experienced during tight turns, steep climbs, loops, or takeoffs and landings. To solve a stall situation, let the aircraft fall and try to keep the nose oriented toward the ground (most aircraft nose down automatically). Make sure the throttle is set at 100%. Eventually, this buys enough airspeed to restore airflow over the control surfaces and let you regain control of your aircraft.

Let the aircraft fall to regain airspeed, then slowly level out when controls respond
Increase throttle to 100% if it is currently lower
Alternatively, increase throttle to regain airspeed

SPINS
A spin is a special type of stall that happens when one wing loses lift, but the other does not. More often than not, a spin occurs when you make a hard turn and have the nose pitched too steeply. Lift fails on one wing, and it begins to drop toward the ground. Meanwhile, the opposing wing keeps producing lift and rising. If the rudder is engaged, it rotates the aircraft about its yaw axis. The result is a spinning corkscrew motion.

All aircraft have a critical angle of attack, or a maximum angle at which the wings can still provide lift. If you nose up drastically at high speeds, you may surpass this angle and initiate a stall or spin.

To recover from a spin, you have to neutralize the aircraft's rotating motion. The best way to accomplish this is to center the stick and apply rudder in the opposite direction of the spin. Then, nose the plane downward. Hopefully, you'll have enough altitude to recover and break out of the spin.

..Restore stick to center position
..Apply rudder opposite the spin (if you're spinning left, apply right rudder)
..Pitch down
..When you stop spinning, level out

The Basic of Flight ( 3 )

2009-04-06T23:03:00.004+08:00

3. CONTROL SURFACES

All control surfaces utilize the principle of lift, but they apply lift forces in different directions.

These forces act either independently or in conjunction with one another to producevarious maneuvers. Each maneuver is the net resultant force of all individual forces. (A resultant force is the average force that results when two forces are combined. For example, a pure vertical force and a pure horizontal force create an angled force.)

ELEVATORS
Elevators are flat, hinged surfaces on the tailplane (the horizontal part of the tail assembly). While the entire tailplane surface helps stabilize the aircraft during flight, the elevators apply pitch by angling the trailing (rear) edge of the tailplane up or down.

To create pitch, gently pull the flight stick back or push it forward. Take care not to perform pitch maneuvers too quickly. If the angle of attack (angle that the air meets the wing) becomes too steep, the flow of air around the wings can become disrupted. Air no longer flows smoothly over the wing; instead, it buffets in several different directions and disrupts the air pressure around the wing's surface. This situation is called a stall.

Stalls can also occur from lack of airspeed, when not enough air flows over the wings to create lift. This is commonly encountered in propeller-powered aircraft, especially during steep climbs in which gravity reduces airspeed. Note that climbing steeply is not the same thing as pitching up too quickly. The former type of stall is caused by lack of airspeed, while the second type is due to disrupted airflow around the wing.

RUDDERS
The rudder is the vertical component of the tail assembly. The rear half of the vertical tail section is hinged, allowing it to angle left or right. When you apply rudder, you redirect the aircraft's nose either left or right. Applying left rudder yaws the nose to the left, while applying right rudder veers the nose to the right. Note that applying rudder also produces a very slight rolling movement, which can be negated by pushing the stick in the opposite direction.

AILERONS
Ailerons are thin, hinged surfaces on the outer, trailing edge of each wing. They angle in opposite directions to waggle the wings up and down or roll the aircraft about its nose-tail axis. If you apply stick left or right, one wing's aileron angles down and the other angles up. This rolls one wing up and forces the other wing down, effectively rolling the airplane.
When you apply left stick, the left aileron raises and the right one drops, and the aircraft rolls to the left. The opposite occurs if you push the stick in the opposite direction.

FLAPS
Similar to ailerons, flaps are thin, hinged surfaces on the trailing edge of the wing. However, they are located nearer to the wing root than ailerons and operate in tandem. (If one flap is lowered or raised, so is the other.) A raised flap conforms to the wing's natural shape. A lowered flap alters the airflow around the wing, effectively changing the wing's aerodynamic shape and increasing the amount of available lift.

You extend flaps during takeoff to gain additional lift, then retract them during flight to maximize your airspeed. While flaps increase your aircraft's angle of attack, they also increase drag. In a pinch, you can use flaps while chopping the throttle to quickly reduce your airspeed.
One point to note is that flaps can only be extended at low to medium speeds. If the aircraft is traveling too fast, air flows too fast over the flaps, and they cause drag. In high-speed dives, flaps and other control surfaces may become unusable—air travels so fast over them that you can't move them until you slow down the aircraft.

COMPRESSIBILITY
Compressibility is a condition that renders an aircraft's control surfaces inoperable. It occurs at very high speeds, such as those attained during a long, steep dive. Air that flows around the airfoil surface separates into two directions at some point in front of each wing. This is called the point of impact.

At higher speeds, this point moves further and further in front of the wing and creates pressure disturbances on and around the wing. As an aircraft's speed approaches Mach 1, the speed of the air flowing over the wings reaches the speed of sound before the aircraft does. Remember, air flows faster over the top of the wing and is actually traveling faster than the aircraft at any given point in time.

Pressure waves generated by the movement of wings through the air act much like ripples on a pond. They radiate outward and “warn” the yet undisturbed air molecules in the path of the approaching wing. As the aircraft's speed approaches Mach 1, these pressure waves pile up in front of the wing. (The Mach number is the aircraft's speed divided by the speed of sound for the current altitude and temperature.)

At some point, the wing is traveling so fast that the waves no longer radiate ahead of the wing. This creates shock waves and causes the aircraft to buffet. Aileron and elevator controls mounted on the wing and tail surfaces freeze up due to excessive pressure, or act in directions opposite than normal. The phenomenon of compressibility occurs only at very high speeds. The only remedy in WW II aircraft is to chop the throttle and attempt to pull out before it's too late. If you don't react quickly enough, your control surfaces may freeze and you could crash.

The Basic of Flight ( 2 )

2009-04-06T22:57:00.006+08:00

2. MOVEMENT VECTORS

Pitch is the up and down movement of the aircraft's nose around an axis line drawn from wingtip to wingtip. When you apply pitch by pulling back on the stick, you angle the aircraft's elevators up, causing the nose to rise.

Yaw is the side-to-side rotation of the aircraft's nose around a vertical axis through the center of the aircraft. It changes the direction of horizontal flight, but does not affect altitude. You use the rudder to angle the aircraft's rudder left or right, which creates yaw.

Roll is the tipping of the wings up or down. The aircraft maintains its current direction of flight, but the wings spin around an imaginary line drawn from the nose through the tail. Roll occurs when you push the stick left or right, causing one aileron to angle down and the other to angle up. This increases lift under one wingtip while decreasing lift under the other, creating roll.

BANK
You can combine pitch and roll movements to make a banking turn. By pitching the nose up and applying right stick, you cause the aircraft to bank to the right. You can accomplish a left bank by pitching up and applying left stick. A banking turn changes both the angle of the nose and the direction of flight.

One side-effect of a banked turn is that you lose both lift and airspeed. If you want to preserve your altitude and energy, it's always a good idea to apply a bit of extra throttle preceding a bank turn.

The Basic of Flight ( 1 )

2009-04-06T22:33:00.010+08:00

1. PHYSICS

The miracle of flight exists because man has the technology to oppose natural forces that keep all objects on the ground. Four forces affect an aircraft — two assist flight (thrust and lift), and two resist flight (gravity and drag). The important thing to note here is that when an aircraft is flying straight and level, all four of these forces are balanced, or in equilibrium.

THRUST

Thrust is created by the engines. As propeller blades push air through the engine (or as jet fuel is combusted to accomplish the same end), the aircraft moves forward. As the wings cut through the air in front of the aircraft, lift is created. This is the force that pushes an aircraft up into the air.

LIFT

Lift occurs because air flows both over and under the surface of the wing. The wing is designed so that the top surface is "longer" than the bottom surface in any given crosssection. In other words, the distance between points A to B is greater along the top of the wing than under it. The air moving over the wing must travel from A to B in the same amount of time. Therefore, the air is moving faster along the top of the wing.

This creates a difference in air pressure above and below—a phenomenon called the Bernoulli effect. The pressure pushing up is greater than the downward pressure, and lift is created. If you're banking, lift occurs in a slightly sideways direction. If you're inverted, lift actually pulls you downward toward the ground. Note that lift occurs perpendicular to a line drawn parallel to the centerline of the wing and occurs at a slightly backward angle.

Several factors determine how much lift is created. First, consider the angle at which the wing hits the air. This is called the angle of attack, which is independent of the aircraft's flight path vector. The steeper this angle, the more lift occurs. At angles steeper than 30° or so, however, airflow is disrupted, and an aircraft stall occurs. During a stall, no lift is created. The aircraft falls into a dive and can recover lift only after gaining airspeed.

DRAG

Drag opposes thrust. Although it mainly occurs because of air resistance as air flows around the wing, several different types of drag exist. Drag is mainly created by simple skin friction as air molecules "stick" to the wing's surface. Smoother surfaces incur less drag, while bulky structures create additional drag.

Some drag has nothing to do with air resistance and is actually a secondary result of lift. Because lift angles backward slightly, it is has both an upward, vertical force and a horizontal, rearward force. The rearward component is drag. Another type of drag is induced at speeds near Mach 1, when a pressure differential starts building up between the front and rear surface of the airfoil. The pressure in front of the wing is greater than the pressure behind the wing, which creates a net force that opposes thrust. In WW II aircraft, this last type of drag occurred only during prolonged dives.

GRAVITY

Gravity is actually a force of acceleration on an object. The Earth exerts this natural force on all objects. Being a constant force, it always acts in the same direction: downward. Thrust creates lift to counteract gravity. In order for an aircraft to take off, enough lift must be created to overcome the force of gravity pushing down on the aircraft.
Related to gravity are G-forces—artificially created forces that are measured in units equivalent to the force of gravity.

G-Force

A "G" is a measurement of force that is equal to the force of gravity pushing down on a stationary object on the earth's surface. Gravitational force actually refers to an object's weight (Force equals Mass times Acceleration, or F = ma.). An aircraft flying level at low altitudes experiences 1G. Extra G-forces in any direction can be artificially created by sudden changes in velocity or in the direction of motion. Good examples are a takeoff, a tight turn in an aircraft at moderate to high speed or a loop maneuver.

G-forces can be either positive or negative. Positive Gs make you feel heavier because they act in a relative downward direction. They push you back into your seat and primarily occur during sharp turns or steep climbs. Negative Gs make you feel lighter because they're pulling in a relative upward direction. When you're in a steep dive, they pull you out of your seat. The direction of G-forces is always relative to the position of the aircraft—if you're flying upside-down, upward Gs actually pull in a downward direction.

Apparent Weight

Apparent weight refers to how heavy something seems considering the current direction and magnitude of G-forces acting on it. In level flight, 1G is acting on the aircraft and the pilot—both weigh the same as they do when stationary. If the pilot makes a steep climb, the positive G-force temporarily acts on both the pilot and the aircraft, making them in essence heavier throughout the climb. Any sudden increase or decrease in acceleration brings about a change in apparent weight of an object.

Physical Effects of G-Forces

Human bodies can withstand approximately 9 or 10 positive Gs or 2 to 3 three negative Gs for several seconds at a time. Exceeding positive G limits for longer than that causes blood to collect in the lower part of the body and torso. The brain and retinas receive less blood, and therefore less oxygen. Eventually, vision turns gray, followed by tunnel vision and pilot blackout. Excessive negative Gs have a similar effect, except that blood pools in the brain and upper torso. This causes the small capillaries in the eyes to swell, creating a redout effect.

The Aviation Dictionary

2009-04-06T22:21:00.003+08:00

ABSOLUTE CEILING - The maximum altitude above sea level at which a heavier-than-air craft can be maintained in level flight.

ACLS - (I) Air cushion landing system, or (II) automatic carrier landing system.

ADF - Automatic Direction Finding; utilizing an automated radio direction finding (RDF) technique.

AEROBATICS - Voluntary maneuvers, initiated by a pilot, other than those for conventional flight.

AERODROME - An area set aside for the operation of aircraft.

AERODYNAMICS - The branch of fluid mechanics dealing with air (gaseous) motion, and the reactions of a body moving within that air.

AEROFOIL (AIRFOIL) - A body or structure shaped to obtain an aerodynamic reaction when travelling through the air.

AERONAUTICS - Concerned with flight within the Earth's atmosphere.

AEROPLANE (AIRPLANE)- Meaning in modern usage a heavier-than-air powered craft.

AEROSTAT - A lighter-than-air craft.

AEW - Airborne early warning; aircraft equipped to give maximum advance warning of approaching hostile aircraft.

AFCS - Automatic flight control system.

AFTERBURNER - Thrust augmentation feature of a gas turbine engine.

Al- Airborne interception; radar device carried by military aircraft to aid location and interception of hostile aircraft.

AILERONS - Movable control surfaces, usually mounted in the trailing-edge of a wing adjacent to the wingtips, to control an aircraft's rolling movements.

AIRBRAKE- A drag-inducing surface which can be deployed in flight, perhaps for speed reducing or limiting, but see also spoilers.

AIRFIELD- More modern term for aerodrome, and applying more particularly to one used by military aircraft.

AIRFLOW- The movement of air about a body (aircraft) in motion.

AIRFOIL (AEROFOIL)- A structure shaped to obtain an aerodynamic reaction in the air, thus affecting the performance of the aircraft.

AIRFRAME - An aircraft's structure, without power plant and systems.

AIRPLANE (AEROPLANE) - Meaning in modern usage a heavier-than-air powered craft, as opposed to a balloon or glider.

AIRPORT - More modern term for aerodrome, and applying more particularly to one used for civil transport operations.

AIRSCREW - Now little-used word for propeller; believed to have originated to provide distinction from ship's propeller.

AIRSHIP - A powered lighter-than-air craft.

AIRSPEED - The speed of an aircraft through the air, relative to the air mass in which it is moving.

AIRSTRIP - A natural surface used for the operation of aircraft, often in an unimproved state.

ALTIMETER - An instrument, most usually an aneroid barometer, calibrated in meters and/or feet, to indicate an aircraft's height.

ALTITUDE - Height

AMPHIBIAN - An aircraft able to operate from both land and water.

ANGLE OF ATTACK - Angle at which the air-stream meets an aerofoil surface.

ANGLE OF INCIDENCE - Angle at which an airfoil surface is normally set in relation to the fore and aft axis of the airframe structure.

ANHEDRAL - Angle which the spanwise axis of an airfoil makes to the fuselage when the wing or tailplane tip is lower than its root attachment point.

APU - Auxiliary power unit. Usually small engine carried on board an aircraft to provide an independent power source for such services as electrics, hydraulics, pneumatics, ventilation, and air conditioning, both on the ground and in the air if needed.

ASI - Air speed indicator.

ASPECT RATIO - Ratio of the span to the chord of an airfoil. Hence, a high aspect ratio wing has great span and narrow chord, and vice versa.

ASTRODOME - Transparent dome, usually on dorsal surface of fuselage, to permit celestial navigation by traditional means.

ASW - Antsubmarine warfare.

ATC - Air traffic control.

AUTOGYRO - An aircraft with an unpowered rotary wing, which autorotates as the machine is propelled through the air by a conventional power plant. "Autogiro" is the trade name for autogyros developed by Juan de la Cierva.

AUTOMATIC PILOT (AUTOPILOT) - A gyroscopically stabilized system maintaining an aircraft in level flight at predetermined heading and altitude.

AUTOROTATION - Automatic rotation of a rotary wing due to forward, or downward, movement of an autogyro

AWACS - Airborne warning and control system; an advanced AEW aircraft, with additional facilities for deployment and control of defence, interception, and counter-strike forces.

BALLISTIC MISSILE - A weapon which, in the terminal and unpowered stage of its flight, becomes a free-falling body subject to ballistic reactions.

BALLOON - An unpowered lighter-than-air craft, its direction of flight imposed by ambient airstreams.

BIPLANE - A fixed-wing aircraft with two sets of wings mounted, generally, one above the other.

BLEED AIR - Hot air, at high pressure, taken usually from the bypass section of a gas turbine engine, for heating, de-icing and other useful work.

BLOWN FLAPS - Aerodynamic surface over which bleed air is discharged at high speed to prevent breakaway of the normal airflow.

BOUNDARY LAYER - Thin stratum of air nearest to an aircraft's external surface structure.

BOX KITE - Form of kite devised by Australian Lawrence Hargrave, used by many early constructors to provide rigid biplane structures.

BUFFET - Irregular, often violent, oscillations of an aircraft's structure, caused by turbulent airflow or conditions of compressibility.

CAA - Civil Aviation Administration (U.K.).

CAB - Civil Aeronautics Board (U.S.A.).

CABIN - Enclosed compartment for crew and/or passengers in an aircraft.

CAMBER - The curvature, convex or concave, of an airfoil surface.

CANARD - Describes an aircraft which flies tail first, with its main lift surface at the aft end of its structure.

CANTILEVER - A beam, or other structure, supported at one end only, and without external bracing.

CATHEDRAL - Early word to describe anhedral, or negative dihedral.

CEILING - Normal maximum operating altitude of an aircraft.

CENTER OF GRAVITY - (CQ), the point on an aircraft's structure where the total combined weight forces act.

CENTER-SECTION - The central panel, or section, of an aircraft's wing.

CHORD - The distance measured from the leading-to trailing-edge of an airfoil.

COCKPIT - Compartment, originally open to the air, for accommodation of pilot'and crew/passengers. Nowadays used informally by laymen to describe the forward part of the cabin, especially of an airliner, which is off-limits to passengers, and properlv called flight deck.

COIN - Counter-insurgency aircraft.

COLLECTIVE PITCH CONTROL - Used to change simultaneously the pitch of all of a helicopter rotor's blades to permit ascent or descent.

CONSTANT-SPEED PROPELLER - One which governs an engine at its optimum speed, the blade pitch being increased or decreased automatically to achieve this result.

COWLING - The name of the fairing which, usually, encloses an engine.

CYCLIC PITCH CONTROL - Means of changing the pitch of a rotor's blades progressively, to provide a horizontal thrust component for flight in any horizontal direction.

DELTA WING - When viewed in plan has the shape of an isosceles triangle; the apex leads, the wing trailing-edge forming the base of the triangle.

DERATED - An engine which is restricted to a cower output below its potential maximum.

DIHEDRAL - Angle which the spanwise axis of an aerofoil makes to the fuselage when the wing or tailplane tip is higher than its root attachment point (positive dihedral).

DIVE BRAKE - Drag-inducing surface deployed in a dive to maintain speed below structural limitations, or improve controllability (see airbrake).

DORSAL - Relating to the upper surface of an aircraft's fuselage.

DRAG - A force exerted on a moving body in a direction opposite to its direction of motion.

DRAG CHUTE - A heavy-duty parachute attached to an aircraft's structure which can be used to reduce its landing run.

DRONE - A pilotless aircraft, usually following a predetermined or programmed set of maneuvers. See also RPV.

DROP TANK - An externally carried auxiliary tank, usually to contain fuel, which may be jettisoned if necessary.

ECM - Electronic counter-measures; airborne equipment to reduce the effectiveness of an enemy's radar or other devices which generate electromagnetic radiations.

ELEVATOR - Movable control surface, attached to the trailing-edge of an aircraft's tailplane (stabilizer) to controll pitching movements.

ELEVONS - Movable control surfaces which act collectively as elevators, but differentially as ailerons.

ELT - Emergency locator transmitter; emits a homing signal from a crashed aircraft to simplify location for rescue services.

ENVELOPE - Container, usually flexible, or the lifting gas or hot air of an airship or balloon.

FAA - Federal Aviation Administration.

FAI - Federation Aeronautique Internationale.

FAR - Federal Aviation Regulations.

FIN - A fixed vertical aerofoil surface, usually a dorsal component of the tail unit, to provide stability in yaw.

FIRING - An addition to an aircraft's basic structure which is intended primarily to reduce drag.

FLAP - Most usually awing trailing-edge movable surface which can be deployed partially to increase lift, or completely to increase drag.

FLAT-FOUR - Characteristic description of a horizontally opposed four-cylinder engine; hence flat-twin, flat-six.

FLIGHT DECK - (I) Separate crew compartment of a cabin aircraft, or (II) the operational deck of an aircraft carrier.

FLIGHT SIMULATOR - A ground-based training device to permit the practice of flight operations; often specific to a particular aircraft for detailed training.

FLOATPLANE - Aircraft which is supported on the water by floats; more usually termed a seaplane

FLUTTER - Unstable oscillation of an airfoil surface.

FLYING-BOAT - A heavier-than-air craft which is supported on the water by its water-tight fuselage.

FLYING WIRES (LIFT WIRES) - External bracing wires, usually of streamline section, which carry the weight of the fuselage in flight.

FULLY-FEATHERING PROPELLER - One in which the blades can be rotated so that the leading-edge of each faces the oncoming airstream. This reduces drag if an engine has to be stopped in flight.

FUSELAGE - The body structure of an aircraft.

GLIDER - A heavier-than-air, fixed wing, unpowered aircraft for gliding or soaring flight.

HARDPOINT - A strengthened section of the under-wing or fuselage, intended for the carriage of external weapons or stores, usually on pylons.

HELICOPTER - A heavier-than-air craft with a powered rotary wing.

HELIUM - A non-inflammable lifting gas tor lighter-than-air craft.

HIGH-WING MONOPLANE - An aircraft which has its single wing mounted high on the fuselage.

HULL - The water-tight fuselage or body of a flying-boat.

HYDRO-AEROPLANE - Early term for an aircraft which could operate from water.

HYDROGEN - The lightest known lifting gas, used to inflate balloons and airships, unfortunately highly inflammable.

IATA - International Air Transport Association.

ICAO - International Civil Aviation Organization.

ICING - Condition arising when atmospheric moisture freezes on the external surfaces of an aircraft.

IFF - Identification, friend or foe; an electronic device to interrogate approaching aircraft.

IFR - Instrument Flight Rules; i.e. flight by reference to on-board instruments under conditions of poor visibility or darkness.

ILS - Instrument Landing System.

IN-LINE ENGINE - Engine in which the cylinders are one behind another, in straight lines.

INS - Inertial navigation system, in which highly sensitive accelerometers record, via a computer, the complex accelerations of an aircraft about its three axes, thus integrating its linear displacement from the beginning of a selected course and pinpointing the aircraft's position at all times.

ISA - Agreed International Standard Atmosphere (1013.2 millibars at 15'C) to permit accurate comparison of aircraft performance figures.

JATO - Jet-assisted take-off, utilising solid or liquid fuel rockets to augment the take-off power of an aircraft's engines. See also RATO.

KINETIC HEATING - Heating of an aircraft's structure as a result of air friction.

KITE - Usually tethered heavier-than-air craft, sustained in the air by its airfoil surfaces being inclined to the wind to generate lift.

LANDING WEIGHT - Normal maximum weight at which an aircraft is permitted to land.

LANDING WIRES - External bracing wires, usually of streamline section, which support the wings when the aircraft is on the ground.

LANDPLANE - A heavier-than-air craft which is equipped to operate from land surfaces only.

LBA - Luftfahrtbundesamt; the Federal German Civil Aviation Authority.

LEADING-EDGE - The edge of an airfoil which first meets the airstream in normal flight.

LIFT - The force generated by an airfoil section, acting at right angles to the airstream flowing past it

LORAN - A long-range radio-based navigation aid.

LOW-WING MONOPLANE - An aircraft which has its single wing mounted low on the fuselage.

MACH NUMBER - Named after the Austrian physicist Ernst Mach, a means of recording the speed of a body as a ratio of the speed of sound in the same ambient conditions. The speed of sound in dry air at 32"F (CTC) is approximately 1087ft/sec (331m/sec); 741mph (1193km/h). Hence Mach 0.8 represents eight-tenths of the speed of sound.

MAD - Magnetic anomaly detector carried, for example, by maritime reconnaissance aircraft to locate a submarine beneath the surface of the sea.

MID-WING MONOPLANE - An aircraft which has its single wing mounted in a mid-position on the fuselage.

MONOCOQUE - Structure in which the outer skin carries the primary stresses, and is free of internal bracing.

MONOPLANE - A fixed-wing aircraft with a single set of wings, i.e. one wing on each side.

NACA - National Advisory Committee for Aeronautics. Now NASA.

NAF - Naval Aircraft Factory (U.S.).

NASA - National Aeronautics and Space Administration.

NATO - North Atlantic Treaty Organization.

ORNITHOPTER - Name for a flapping-wing aircraft. Only model ornithopters have flown to date.

PARACHUTE - Collapsible device which, when deployed, will retard the rate of descent of a body falling through the air. Used originally as a safety device, has been adopted for dropping troops, supplies, equipment, etc.

PARASOL MONOPLANE - A fixed-wing aircraft which has its single wing strut-mounted above the fuselage.

PAYLOAD - The useful load of an aircraft cargo, passengers; in a military aircraft, its weapon load.

PITCH - The angle of incidence at which a propeller blade or rotor blade is set.

PORT - Left-hand side when facing forward.

PRESSURIZATION - Artificially increased pressure in an aircraft to compensate for the reduced external pressure as the aircraft gains altitude.

PROPELLER - Rotating blades of aerofoil section, engine driven, each of which reacts as an aircraft's wing, generating low-pressure in front and higher behind, thus pulling the aircraft forward.

PROTOTYPE - The first airworthy example of a new aircraft design or variant.

PUSHER PROPELLER - Inaccurate but accepted description of propeller mounted behind an engine. It acts aerodynamically as described under propeller, and is thus a tractor in action.

PYLON - Structure attached to wing or airframe to carry load, e.g. engines or weapons.

RADAR - Beamed and directed radio waves used for location and detection, as well as for navigational purposes.

RADIAL ENGINE - One in which the cylinders are mounted equidistant and circumferentially around a circular crankcase. Cylinders and crankcase are fixed, and the crankshaft rotates.

RAE - Royal Aircraft Establishment, formerly Royal Aircraft Factory.

RAF - Royal Aircraft Factory.

RAI - Registro Aeronautico Italiano.

RAMJET ENGINE - An aerodynamic duct in which fuel is burned to produce a high-velocity propulsive jet. It needs to be accelerated to high speed before it can become operative.

RATO - Rocket-assisted take-off virtually the same as JATO.

RDF - Radio direction finding; using the transmission from two or more stations to fix position of an aircraft by its bearing in relation to each.

ROCKET ENGINE - One burning liquid or solid fuel and carrying Its own oxidizer, enabling combustion to continue outside of the earth's atmosphere.

ROLL - Movement of an aircraft about its longitudinal axis, representing a wing-over rolling action.

ROTARY ENGINE - Cylinders disposed as for radial engine, but in this case the crankshaft is fixed, and cylinders and crankcase rotate around it.

ROTOR - The rotating-wing assembly of an autogyro or helicopter, comprising the rotor hub and rotor blades.

RPV - Remotely piloted vehicles, directed usually by radio by a pilot in another aircraft or based on the ground.

RUDDER - Movable control surface, attached to trailing-edge of fin, to control aircraft movement in yaw.

SAILPLANE - An unpowered heavier-than-air craft designed primarily for soaring flight.

SEAPLANE - A heavier-than-air craft which operates from water, and is supported on the surface of the water by floats.

SEMI-MONOCOQUE - An aircraft structure in which the outer skin is inadequate to carry the primary stresses, and is reinforced by frames, formers and longerons.

SERVICE CEILING - Normally height at which an aircraft can maintain a maximum rate of climb of 100 ft (30 m) /min.

SGAC - Secretariat Generate A I'Aviation Civile.

SKIN - The external covering of an aircraft's basic inner structure.

SLAT - Auxiliary airfoil surface, mounted forward of a main airfoil, to maintain a smooth airflow over the main airfoil at high angles of attack.

SLOT - The gap between the slat and leading-edge of the main airfoil, which splits the airflow and maintains a smooth flow over the main airfoil upper surface.

SPAN - The distance from tip to tip of the wing or tailplane.

SPAR - A primary structural member of an airfoil surface, from which ribs or frames are mounted to form the desired airfoil contours.

SPINNER - A streamlined fairing over a propeller hub.

SPOILERS - Drag-inducing surfaces which can be deployed differentially for lateral control, or simultaneously for lift dumping to improve the effectiveness of landing brakes.

STALL - Condition which arises when the smooth airflow over a wing's upper surface breaks down and its lift is destroyed.

STARBOARD - Right-hand side when facing forward.

STOL - Short take-off and landing capability.

STREAMLINE - To shape a structure so that it will cause the minimum aerodynamic drag.

STRUT- Solid or tubular member, usually streamlined, used for bracing, as, for example, between the two wings of a biplane. Can be required to carry tension or compression loads.

SUBSONIC - Flight at a speed below that of sound.

SUPERCHARGER - A form of compressor, often turbine-driven, to force more fuel/air mixture into the cylinders of a piston-engine than can be induced by the pistons at ambient atmospheric pressure.

SUPERSONIC - Speed in excess of that of sound.

SV-VS - Soviet Military Aviation Forces (Sovietskiye Voenno-Vozdushnye Sily).

SWEPT WING - Wing of which the angle between the wing leading-edge and the centre line of the rear fuselage is less than 90 degrees.

TABS - Small auxiliary control surfaces which can be adjusted to offset aerodynamic loads imposed on main control surfaces.

TAILPLANE (STABILIZER) - Primary horizontal airfoil surface of tail unit. Can be fixed, or may have variable incidence, and its purpose is to provide longitudinal stability.

TAKE-OFF WEIGHT - Maximum allowable weight of an aircraft at the beginning of its take-off run.

THRUST - Force which propels an aircraft through the air; generated by conventional propeller or the jet efflux of a turbine engine.

TRACTOR PROPELLER - Propeller mounted forward of the engine. (See propeller.)

TRAILING-EDGE - The rear edge of an aerofoil.

TRIPLANE - Fixed-wing aircraft with three sets of wings, mounted one above another.

TURBOFAN - Gas turbine engine with large diameter forward fan. Air is dueled from the tips of these fan blades and by-passed around the engine, and added to the normal jet efflux to provide high propulsive efficiency.

TURBOJET - Gas turbine engine in its simplest form, producing a high velocity jet efflux.

TURBOPROP - Gas turbine engine in which maximum energy is taken from the turbine to drive a reduction gear and conventional propeller.

TURBOSHAFT - Gas turbine engine in which maximum energy is taken from the turbine to drive a high speed shaft. It can be used to drive a helicopter's rotor or any other form of machinery.

VARIABLE-GEOMETRY WING - Wings which, fully extended, give the best low-speed performance for take-off and landing, and can be swept in flight to optimum positions for best cruising and high-speed flight performance.

VARIABLE-PITCH PROPELLER - Usually a propeller in which the blades can be set to two positions a fine-pitch setting for take-off and landing, and a coarse-pitch setting for economic cruise performance.

VEE-ENGINE - One with two banks of in-line cylinders mounted with an angular separation on a common crankcase.

VENTRAL - Relating to the under-surface of an aircraft's fuselage.

VFR - Visual Flight Rules; i.e. flight under conditions of good external visibility, without dependence on aircraft instruments.

VSTOL - Vertical or short take-off and landing.

V/STOL - Vertical and/or short take-off and landing capability.

VTOL - Vertical take-off and landing capability.

WING-LOADING - The gross take-off weight of an aircraft divided by its wing area. A Boeing 747, for example, can have a maximum wing loading of 149Ib/sq ft (727.8kg/m2); a high-performance sailplane, such as the Scheibe Bergfaike, can be as low as 6.02Ib/sq ft (29.4kg/m2).

WING WARPING - Method of lateral control adopted by Wright brothers and many early builders/designers, in which a flexible wing is twisted (warped) to provide roll control as with ailerons.

YAW - Movement of an aircraft about its vertical axis, representing movement of its tail unit to port or starboard, to change the aircraft's heading.

飞行原理简介（二）

2009-04-06T22:16:00.001+08:00

要了解飞机的飞行原理就必须先知道飞机的组成以及功用，飞机的升力是如何产生的等问题。这些问题将分成几个部分简要讲解。

一、飞行的主要组成部分及功用
　　
到目前为止，除了少数特殊形式的飞机外，大多数飞机都由机翼、机身、尾翼、起落装置和动力装置五个主要部分组成　　

1. 机翼--机翼的主要功用是产生升力，以支持飞机在空中飞行，同时也起到一定的稳定和操作作用。在机翼上一般安装有副翼和襟翼，操纵副翼可使飞机滚转，放下襟翼可使升力增大。机翼上还可安装发动机、起落架和油箱等。不同用途的飞机其机翼形状、大小也各有不同。　　

2. 机身--机身的主要功用是装载乘员、旅客、武器、货物和各种设备，将飞机的其他部件如：机翼、尾翼及发动机等连接成一个整体。　　

3. 尾翼--尾翼包括水平尾翼和垂直尾翼。水平尾翼由固定的水平安定面和可动的升降舵组成，有的高速飞机将水平安定面和升降舵合为一体成为全动平尾。垂直尾翼包括固定的垂直安定面和可动的方向舵。尾翼的作用是操纵飞机俯仰和偏转，保证飞机能平稳飞行。　　

4.起落装置--飞机的起落架大都由减震支柱和机轮组成，作用是起飞、着陆滑跑，地面滑行和停放时支掌飞机。　　

5.动力装置--动力装置主要用来产生拉力和推力，使飞机前进。其次还可为飞机上的其他用电设备提供电源等。现在飞机动力装置应用较广泛的有：航空活塞式发动机加螺旋桨推进器、涡轮喷气发动机、涡轮螺旋桨发动机和涡轮风扇发动机。除了发动机本身，动力装置还包括一系列保证发动机正常工作的系统。　　

*飞机上除了这五个主要部分外，根据飞机操作和执行任务的需要，还装有各种仪表、通讯设备、领航设备、安全设备等其他设备。

二、飞机的升力和阻力
　　
飞机是重于空气的飞行器，当飞机飞行在空中，就会产生作用于飞机的空气动力，飞机就是靠空气动力升空飞行的。在了解飞机升力和阻力的产生之前，我们还要认识空气流动的特性，即空气流动的基本规律。流动的空气就是气流，一种流体，这里我们要引用两个流体定理：连续性定理和伯努利定理流体的连续性定理：当流体连续不断而稳定地流过一个粗细不等的管道时，由于管道中任何一部分的流体都不能中断或挤压起来，因此在同一时间内，流进任一切面的流体的质量和从另一切面流出的流体质量是相等的。

连续性定理阐述了流体在流动中流速和管道切面之间的关系。流体在流动中，不仅流速和管道切面相互联系，而且流速和压力之间也相互联系。伯努利定理就是要阐述流体流动在流动中流速和压力之间的关系。伯努利定理基本内容：流体在一个管道中流动时，流速大的地方压力小，流速小的地方压力大。　　

飞机的升力绝大部分是由机翼产生，尾翼通常产生负升力，飞机其他部分产生的升力很小，一般不考虑。从上图我们可以看到：空气流到机翼前缘，分成上、下两股气流，分别沿机翼上、下表面流过，在机翼后缘重新汇合向后流去。机翼上表面比较凸出，流管较细，说明流速加快，压力降低。而机翼下表面，气流受阻挡作用，流管变粗，流速减慢，压力增大。这里我们就引用到了上述两个定理。于是机翼上、下表面出现了压力差，垂直于相对气流方向的压力差的总和就是机翼的升力。这样重于空气的飞机借助机翼上获得的升力克服自身因地球引力形成的重力，从而翱翔在蓝天上了。　　机翼升力的产生主要靠上表面吸力的作用，而不是靠下表面正压力的作用，一般机翼上表面形成的吸力占总升力的60-80%左右，下表面的正压形成的升力只占总升力的20-40%左右。　　

飞机飞行在空气中会有各种阻力，阻力是与飞机运动方向相反的空气动力，它阻碍飞机的前进，这里我们也需要对它有所了解。按阻力产生的原因可分为摩擦阻力、压差阻力、诱导阻力和干扰阻力。　　

1.摩擦阻力--空气的物理特性之一就是粘性。当空气流过飞机表面时，由于粘性，空气同飞机表面发生摩擦，产生一个阻止飞机前进的力，这个力就是摩擦阻力。摩擦阻力的大小，决定于空气的粘性，飞机的表面状况，以及同空气相接触的飞机表面积。空气粘性越大、飞机表面越粗糙、飞机表面积越大，摩擦阻力就越大。　　

2.压差阻力--人在逆风中行走，会感到阻力的作用，这就是一种压差阻力。这种由前后压力差形成的阻力叫压差阻力。飞机的机身、尾翼等部件都会产生压差阻力。　　

3.诱导阻力--升力产生的同时还对飞机附加了一种阻力。这种因产生升力而诱导出来的阻力称为诱导阻力，是飞机为产生升力而付出的一种“代价”。其产生的过程较复杂这里就不在详诉。　　

4.干扰阻力--它是飞机各部分之间因气流相互干扰而产生的一种额外阻力。这种阻力容易产生在机身和机翼、机身和尾翼、机翼和发动机短舱、机翼和副油箱之间。　　

以上四种阻力是对低速飞机而言，至于高速飞机，除了也有这些阻力外，还会产生波阻等其他阻力。

三、影响升力和阻力的因素
　　
升力和阻力是飞机在空气之间的相对运动中（相对气流）中产生的。影响升力和阻力的基本因素有：机翼在气流中的相对位置（迎角）、气流的速度和空气密度以及飞机本身的特点（飞机表面质量、机翼形状、机翼面积、是否使用襟翼和前缘翼缝是否张开等）。　　

1.迎角对升力和阻力的影响--相对气流方向与翼弦所夹的角度叫迎角。在飞行速度等其它条件相同的情况下，得到最大升力的迎角，叫做临界迎角。在小于临界迎角范围内增大迎角，升力增大：超过临界临界迎角后，再增大迎角，升力反而减小。迎角增大，阻力也越大，迎角越大，阻力增加越多：超过临界迎角，阻力急剧增大。　　

2.飞行速度和空气密度对升力阻力的影响--飞行速度越大升力、阻力越大。升力、阻力与飞行速度的平方成正比例，即速度增大到原来的两倍，升力和阻力增大到原来的四倍：速度增大到原来的三倍，胜利和阻力也会增大到原来的九倍。空气密度大，空气动力大，升力和阻力自然也大。空气密度增大为原来的两倍，升力和阻力也增大为原来的两倍，即升力和阻力与空气密度成正比例。　　

3，机翼面积，形状和表面质量对升力、阻力的影响--机翼面积大，升力大，阻力也大。升力和阻力都与机翼面积的大小成正比例。机翼形状对升力、阻力有很大影响，从机翼切面形状的相对厚度、最大厚度位置、机翼平面形状、襟翼和前缘翼缝的位置到机翼结冰都对升力、阻力影响较大。还有飞机表面光滑与否对摩擦阻力也会有影响，飞机表面相对光滑，阻力相对也会较小，反之则大。

航空气象知识

2009-04-06T22:09:00.001+08:00

影响飞行安全的危险天气——风切变

风切变即是在短距离内风向、风速发生明显突变的状况。强烈的风切变瞬间可以使飞机过早地或者被迫复飞。在一定条件下还可导致飞机失速和难以操纵的危险，甚至导致飞行事故。

影响飞行安全的危险天气——吹雪

当地面有积雪，强风将积雪吹起飞舞在近地面空中的现象，使得能见度小于10公里，如果雪片被风吹起，高度超过2米，称为高吹雪，如果高度不超过2米，称为低吹雪。

影响飞行安全的危险天气——雷雨

雷雨是在强烈垂直发展的积雨云内所产生的一种天气现象，这种现象除有较强的降水外，同时还伴有雷声、问电和风的骤变，有时还伴有冰雹。雷雨有以下几类：气团性雷雨分对流性雷雨和地形雷雨；锋面雷雨分为冷锋、锋前、暖锋、静止锋、高空锋雷雨。雷雨对飞行的影响：雷雨产生颠簸（包括上升、下降气流）、结冰、雷电、冰雹和飑，均给飞行造成很大的困难，严重的使飞机失去控制、损坏、马力减少等危险。

影响飞行安全的危险天气一一结冰

飞机在温度0℃以下的云中飞行时，往往在飞机的外表通风面上凝结冰霜，这种现象叫飞行结冰。在温度低于零度（特别是在0℃至10℃）的云中，存在着大量的过冷水滴。过冷水滴是很少稳定的，一受到震动，就会冻结。当飞机机体表商的温度低于0℃时，碰上些冷水滴，就会产生积冰。结冰对飞行是很危险的。由于冰霜的聚积增加了飞机的重量，更重要的是因为机翼流线型的改变，螺旋桨叶重量的不平衡，或者是汽化器中进气管的封闭，起落架收放困难，无线电天线失去作用，汽化器减少了进气量，降低了飞机马，还可使油门冻结，断绝了油料来源，驾驶舱窗门结冰封闭驾驶员的视线等原因造成飞机失事危险是可以想象的。结冰的形态可以分为明冰、毛冰与雾凇三种。明冰和毛冰最危险。因其牢固，不易排除，而且增长极为迅速，成为最危险的一种积冰。

影响飞行安全的危险天气一一颠簸

颠簸的危害：飞行时的颠簸主要是由于空气的不规则的垂直运动，使飞机上升下沉，由于热力原因造成的颠簸，如午后或太阳辐射最强烈时的颠簸。动力原囚造成的颠簸产生在风切变和强度的气旋流动中。严重的颠簸可使机翼负荷加大而变形甚至折断，或使飞机下沉或上升几百米高度的危险。

影响飞行安全的危险天气一一台风

台风是热带风暴的一种，发源于接近赤道的海洋上，在适当的条件下，就可以由低压发展成强烈的风暴。台风中飞行，可遇到严重的颠簸，大雨和恶劣的能见度，猛烈的风暴和在着陆时近地面有阵风等危险天气。

影响飞行安全的危险天气——雾

雾是大量的大水滴或小冰晶浮游在近地面空气层中，致使能见度减小的现象。按其浓度分为浓雾和轻雾两种，浓雾雾滴浓度、水平能见度小于1 00O米；轻雾雾滴的密度比浓雾小，水平能见度大子1 千米，小于10千米。雾与低云同样不利于飞行，不仅使云高近于零，而且在有浓雾时，能见度也近于零。云雾同样均为极细微水滴所组成，在结冰温度以下时，亦可为冰晶所组成。其水点为雨滴的十分之一至百分之一。云雾之分在于云贴近地面即为雾，雾离地面即为云。雾主要分为气团雾和锋面雾等。

确定飞行姿态

2009-04-06T22:07:00.000+08:00

飞机在空中飞行与在地面运动的交通工具不同，它具有各种不同的飞行姿态。这指的是飞机的仰头、低头、左倾斜、右倾斜等变化。

飞行姿态决定着飞机的动向，既影响飞行高度，也影响飞行的方向。低速飞行时，驾驶员靠观察地面，根据地平线的位置可以判断出飞机的姿态。但由于驾驶员身体的姿态随飞机的姿态而变化，因此这种感觉并不可靠。

例如当飞机转了一个很小角度的弯，机身倾斜得很厉害，驾驶员一时不能很快地调整好自己的平衡感觉，从而不能正确地判断地平线的位置，就可能导致飞机不能恢复到正确的飞行姿态上来。还有飞机在海上做夜间飞行，漆黑的天空与漆黑的大海同样都会闪烁着星光或亮光。在这茫茫黑夜中很难分辨哪里是天空，哪里是大海，稍有失误，很容易就把飞机开进海中。

为了飞行的安全，极有必要制作出一种能指示飞机飞行姿态的仪表。这块仪表必须具有这样一种性能，即能够显示出一条不随着飞机的俯仰、倾斜而变动的地平线。在表上这条线的上方即为天，下方即为地。天与地都分别用不同的颜色予以区别，非常醒目。怎样才能造出这条地平线呢?设计者从玩具陀螺中获得了灵感。

许多小孩都玩过陀螺。它的神奇之处在于当它转动起来以后，无论你如何去碰它，它总是保持直立姿态，决不会躺倒。而且它转的越快，这种能保持直立的特性就越强。换句话说：陀螺转动起来后，它可以保持它的旋转轴的指向不受外界的干扰，指向它起始的方向。

利用这个原理，在l9世纪末就制造出来陀螺仪，它的核心部分是一个高速转动的陀螺，专业术语叫转子。把转子装在一个各方向均可自由转动的支架上，这就是陀螺仪。把陀螺仪安装到其他设备上，不管这个设备如何运动，陀螺仪内转子旋转轴的方向是不会改变的。飞机发明后不久，陀螺仪就被用到了飞机上。把陀螺仪的支架和机身连在一起，它的转子在高速旋转时，旋转轴垂直于地面，有一根横向指示杆和转子轴垂直交叉相连。

飞机可以改变飞行姿态，但转子轴会始终指向地面，横向标示杆就始终和地平线平行，它在仪表中被叫做人造地平线，这个仪表被称为地平仪，也叫姿态指引仪。在实际飞行时，驾驶员在任何时都应相信地平仪指示出的飞行姿态而不是相信自己的感觉判断，从而避免因飞机的剧烈俯仰倾斜动作导致的判断失误，这样才能保证飞机安全飞行。

测量飞行的高度、速度和方向

2009-04-06T22:04:00.000+08:00

驾驶员用眼虽然也可以估计出飞机与地面的距离，但这样得出的结论很不准确。而且当光线不好或飞机飞得很高时，用目测高度就根本不可能。用大气压力变化与高度相关的原理，制造出的飞机高度表解决了这个问题。

大气压力是由空气的重量堆积而成的，越到高处空气的厚度就越小，气压就越低。随着高度的增加，气压线性下降。如果在飞机上能测出外面的气压，当然就可以换算出飞机此刻的飞行高度。飞机上现在装的就是以这样原理做的气压表，但表盘上显示出的数字却是经过换算出来的高度，这就方便于驾驶员的使用了。

飞机在空中飞行，驾驶员不仅要知道飞机对地面运动的速度(地速)，而且还要知道飞机相对于空气运动的速度（空速）。下面先解释一下对飞机来说比较重要的空速。机翼的升力来自于流过的机翼上下表面气流的速度差，因此空速决定了升力的大小。空速越大，升力F越大；没有空速，升力消失，飞机就会从天上掉下来。相对于飞机来说，空气流动的越快，对飞机冲击的压力也越大，这个压力被称之为动压。动压与空速相关，当动压被测出后也就可以换算出空速。

测量空速的系统由三部分组成。第一部分叫全压管。它是一根向飞行前方伸出的管子，被装在机头或翼尖上。当空气迎面吹过来流入管中，在管子的后部就可以感受到流入空气的全部压力。这个压力由空气流入管内的动压和空气静止时内部的静压组成。第二部分是静压孔。静压孔是开在机身侧方不受气流干扰的一些小孔。空气从这里缓慢流人孔内，这里的空气压力是静压。第三部分是压力表，表的一端与全压管相连，另一端与静压孔相连。压力表测得的数字是全压与静压之差，也就是动压。根据动压与空速的相关关系，就能将空速换算出来。

地速表明飞行中的飞机相对于地面运动的速度。地速是由空速加上空气本身的流速(风速)这两部分组成。空速、风速、地速都是可以是指向任何方向的矢量。当把它们加在一起时，三个矢量组成一个三角形，这就是有名的速度三角形。通过它，驾驶员就可以知道飞机的地速是多少了。

低速飞机在飞行时，驾驶员依靠观察地面的标志来辨别方向。一旦飞机升到云海之上或在海洋上空飞行时就找不到地面标志物了。借助于我们祖先的伟大发明之一——磁罗盘，这个问题就解决了。在飞机上的这个磁罗盘(指南针)是经过改装的，叫做航向仪。

因为飞机飞行速度很快，沿地表面飞行时，尽管乘客感受不到地球的弯曲弧度，但磁罗盘却会感觉到这种变化。飞机沿着地表曲度不断变化着姿态，如果磁罗盘的运动赶不上这种变化速度，那么它指出的就是错误方向。为此在磁罗盘上还要附加一套陀螺，这样才能使磁罗盘一直保持与地面平行的姿态，为飞机指明正确的方向。这一整套装置叫航道罗盘。

飞机座椅与安全

2009-04-06T22:00:00.002+08:00

一般人会认为：飞机客舱应是飞机上最简单的部分，安排上足够的座椅不就行了吗。但事情并非如此简单。客机是为旅客服务的。旅客对某架飞机印象的好坏，很大一部分是从客舱得来的。旅客不满意的话，这种飞机的销路就不好。因此飞机制造厂与航空公司都在飞机的客舱上下了很大功夫。
旅客进入客舱后，主要的活动都在座椅上进行，因此必然对座椅有一定的要求。座椅首先是应该安全坚固的，其次要让旅客坐着舒服。飞机在加速时，旅客会被惯性向后压，座椅会承受向后的压力；而在飞机因故紧急减速时，座椅又会受到向前的作用力。如果座椅的性能不好，就可能导致旅客身体受到伤害。因此座椅在强度上必须能耐受住巨大的冲击力作用。

理论上讲，飞机不会突然加速，但会突然紧急减速，因此惯性使旅客前冲的可能很大。如果安排旅客都面朝后坐，向前的冲力转移到椅背上，旅客就会安全一些。但是实际上，按照旅客的心理，几乎没有人愿意面向后坐。人总是愿意面朝前对正将要飞去的地方，而不喜欢看着飞过的地方向远方退去。

多数军事运输飞机为了安全，把座椅面向后安装，、而客机的座位却总是面朝前安装的。怎么才能解决它的安全问题呢?加装在座椅上的安全带就起了很大的作用。它与座椅紧紧连接，可以调节长度，用卡扣把乘客“捆绑”在座椅上。

在飞机起飞、降落或遇到空中气流颠簸时，旅客都必须系好安全带。它的作用不仅司以防止乘客向前冲，还可以防止飞机急速下降时乘客受惯性作用被向上抛起。搭乘飞机的旅客一定不要忽视安全带的作用，要听从机上的广播或乘务员的指令系好安全带。

几年前，曾有一架飞机在北美上空突然因故下降了1000多米，机上208多名乘客凡是系好安全带的人都安然无恙，而未系好安全带的旅客有100多名都受到了不同程度的伤害。

乘飞机时，每个旅客都需要一定的活动空间，空间大，旅客就越会感到舒适。大型客机为照顾不同要求的旅客，按座位所占空间的大小把座舱分为头等舱、公务舱和经济舱3类。以波音747为例：它的头等舱每一排有4个座位，前排与后排间隔96．5厘米。这么大的空间可以使乘客选择放倒椅背让身体处于半躺半卧的舒适状态；公务舱每一排为6个座位，排间距为86．3厘米；经济舱每一排有10个座位，排间距为81．3厘米，乘客面前的空间只能勉强让另一名乘客通过。

头等舱的票价比经济舱会贵很多。在相同的空间内，经济舱内的76座位比头等舱要多两倍以上。飞机越小，客舱座位划分的等级也越少，中小型飞机一般只设经济舱。

为什么不把座椅的间距再缩小一点以便多搭载一些乘客，赚更多的钱呢?这是有原因的，从安全上考虑一旦飞机出现紧急情况，乘客必须迅速撤离飞机。国际民航组织规定：大型客机在一分钟之内必须把所有旅客全部撤离。如果座位间的距离太小，就不能达到上述要求。为此而规定：座位间距离不能小于73．7厘米(29英寸)。

实际情况是除了某些做短途飞行、机上服务很少的小型飞机外，大中型客机都不采用这种最低标准的座间距离。从舒适角度考虑，窄间距的座位配置不仅使长途旅客感到非常不舒服，甚至这种不舒服的姿势会导致旅客发生疾病。

安全考虑也用于客舱通道的安排上。一条纵贯机身的通道必然会占用很大的空间，特别是对于机身较窄的飞机来说更是如此。但即使是这样，这条通道也不能因经济方面的考虑而被挤占。在通道的每侧最多只能安置3个座位，这样坐在最靠窗的乘客只要越过2个乘客的座位就可以走到通道上来。

20世纪70年代初，航空公司开始使用载客250人以上的大型客机参加运营。这类飞机的机身宽度都增加了，每一排的座位都在6个以上，于是就安排2条通道。每条通道的靠窗一侧仍安排3个座位，2条通道之间最多可以安放6个座位。

但现有的大型客机中，2条通道之间安排座位最多的是波音777飞机，它安排了5个座位。客舱内只有一条通道的飞机叫窄体客机，两条通道的飞机叫宽体客机。

飞行原理简介（一）

2009-04-06T21:40:00.002+08:00

飞机的每次飞行，不论飞什么课目，也不论飞多高、飞多久，总是以起飞开始以着陆结束。起飞和着陆是每次飞行中的两个重要环节。所以，我们首先需要掌握好起飞和着陆的技术。

一. 滑行飞机不超过规定的速度，在地面所作的直线或曲线运动叫滑行。对滑行的基本要求是：飞机平稳地开始滑行，滑行中保持好速度和方向，并使飞机能停止在预定的位置。飞机从静止开始移动，拉力或推力必须大于最大静摩擦力，故飞机开始滑行时应适当加大油门。

飞机开始移动后，摩擦力减小，则应酌量减小油门，以防加速太快，保持起滑平稳。滑行中，如果要增大滑行速度，应柔和加大油门，使拉力或推力大于摩擦力，产生加速度，使速度增大，要减小滑行速度，则应收小油门，必要时，可使用刹车。

二. 起飞飞机从开始滑跑到离开地面，并升到一定高度的运动过程，叫做起飞。飞机起飞的操纵原理飞机从地面滑跑到离地升空，是由于升力不断增大，直到大于飞机重力的结果。而只有当飞机速度增大到一定时，才可能产生足以支持飞机重力的升力。可见飞机的起飞是一个速度不断增加的加速过程。；剩余拉力较小的活塞式螺旋桨飞机的起飞过程，一般可分为起飞滑跑、离地、小角度上升（或一段平飞）、上升四个阶段。

对有足够剩余拉力的螺旋桨飞机，或有足够剩余推力的喷气式飞机，因可使飞机加速并上升，故起飞一般只分三个阶段，即起滑跑、离地和上升。

（一）起飞滑跑的目的是为了增大飞机的速度，直到获得离地速度。拉力或推力愈大，剩余拉力或剩余推力也愈大，飞机增速就愈快。起飞中，为尽快地增速，应把油门推到最大位置。

1.抬前轮或抬尾轮

* 前三点飞机为什么要太前轮？前三点飞机的停机角比较小，如果在整个起飞滑跑阶段都保持三点姿态滑跑，则迎角和升力系数较小，必然要将速度增大到很大才能产生足够的升力使飞机离地，这样，滑咆距离势必很长。因此，为了减小离地速度，缩短滑跑距离，当速度增大到一定程度时就需要抬起前轮作两点姿态滑跑，以增大迎角和升力系数。

* 抬前轮的时机和高度抬前轮的时机不宜过早或过晚。抬前轮过早，速度还小，升力和阻力都小，形成的上仰力矩也小。要拾起前轮，必须使水平尾翼产生较大的上仰力矩，但在小速度情况下，水平尾翼产生的附加空气动力也小，要产主足够的上仰力矩就需要多拉杆。结果，随着滑跑速度增大，上仰力矩又将迅速增大，飞行员要保持抬前伦的平衡状态，势必又要用较大的操纵量进行往复修正，给操纵带来困难。同时，抬前轮过旱，使飞机阻力增大而增长起飞距离。

如果抬前轮过晚，不仅使滑跑距离增长，而且还由于拉杆抬前轮到离地的时间很短，飞行员不易修正前轮抬起的高度而保持适当的离地迎角。甚至容易使升力突增很多而造成飞机猛然离地。

各型飞机抬前轮的速度均有其具体规定。前轮抬起高度应正好保持飞机离地所需的迎角，前轮抬起过低，势必使迎角和升力系数过小，离地速度增大，滑跑距离增长，前轮抬起过高，滑跑距离虽可缩短，但因飞机阻力大，起飞距离将增长，而且迎角和升力系数过大，又势必造成大迎角小速度离地，离地后，飞机的安定住差操纵性也不好。

仰角过大，还可能造成机尾擦地。从既要保证安全又要缩短滑跑距离的要求出发，各型飞机前轮抬起高度都有其具体规定。飞行员可从飞机上的俯仰指示器或从机头与天地线的关系位置来判断前轮抬起的高度是否适当。

* 后三点飞机为什么要抬尾轮后三点飞机与前三点飞机相比，停机角比较大，因此三点滑跑中迎角较大，接近其临界迎角，如果整个滑跑阶段都保持三点滑跑，升力系数比较大，飞机在较小的速度下即能产生足够的升力使飞机离地。此时滑跑距离虽然很短，但大迎角小速度离地后，飞机安定性操纵性都差，甚至可能失速。因此后三点飞机，当滑跑速度增大到一定时，飞行员应前推驾驶杆，抬起机尾作两点滑跑，以减小迎角。

与前三点飞机抬前轮一样，为了既保证安全，又缩短滑跑距离，必须适时正确地抬机尾。抬机尾过早或过晚，过高或过低，不仅会增长滑跑距离，起飞距离，而且会危及飞行安全。各型飞机抬机尾的速度和高度也都有其具体规定。

2. 保持滑跑方向对螺旋桨飞机而言，起飞滑跑中引起飞机偏转的主要原因是螺旋桨的副作用。起飞滑跑中，螺旋桨的反作用力矩力图使飞机向螺旋桨旋转的反方向倾斜，造成两主轮对地面的作用力不等，从而使两主轮的摩擦力不等，两主轮摩擦力之差对重心形成偏转力矩。螺旋桨滑流作用在垂直尾翼上也产主偏转力矩。

前三点飞机抬前轮时和后三点飞机抬尾轮时，螺旋桨的进动作用也会使飞机产生偏转。加减油门和推拉笃驶杆的动作愈粗猛，螺旋桨副作用影响愈大。为减轻螺旋桨副作用的影响，加油门和推拉驾驶杆的动作应柔和适当。滑跑前段，因舵的效用差，一般可用偏转前轮和刹车的方法来保持滑跑方向。滑跑后段应用舵来保持滑跑方向。随着滑跑速度的不断增大，方向舵的效用不断提高，就应当回舵，以保持滑跑方向。

喷气飞机起飞滑跑方向容易保持，其原因是；一是喷气飞机都是前三点飞机，而前三点飞机在滑跑中具有较好的方向安定住，二是没有螺旋桨副作用的影响，所以在加油门和抬前轮时，飞机不会产主偏转。

（二）当速度增大到一定，升力稍大于重力，飞机即可离地。离地时作用于飞机的力。此时升力大于重力，拉力或推力大于阻力。

离地时的操纵动作，前三点飞机和后三点是不同的。前三点飞机是因飞行员拉杆产生上仰操纵力矩，而使飞机作两点滑跑的。随着滑跑速度的增大、上仰力矩增大，迎角将会增大。虽然飞行员不断向前推杆以保持两点滑跑姿态，但原来的俯仰力矩平衡总是随速度的增大而不断被破坏，在到达离地速度时，迎角仍会有自动增大的趋势。所以，前三点飞机一般都是等其自动离地。

后三点飞机则不然，飞机到达离地速度时，一般都需带杆增大迎角而后离地。这是因为后三点飞机在两点滑跑中，飞行员是前推杆，下偏升降舵来保持的，随着速度增大，下俯操纵力矩增大，将使迎角减小，飞行员虽不断带杆以保持两点滑跑，但在到达离地速度时，迎角仍会有减小的趋势。所以，必须向后带杆增大迎角飞机才能离地。

后三点飞机，正确掌握离地时机是很重要的。离地过早或过晚，都将给飞行带来不利。机轮离地后，机轮摩擦力消失，飞机有上仰趋势，应向前迎杆制止。对螺旋浆飞机，机轮摩擦力矩也消失，飞机有向螺旋桨旋转方向偏转的趋势，应用舵制止。

（三）一段平飞或小角度上升对剩余拉力比较小的活塞式螺旋浆飞机，飞机离地还尚未达到所需的上升速度，故需作一段平飞或小角度上升来积累速度。飞机离地后在12米高度向前迎杆，减小迎角，使飞机平飞加速或作小角度上升加速。飞机刚离地时，不宜用较大的上升角上升。上升角过大，这会影响飞机增速，甚至危及安全。

为了减小阻力，便于增速，飞机高地后，一般不低于5米高度收起落架。收起落架时机不可过早或过晚。过早，飞机离地大近，如果飞机有下俯，就可能重新接地，危及安全；过晚，速度大大，起落架产生的阻力很大，不易增速，还可能造成起落架收下好。在一段平飞或小角度上升中，特别要防止出现坡度，因为这时飞行高度低，飞机如有坡度，就会向下侧滑而可能使飞机撞地。因此发现飞机有坡度应及时纠正。

（四）当速度增加到规定时，应柔和带杆使飞机转入稳定上升，上升到规定高度起飞阶段结束。 ***影响起飞滑跑距离的因素影响起飞滑跑距离的困素有油门位置、离地迎角、襟翼反置、起飞重量、机场标高与气温、跑道表面质量、风向风速、跑道坡度等。这些因素一般都是通过影响离地速度或起飞滑跑的平均加速度来影响起飞滑跑距离的。

* 油门位置油门越大，螺旋桨拉力或喷气推力越大，飞机增速快，起飞滑跑距离就短。所以，一般应用最大功率或最大油门状态起飞。

* 离地迎角离地迎角的大小决定于抬前轮或抬机尾的高度。离地迎角大，离地速度小，起飞滑跑距离短。但离地迎角又不可过大，离地迎角过大，下仅会因飞机阻力大而使飞机增速慢延长滑跑距离，而且会直接危及飞行安全因此从既要保证飞行安全又要使滑跑距离短出发，各型飞机一般都规定有最有利的离地迎角值。

* 襟翼位置放下襟翼，可增大升力系数，减小离地速度，因而能缩短起飞滑跑距离。

* 起飞重量起飞重量增大，不仅使飞机离地速度增大，而且会引起机轮摩擦力增加，使飞机不易加速。因此，起飞重量增大，起飞滑跑距离增长。

* 机场标高与气温机场标高或气温升高都会引起空气密度减小，一放面使拉力或推力减小，飞机加速慢；另一方面，离地速度增大，因此起飞滑跑距离必然增长。所以在炎热的高原机场起飞，滑跑距离显著增长。

* 跑道表面质量不同跑道表面质量的摩擦系数，滑跑距离也就不同。跑道表面如果光滑平坦而坚实，则摩擦系数小，摩擦力小，飞机增速快，起飞滑跑距离短。反之跑道表面粗糙不平或松软，起飞滑跑距离就长。

* 风向风速起飞滑跑时，为了产生足够的升力使飞机离地，不论有风或无风，离地空速是一定的。但滑跑距离只与地速有关，逆风滑跑时，离地地速小，所以起飞滑跑距离比无风时短。反之则长。

* 滑跑坡度跑道有坡度，会使飞机加速力增大或减小。

三. 着陆

飞机从一定高度下滑，井降落地面滑跑直至完全停止运动的整个过程，叫着陆。

飞机着陆的操纵原理

与起飞相反，着陆是飞机高度下断降低、速度不断减小的运动过程。飞机从一定高度作着陆下降时，发动机处于慢车工作状态，即一般采用带小油门下滑的方法下降。飞行高度降低到接近地面时，必须在一定高度上开始后拉驾驶杆，使飞机由下滑转入平飘这就是所谓“拉平”。

机拉平后，飞机速度仍然较大，不能立即接地．需要在离地0．5～1米高度上继续减小速度，这个拉平后继续减小速度的过程，就是平飘。在这个过程中，随着飞行速度的不断减小，飞行员不断后拉驾驶杆以保持升力等于重力。在离地0．15～0．25米时，将飞机拉成接地所需的迎角，升力稍小于重力，飞机轻柔飘落接地飞机接地后，还需要滑跑减速直至停止，这个滑跑减速过程就是着陆滑跑。由上可见，飞机着陆过程一般可分为五个阶段：下滑段、拉平段、平飘段、接地和着陆滑跑段。

拉平

拉平是飞机由下滑转入平飘的曲线运动过程，即飞机由下滑状态转入近似平飞状态的过程。为完成这个过程，飞行员应拉杆增加迎角：使升力大于重力第一分力，此两力之差为向心力，促进飞机向上作曲线运动，减小下滑角。对某些飞机，因放襟翼后，上仰力矩较大，下滑中通常是向下顶杆以保持飞机的平衡，所以开始拉平时只需松杆，后再逐渐转为拉杆。拉杆或松杆增大迎角，阻力也同时增大，且因下滑角不断减小，重力也跟着减小，所以阻力大于重力飞行速度不断减小。

可见飞机在拉平阶段中，下滑角和下滑速度都逐渐减小，同时高度不断降低。飞行员应根据飞机的离地和下沉接近地面的情况，掌握好拉杆的分量和快慢，使之符合客观实际，才能做到正确的拉平。如高度高、下沉慢、俯角小，拉杆的动作应适当慢一些；反之，高度低、下沉快、俯角大，拉杆的动作应适当快一些。

飞机上典型乘客们的七种类型

2009-04-06T20:18:00.000+08:00

一、瞌睡型
　　
这种人与清醒有仇，与站立有恨，只有躺着才是他们最亲密的伙伴。他们一上飞机，连座号都不看，先问空姐座位满不满。只要一听说不满，他们必定走到后排，找三个连着的座椅，把扶手打开，往上面一躺，安全带一系，再要个毛毯当枕头，很快就鼾声响起，进入梦乡。梦到关键时刻，个别人还不忘吧唧几下嘴巴——如此情形，俺明白，那是表示自己睡得很香，请勿打扰！
　　
二、休闲型
　　
这种人一坐下来，就摸出耳机戴上，甭管是ＭＰ３，还是飞机上视听设备，反正已经开始闭目养神了，“两耳不闻窗外事，一心只想私生活”。偶尔空姐前来打扰，问他要不要饮料或者用餐，他会不解地张大嘴巴，以１３５分贝的声音问：“你说啥？”他的话音未落，整个飞机就像受了不稳定气流的干扰，剧烈地摇摆外加颤动——如此情形，你会以为又一位“怕瓦落地”诞生了。
　　
三、聊天型
　　
一上飞机，这种人就开始寻找聊天的对象。第一选择当然是同伴，没有同伴就选旁边的漂亮美眉，实在不行，帅哥也凑合了。坐下之后，甭管对象是谁，逮着就会侃个没完。从一瓶酱油到原子弹，从萨达姆到两支香烟，上下五千年，纵横十万里，跨度大，范围广，广征博引，穷尽古籍，唾沫星子满天飞。他完全是抢时间，拼速度，锱铢必较，只争朝夕，仿佛一停下来，这飞机便要自由落体——如此情形，你会觉得如果联合国派他去中东斡旋，哪会发生战争？双方的领导都被他啰嗦死了。
　　
四、旅游型
　　
这种人上了飞机，说啥也要换个靠窗的座位，然后掏出数码相机，从飞机起飞一直到降落，绝对不会闲着，一阵狂拍外加一段评论。这里好，那里差，这里有森林，那里有西瓜。飞机在云层中穿行时，个别人透过窗子，会突然发现远处有一座山，山是那样的高而且那样的远，他激动地大叫：“我看见珠穆朗玛峰了！”——如此情形，俺闭着眼睛都知道，那是一团黑色的云。
　　
四、没事找事型
　　
这种人一上飞机，空姐们肯定无法休息了。他们坐下来后，就嚷着要毛毯；毛毯到手，要报纸；报纸拿上，还要张旅客登记表。填过登记表，开始要饮料，饮料点出一长串，飞机上都没有。换了七八种，才说到飞机有的，空姐赶紧去拿，交到手中，他又饿了，让给准备。空姐有米饭，他说要炒饭；说有面条，他说要凉面或者莜面，急得空姐直冒汗，他却潇洒地递上名片——如此情形，他不给名片，俺也知道他姓麻，叫麻烦。
　　
六、四海为家型
　　
此种人基本上是航空公司的ＶＩＰ客户、金卡会员，有着丰富的乘坐经验。找到座位，打开包，掏出拖鞋。把沉重的皮鞋脱下，穿上拖鞋。偶尔还盘腿大坐，像在自家炕头上。然后旁若无人地开始吃瓜子、花生、膨化食品，就像坐在自己的厨房里。如果遇到汗脚且自我感觉良好者，整个封闭的空间瞬时就充满了海鲜味——如此情形，每每令人联想到一句成语：臭名远扬，而且是飞机能飞多远，臭就扬多远。
　　
七、工作第一型
　　
一旦飞机起飞稳定，这种人就开始工作。起身翻找行李，拿出笔记本电脑。打开了，先看报表；看完了写文件，不是汇报就是建议书，要么就是总结或者计划，反正总有干不完的活，估计也有挣不完的钱，数不完的钞票。写到兴奋时，还能自我陶醉，投入地闭眼，手托着腮再度沉思。然后蓦地抬头，对空姐说：“拿去打印一下。”——如此情形，他把空姐当成了办公室的秘书……

飞行员的飞行全过程

2009-04-06T20:05:00.001+08:00

为了使大家了解飞行，这里，我们模拟一架波音飞机飞行上海的航班来看看飞行的一部分。

在接到飞行任务后，机长和副驾驶在飞行前一天的下午来到飞行情报室进行飞行前的准备。主要是熟悉所飞航线的导航数据、降落及备降机场的使用细则、飞行程序，并且在准备完后与机组其他成员一起就明日的飞行做出详细分工安排。

清晨，机长按照航班时刻，提前1小时来到飞机上。副驾驶已将飞机里加入所需的航空燃油，并完成了飞机驾驶舱的初步准备工作，包括完成在飞行管理计算机里输入今日飞行的主要数据，等待机长进行检查。乘务员们也来到飞机上，机上共有5名乘务员，她们在乘务长的安排下对客舱、旅客餐食、机上供应品进行准备。

大约在起飞前25分钟时，旅客们开始登机。机长和副驾驶各自坐在飞机驾驶舱的左右驾驶座上。机长打开了“系好安全带”的信号，设置了飞机停留刹车，开始对飞行管理计算机的内容进行检查。

飞行管理计算机里存储了航空公司所飞航班的大部分信息，飞行员仅需要输入相应代码即可，计算机会自动生成航路。今天共有168名乘客，飞机的起飞重量为102吨，副驾驶根据舱单（客货装载表）在计算机里输入了起飞速度。15分钟后，机长确认了准备工作已完成，在驾驶舱的显示器上已表明所有飞机舱门都已关好，乘务长报告客舱准备完毕。

机长示意副驾驶向机场指挥塔台请示启动发动机，塔台同意了。飞机在五分钟后启动好发动机并在塔台的同意下开始滑行。飞机在启动发动机时就开始在航空管制员的指挥下进行工作，塔台就是机场自身的航空管制站。飞机滑行时，乘务员正在对旅客进行航空安全的广播和示范，逐一检查旅客系安全带的情况。

飞机已经滑行到跑道上，机组向客舱发出了起飞的信号。按照准备时的约定，这个起飞动作由副驾驶完成，机长把飞机对正跑道后将飞机交给副驾驶操纵。

飞机开始在跑道上滑跑，副驾驶全神贯注地操纵着飞机，当飞机速度加速到80海里时，机长按程序发口令“80海里”，副驾驶回答“检查”以确定飞机处于操纵之中。“V1”（决断速度）、“抬轮”，副驾驶按口令将飞机前轮抬起，这时飞机速度大约为270公里每小时。几秒种后，飞机离地开始上升。两台马力强劲的喷气式（英国制造）发动机使飞机以每秒15~20米的速度冲向云霄。

飞机离地后，机长配合副驾驶将飞机起落架和用于增加升力的襟翼收回以减少上升阻力，副驾驶则接通了3部自动驾驶仪其中的1部，让飞机自动驾驶。15分钟后，飞机开始在1万米左右的高空平飞。

飞行计算机显示，此时的高空风向为西风，速度为130公里每小时，所以飞机由于顺风的缘故，地速达到了980公里每小时。飞机的航向正飞向航线上的一个航路点，此时的飞机由安装在飞机上的惯性基准系统并参考地面全向信标导航台来定位。

飞越了一个航路点后，飞机自动转弯并飞向下一点，副驾驶向地区区域航空管制员报告了位置和高度，管制员在雷达上进行了确认。机长和副驾驶在整个平飞过程中始终严密监视着驾驶舱内的几块显示器，它们显示着飞机各个系统的运转情况。

与此同时，客舱内显得十分舒适。空调系统自动将环境温度调节到适宜的程度，舱顶上的液晶显示器将飞机的现在位置标在地图上，该液晶显示器在大部分时间里向乘客播映录像节目。在飞机的两个厨房里，几名乘务员忙着配餐、调制饮料。普通舱和头等舱的旅客们有的在休息，有的则通过窗欣赏空中景色。新式的机上卫生间内加装有为残疾人士和带有婴儿的父母使用的设施。旅客们将在机舱内度过4个小时。

飞行了3小时30分左右，副驾驶已经与上海地区区域航空管制员取得了联系，机长则从无线电里收听上海机场的最新航空通告，以便得到最新的天气和机场跑道情况。客舱的显示器上已经显示了预计达到的时间，乘务员们开始进行着陆前的准备工作。为了安全，机上的卫生间在着陆前20分钟起关闭使用。“系好安全带”的信号灯伴随着咚的一声闪亮了。

飞机开始下降。自动飞行系统将油门收至慢车位，飞机机头下俯，以10~15米每秒的下降率下降。客舱增压系统自动调整客舱气压以适应着陆机场气压。飞机沿预定航迹进入上海虹桥机场5号空中走廊，在4500米高度时通过了走廊口。此时，飞机距离机场70公里。机长继续操纵飞机实施进近程序，在距离机场25公里时开始减速，发出口令让副驾驶放出襟翼。在塔台的指挥下，飞机进近到跑道的延长线外15公里，起落架已放好。飞机自动着陆系统接收到了信号，但机长决定人工操纵飞机落地。飞机平稳地降落在跑道上。

飞机自动放出减速板减速，发动机也使用了反喷装置，加上自动刹车，速度很快减小到了滑行速度。机长操纵飞机脱离跑道沿滑行路线滑行，副驾驶启动了辅助动力装置使飞机在发动机熄火后仍提供足够的电力和空调供应。最后，飞机停靠在登机廊桥口，飞机停住了，机长关断了发动机，示意乘务员可以安排旅客下机了。旅客离机后，地面服务人员开始登机进行卫生清洁、餐食补给。而机外，数辆特种车辆正在给飞机加油、加水、处理污物、搬运行李货物，十分忙碌。

驾驶舱里，机长和副驾驶一起，开始对下一段航程进行充分的准备工作.....

八种航权简介

2009-04-06T19:12:00.010+08:00

第一航权：领空飞越权。
一国或地区的航空公司不降落而飞越他国或地区领土的权利。例如：北京—纽约，中途飞越日本领空，那就要和日本签订领空飞越权，否则只能绕道飞行。　　
第二航权：技术降落权。
一国或地区的航空公司在飞至另一国或地区途中，为非营运理由而降落其他国家或地区的权利，诸如维修、加油。例如：上海—芝加哥，由飞机机型的原因，不能直接飞抵，中间需要在安克雷奇加油，但不允许在安克雷奇上下旅客和货物。　　

第三航权：目的地下客权。
某国或地区的航空公司自其登记国或地区载运客货至另一国或地区的权利。例如：北京—东京，日本允许中国民航承运的旅客在东京进港。　　

第四航权：目的地上客权。
某国或地区的航空公司自另一国地区载运客货返回其登记国或地区的权利。例如：北京—东京，日本允许旅客搭乘中国民航的航班出境，否则中国民航只能空载返回。　　

第五航权：中间点权或延远权。
某国或地区的航空公司在其登记国或地区以外的两国或地区间载运客货，但其班机的起点与终点必须为其登记国或地区。也就是说，第五航权是要和两个或两个以上的国家进行谈判的。以新加坡航空公司的货机为例，它执飞新加坡经我国厦门、南京到美国芝加哥的航线，并在厦门、南京拥有装卸国际货物的权利。　　

第六航权：桥梁权。
某国或地区的航空公司在境外两国或地区间载运客货且中经其登记国或地区（此为第三及第四自由的结合）的权利。例如：伦敦—北京—汉城，国航将源自英国的旅客运经北京后再运到韩国。　　

第七航权：完全第三国运输权。
某国或地区的航空公司完全在其本国或地区领域以外经营独立的航线，在境外两国或地区间载运客货的权利。例如：伦敦—巴黎，由汉莎航空公司承运。　　

第八航权：国内运输权。
某国或地区的航空公司在他国或地区领域内两地间载运客货的权利（境内经营权）。例如：北京—成都，由日本航空公司承运。

FREEDOMS OF THE AIR

First Freedom of the Air - the right or privilege, in respect of scheduled international air services, granted by one State to another State or States to fly across its territory without landing (also known as a First Freedom Right).

Second Freedom of the Air - the right or privilege, in respect of scheduled international air services, granted by one State to another State or States to land in its territory for non-traffic purposes (also known as a Second Freedom Right).

Third Freedom of The Air - the right or privilege, in respect of scheduled international air services, granted by one State to another State to put down, in the territory of the first State, traffic coming from the home State of the carrier (also known as a Third Freedom Right).

Fourth Freedom of The Air - the right or privilege, in respect of scheduled international air services, granted by one State to another State to take on, in the territory of the first State, traffic destined for the home State of the carrier (also known as a Fourth Freedom Right).

Fifth Freedom of The Air - the right or privilege, in respect of scheduled international air services, granted by one State to another State to put down and to take on, in the territory of the first State, traffic coming from or destined to a third State (also known as a Fifth Freedom Right). ICAO characterizes all "freedoms" beyond the Fifth as "so-called" because only the first five "freedoms" have been officially recognized as such by international treaty.

Sixth Freedom of The Air - the right or privilege, in respect of scheduled international air services, of transporting, via the home State of the carrier, traffic moving between two other States (also known as a Sixth Freedom Right). The so-called Sixth Freedom of the Air, unlike the first five freedoms, is not incorporated as such into any widely recognized air service agreements such as the "Five Freedoms Agreement".

Seventh Freedom of The Air - the right or privilege, in respect of scheduled international air services, granted by one State to another State, of transporting traffic between the territory of the granting State and any third State with no requirement to include on such operation any point in the territory of the recipient State, i.e the service need not connect to or be an extension of any service to/from the home State of the carrier.

Eighth Freedom of The Air - the right or privilege, in respect of scheduled international air services, of transporting cabotage traffic between two points in the territory of the granting State on a service which originates or terminates in the home country of the foreign carrier or (in connection with the so-called Seventh Freedom of the Air) outside the territory of the granting State (also known as a Eighth Freedom Right or "consecutive cabotage").

Ninth Freedom of The Air - the right or privilege of transporting cabotage traffic of the granting State on a service performed entirely within the territory of the granting State (also known as a Ninth Freedom Right or "stand alone" cabotage).

另外也有所谓第九航权，是指上述第八航权分为连续的和非连续的两种，如果是“非连续的国内载运权”即为第九航权。值得留意的是第八航权和第九航权的区别，虽然两者都是关于在另外一个国家内运输客货，但是：第八航权所谓"cabotage"，只能是从自己国家的一条航线在别国的延长。但是第九航权，所谓的"full cabotage"，可以是完全在另外一个国家开设的航线。

例如Qantas在新西兰境内的运营点对点的……AKL-WLG，AKL-CHC之类，就是第九航权的例子。所谓"open sky"所给予的自由都是第九航权，而不仅仅是第八航权(cabotage)。

Source: Manual on the Regulation of International Air Transport (Doc 9626, Part 4)

请参考Wikipedia 英文版说明
http://en.wikipedia.org/wiki/Freedoms_of_the_air

为什么要在航班起飞前30分钟停办登机手续

2009-04-06T19:09:00.002+08:00

经常外出的人都知道，坐火车可以在火车发车前几分钟通过检票口进站上车，但为什么乘飞机要在航班起飞前30分钟办登机手续，大都所知甚少。

那么，为什么要规定在航班起飞前30分钟停止办理乘机手续呢？　

首先，要明确何谓起飞时间？根据民航有关规定，民航班期时刻表向旅客公布的起飞时间系指地面保障工作完毕，飞机关上客、货舱门的时间，而不是飞机离地升空的时间。　

其次，要知道停止办理乘机手续到关机门之间，机场工作人员有哪些工作要做？据了解，主要有以下工作要做：

一、是运输值机、配载人员要结算旅客人数、行李件数，结合货运装运情况计算飞机载重，画出平衡表及重心位置，做好舱单后送交机组签字；

二、是要将旅客托运的行李核对清楚后装运飞机；

三、是要对办完乘机手续的旅客进行安全检查；

四、是广播通知旅客到指定登机口检票，并引导旅客登机，如登机旅客须使用摆渡车运送，则耗时要长；

五、是清点机上旅客人数、与地面检票情况进行核对。

为什么飞机要用雷达操纵

2009-04-06T19:00:00.000+08:00

雷达在航空事业中的用途是十分广泛的。军用飞机场和大城市的民航机场是十分繁忙的。虽然机场很大，由于飞机速度很快，为了避免飞机碰撞，必须严格地控制飞机在机场上空的飞行以及起飞和着陆。为了完成这个任务，机场的调度人员就必须及时掌握远离机场几百公里和机场上空所有飞机的位置、速度和飞行方向，这样机场调度人员就可以向各架飞机发出先后起飞着陆的指示。

雷达是完成这一任务的最好工具。机场上装有雷达，机场调度人员就可以从雷达显示器上，清楚地看到机场上空几百公里范围之内的全部情况，而且不受天气情况的限制，进行空中交通的指挥工作。这种雷达一般叫做“空中交通管制雷达”和“精密着陆雷达”。
　　
飞机着陆大致可分两个阶段。第一个阶段叫做“引近”，这一阶段的任务，就是飞机进入机场临近上空准备着陆，飞机沿着机场跑道的延长线逐渐下降，直到离地面只有30米左右的地面；第二阶段叫做“拉平”，在这阶段，飞机逐渐改变上一阶段的下降角度，而按照一定的曲线飘飞着陆。

在飞机着陆的这两个阶段中，机场上装置的精密着陆雷达就要起作用了。在这种雷达的显示器上，预先显示出一条理想的飞机降落轨迹，通常叫做“下滑线”。在飞机着陆过程中，雷达连续地测量飞机的位置，观察飞机是否处在正确的飞行道上，并通过无线电话指挥驾驶员按照正确的下滑线飞行，直至降落在跑道上。
　　
不仅飞机的起飞和着陆要用雷达控制，而且飞机在飞行过程中也要用到雷达。飞机从一地飞往另一地是要按预先规定好的航线飞行的。如果是白天和晴天，领航员又熟悉飞行路线，可以不用雷达来保证飞机按航线飞行；如果是黑夜，或是云雾天气，或是领航员对航线不熟，那就要用雷达导航了。

在飞机上装一部雷达，天线朝向地面，这样在平面位置显示器上就显示出了一幅“雷达地图”，领航员随时观看这雷达地图，就能随时知道飞机的位置，保证飞机按航线飞行。有时领航员还要使用一种特殊的雷达图，这种特殊的雷达图，是把显示器显示出来的地形图的图片和实际地形图合并在一起而产生的，有了这个图，领航员就可以根据显示器显示的雷达地图，在他陌生的地带飞行，并保持正确的航线。
　　
飞行员在飞行过程中，必须随时掌握飞机距离地面的高度，在飞机上装一部叫做“雷达测高计”的测高雷达。这样，在海洋上空飞行，就能随时知道飞机距离海平面的高度；在大平原上空飞行，可以随时知道距离陆地的高度；在崇山峻岭上飞行，可以随时知道收音机距离高峰、山岭的高度。在一些需要低空突防的军用飞机上，还要装上一种“防撞雷达”，以保证飞机在低空高速飞行时，对高山和高大建筑物自动避让。

乘机安全常识

2009-04-06T18:58:00.001+08:00

随着社会的进步，我们的交通运输变得越来越发达，飞机变成了一种十分通用的交通工具，乘坐飞机旅行既省时，又舒适。

虽然飞机的事故发生率远远低于汽车、火车等交通工具，但由于飞机的特殊性，一旦发生事故就会造成较严重后果，而且民航史上也有着许多因旅客安全常识的缺乏而造成的惨痛教训，因此，普及人们的飞行安全常识就成了一件刻不容缓的事。　　

旅客在登机以前必须办理登机手续，同时接收安全检查，以确保你所携带的物品符合安全规定，以减少事故隐患。登上飞机以后，一定要在起飞和着陆前根据提示系好安全带，尽管现代旅客机远比汽车平稳得多，但在任何情况下都不要忽视安全。

由于飞机在起飞和着陆时处于颠簸的气流中，因此少数人可能会感到不适，有些人也会出现象晕车一样的晕机现象，有这种情况的旅客只要在登机前服用防晕药，同时注意减少活动即可。

此外，由于飞机高度的变化所引起的气压的变化可能会导致耳中不适，此时只要做吞咽动作，使耳腔内的气压平衡，就可以解除。旅客机上是严禁吸烟的，吸烟不但会污染空气，更为重要的是容易引发火灾，酿成重大事故。因此，对于那些习惯于上卫生间吸烟的人来说尤其需要注意，改掉这种不良习惯。　　

前面已经说道，乘坐飞机旅行是较为舒适，然而，飞行中的轻度颠簸和轻度缺氧对于某些有伤病旅客来说却是很危险的。那么，患有哪些疾病的人不宜乘坐飞机呢？

一般来说，这些病人包括未经控制的心力衰竭，发病后不到6周的心肌梗塞和7日内做过气胸照相术的人，发病后3个月的气胸病人，3周内作过胃肠手术的入，胃溃疡出血者，空洞型肺结核病人，血红蛋白量低于标准值50％或红细胞低于250万／立方毫米的贫血患者，伴有严重并发症的高血压病患者，严重哮喘、肺炎，支气管扩张，急性肺水肿等患者，脑梗塞，脑动脉硬化的患者。

此外，对于接近预产期的孕妇，在旅行时可能导致早产，而且在飞行中分娩是较危险的，因此怀孕超过8个月者，也不应乘座飞机。在此只是对不宜乘坐飞机的病人作了一个简单的介绍，关于这方面更详细的情况，可以咨询民航的有关规定。　　

一般来说，由于航空技术的发展及民航安全管理措施的加强，现代旅客机的事故率已经非常低了，即使发生故障也可以采取相应的安全措施将损失减少到最小。因此，万一事故发生时首先要保持冷静，在乘务员的指导下，有组织地采取安全救生行动。

在民航飞行事故中，曾经发生过这样的情况：因慌张所造成的伤亡比事故本身所造成的伤亡还大。比如在飞机迫降后撤离事故飞机时，一定要有秩序，拥挤反而会造成更大的伤害。

总之，民航飞行的安全问题不单是航空公司的事，每一位旅客都应该自觉遵守民航安全规定，培养自身的安全常识，共同杜绝事故的隐患。

飞行安全

2009-04-06T18:54:00.001+08:00

全球各大航空公司都把安全问题放在第一位，机上的安全保障系统也力求世界领先，与此同时，飞行安全也需乘客自身有安全意识，这样才能安全地到达我们心仪已久的旅行目的地。　　

安全保障系统　　

航空公司当然把安全问题放在第一位。例如在开发和采用机上安全保障系统方面居世界领先地位的英国航空公司。根据英航安全保障系统所提出的安全标准将在2005年以后被所有航空公司采纳。此外英航在英国拥有人数最多的飞机维修工程人员，他们每年要耗费很多时间来检修保养飞机，以确保乘客的安全。　　

乘客们在出游前除了选择安全可靠，服务品质优良的航空公司外。我们特向英国航空公司的相关专家请教了乘坐民航客机时乘客自身有哪些注意事项。　　

起飞前做好准备　　

坐下后首先别忘系上安全带，这会使你在飞机遇到气流时得到保护。与此同时，也应该立即关闭手机，以免干扰雷达系统影响飞机起飞。遭遇气流的情况会突然发生，即使在一般的飞行中也有可能造成严重伤害。注意听起飞前的安全注意须知，熟悉所有紧急出口的位置。　　

饮酒不能过量　　

飞行中避免饮酒过度。飞机客舱是加压的，饮酒会加剧这种感觉。记住，进入机场，完成所有登记手续，这一系列活动会使你有些脱水。脱水、飞行高度和酒精综合作用的后果是非常严重的。同样，别吃得太饱，否则在客舱这样一个人工环境里你很快就会觉得恶心。如果在假期中曾经潜水，要确保潜水后至少24小时内不要飞行。因为你仍然处在加压过程中，需要时间让体内的有害气体排出。　　

穿着天然织物　　

尽量穿着天然织物。因为万一碰上起火，合成纤维会融化，非常危险。而排气性能良好、宽松的天然纤维还能防止过热。长衣和长裤都是不错的选择，鞋子也要合脚并最好是天然材料做成的，避免穿高跟鞋，因为鞋跟会损坏应急坡道。在紧急撤离飞机时，放弃你的手提行李，事先把所有最重要的东西放在腰包中贴身带着。　　

熟悉应急措施　　

碰上紧急情况可以利用地板上的标志找到最近的紧急出口，行动要迅速。一次性面罩可以滤掉万一发生火灾时散发的有毒气体。如果万一飞机迫降在了海上，你必须知道救生衣放在哪里以及在何时、应如何使用；明确救生筏在什么位置；另外漂浮坐垫或空的、密闭的瓶子等，都能对水面救助有所帮助。　

风切变 Wind shear

2009-04-06T16:13:00.002+08:00

高空水平风切产生的云层现象

风切变是一种大气现象，是风速在水平和垂直方向的突然变化。由于速度是矢量，有大小有方向，所以风切变包括水平风的垂直切变，水平风的水平切变以及垂直风的切变。

风切变是导致飞行事故的大敌，特别是低空风切变。国际航空界公认低空风切变是飞机起飞和着陆阶段的一个重要危险因素。　　

为什么低空风切变会有如此的危害性呢？这是由风切变的本身特性造成的。以危害性最大的微下冲气流为例，它是以垂直风切变为主要特征的综合风切变区。

由于在水平方向垂直运动的气流存在很大的速度梯度，也就是说垂直运动的风速会出现突然的加剧，就产生了特别强的下降气流，被称为微下冲气流。

垂直风切对飞机降落时的影响

这个强烈的下降气流存在一个有限的区域内，并且与地面撞击后转向与地面平行而变成为水平风，风向以撞击点为圆心四面发散，所以在一个更大一些的区域内，又形成了水平风切变。如果飞机在起飞和降落阶段进入这个区域，就有可能造成失事。

比如，当飞机着陆时，下滑通道正好通过微下冲气流，那么飞机会突然的非正常下降，偏离原有的下滑轨迹，有可能高度过低造成危险。当飞机飞出微下冲气流后，又进入了顺风气流，使飞机与气流的相对速度突然降低，由于飞机在着陆过程中本来就在不断减速，我们知道飞机的飞行速度必须大于最小速度才能不失速，突然的减速就很可能使飞机进入失速状态，飞行姿态不可控，而在如此低的高度和速度下，根本不可能留给飞行员空间和时间来恢复控制，从而造成飞行事故。　
　

垂直风切对飞机降落时的影响

据统计，风切变飞行事故都发生在300米以下的起飞和着陆飞行阶段，尤其以着陆阶段为甚。占78％。风切变说到底是一个飞机能量管理问题。如当遇到使飞机性能降低的风切变时，飞机如具有机动的能量能加速以克服风切变而改出，就可以转危为安。

若飞行高度很低，机动能量余量不足，飞机抗拒不了突然袭来的风切变，则只能失速掉高度以致坠机。反之，飞行高度较高，飞机机动能量余量较大，则往往不易发生不可抗拒的机毁人亡事故。　　

由于风切变现象具有时间短、尺度小、强度大的特点，从而带来了探测难、预报难、航管难、飞行难等一系列困难，是一个不易解决的航空气象难题。因此，目前对付风切变得最好办法就是避开它。因为某些强风切变是现有飞机的性能所不能抗拒的。

进行风切变的飞行员培训和飞行操作程序设置，在机场安装风切变探测和报警系统，以及机载风切变探测、告警、回避系统，都是目前减轻和避免风切变危害的主要途径。

关于飞机机翼（三）

2009-04-06T10:37:00.001+08:00

机翼的各部分装置介绍
　
副翼(Aileron):　副翼是指安装在机翼翼梢后缘外侧的一小块可动的翼面。为飞机的主操作舵面，飞行员操纵左右副翼差动偏转所产生的滚转力矩可以使飞机做横滚机动。翼展长而翼弦短。副翼的翼展一般约占整个机翼翼展的1/6到1/5左右，其翼弦占整个机翼弦长的1/5到1/4左右。飞行员向左压驾驶盘，左边副翼上偏，右边副翼下偏，飞机向左滚转；反之，向右压驾驶盘右副翼上偏，左副翼下偏，飞机向右滚转。
　
前缘缝翼（Leading Edge Slat):前缘缝翼是安装在基本机翼前缘的一段或者几段狭长小翼，主要是靠增大飞机临界迎角来获得升力增加的一种增升装置。

前缘缝翼的作用主要有两个：一是延缓机翼上的气流分离，提高了飞机的临界迎角，使得飞机在更大的迎角下才会发生失速；二是增大机翼的升力系数。其中增大临界迎角的作用是主要的。这种装置在大迎角下，特别是接近或超过基本机翼的临界迎角时才使用，因为只有在这种情况下，机翼上才会产生气流分离。

现代客机的前缘缝翼没有专门的操纵装置，一般随襟翼的动作而随动，在飞机即将进入失速状态时，前缘缝翼的自动功能也会根据迎角的变化而自动开关。

在前缘缝翼闭合时（即相当于没有安装前缘缝翼），随着迎角的增大，机翼上表面的分离区逐渐向前移，当迎角增大到临界迎角时，机翼的升力系数急剧下降，机翼失速。当前缘缝翼打开时，它与基本机翼前缘表面形成一道缝隙，下翼面压强较高的气流通过这道缝隙得到加速而流向上翼面，增大了上翼面附面层中气流的速度，降低了压强，消除了这里的分离旋涡，从而延缓了气流分离，避免了大迎角下的失速，使得升力系数提高。

附：关于失速
机翼能够产生升力是因为机翼上下存在着压力差。但是这是有前提条件的，就是要保证上翼面的的气流不分离。如果机翼的迎角大到了一定程度，机翼相当于在气流中竖起的平板，由于角度太大，绕过上翼面的气流流线无法连贯，会发生分离，同时受外层气流的带动，向后下方流动，最后就会卷成一个封闭的涡流，叫做分离涡。像这样旋转的涡中的压力是不变的，它的压力等于涡上方的气流的压力。所以此时上下翼面的压力差值会小很多，这样机翼的升力就比原来减小了。到一定程度就形成失速，对应的机翼迎角叫做失速迎角或临界迎角。
　
襟翼（Flap）：
襟翼是安装在机翼后缘内侧的翼面，襟翼可以绕轴向后下方偏转，主要是靠增大机翼的弯度来获得升力增加的一种增升装置。当飞机在起飞时，襟翼伸出的角度较小，主要起到增加升力的作用，可以加速飞机的起飞，缩短飞机在地面的滑跑距离；当飞机在降落时，襟翼伸出的角度较大，可以使飞机的升力和阻力同时增大，以利于降低着陆速度，缩短滑跑距离。

在现代飞机设计中，当襟翼的位置移到机翼的前缘，就变成了前缘襟翼。前缘襟翼也可以看作是可偏转的前缘。在大迎角下，它向下偏转，使前缘与来流之间的角度减小，气流沿上翼面的流动比较光滑，避免发生局部气流分离，同时也可增大翼型的弯度。

前缘襟翼与后缘襟翼配合使用可进一步提高增升效果。一般的后缘襟翼有一个缺点，就是当它向下偏转时，虽然能够增大上翼面气流的流速，从而增大升力系数，但同时也使得机翼前缘处气流的局部迎角增大，当飞机以大迎角飞行时，容易导致机翼前缘上部发生局部的气流分离，使飞机的性能变坏。如果此时采用前缘襟翼，不但可以消除机翼前缘上部的局部气流分离，改善后缘襟翼的增升效果，而且其本身也具有增升作用。

B737-600的双开缝后缘襟翼

克鲁格襟翼（Krueger Flap)：与前缘襟翼作用相同的还有一种克鲁格襟翼。它一般位于机翼前缘根部，靠作动筒收放。打开时，伸向机翼下前方，既增大机翼面积，又增大翼型弯度，具有较好的增升效果，同时构造也比较简单。

左图为波音777的驾驶舱中央操纵台部分，民航飞机的机翼各翼面的操作一般类似。
如本文前述，前缘缝翼没有专门的操纵装置，副翼的作动是依靠驾驶盘的左右转动。而襟翼、扰流板的操纵就在驾驶舱中央操纵台的油门杆两侧

扰流板（Spoiler）：
有的称之为“减速板”、“阻流板”或“减升板”等，这些名称反映了它们的功能。分为飞行、地面扰流板两种，左右对称分布，地面扰流板只能在地面才可打开，实际上扰流板是铰接在机翼上表面的一些液压致动板，飞行员操纵时可以使这些板向上翻起，增加机翼的阻力，减少升力，阻碍气流的流动达到减速、控制飞机姿态的作用。

Airbus A319落地后减速板打开
在空中飞行时，扰流板可以降低飞行速度并降低高度。只有一侧的扰流板动作时，作用相当于副翼，主要是协助副翼等主操作舵面来有效控制飞机做横滚机动在飞机着陆在地面滑跑过程中时，飞行、地面扰流板会尽可能地张开，以确保飞机迅速减速。

关于飞机机翼（二）

2009-04-06T10:32:00.002+08:00

机翼在使飞机升空飞行中的重要作用

飞机在飞行过程中受到四种作用力：
升力----由机翼产生的向上作用力
重力----与升力相反的向下作用力，由飞机及其运载的人员、货物、设备的重量产生
推力----由发动机产生的向前作用力
阻力----由空气阻力产生的向后作用力，能使飞机减速。

由此可见，机翼的主要功用就是产生升力，以支持飞机在空中飞行。它为什么能产生升力呢？

首先要从飞机机翼具有独特的剖面说起，前面名词解释已提到，机翼横断面（横向剖面）的形状称为翼型，机翼剖面的集合特性与机翼的空气动力有密切的关系。从侧面看，机翼顶部弯曲，而底部相对较平。机翼在空气中穿过将气流分隔开来。一部分空气从机翼上方流过，另一部分从下方流过。

机翼产生升力的原因

空气的流动在日常生活中是看不见的，但低速气流的流动却与水流有较大的相似性。日常的生活经验告诉我们，当水流以一个相对稳定的流量流过河床时，在河面较宽的地方流速慢，在河面较窄的地方流速快。流过机翼的气流与河床中的流水类似，由于机翼一般是不对称的，上表面比较凸，而下表面比较平，流过机翼上表面的气流就类似于较窄地方的流水，流速较快，而流过机翼下表面的气流正好相反，类似于较宽地方的流水，流速较上表面的气流慢。

根据流体力学的基本原理，流动慢的大气压强较大，而流动快的大气压强较小，这样机翼下表面的压强就比上表面的压强高，换一句话说，就是大气施加与机翼下表面的压力(方向向上)比施加于机翼上表面的压力(方向向下)大，二者的压力差便形成了飞机的升力。

简单来说，飞机向前飞行得越快，机翼产生的气动升力也就越大。当升力大于重力时，飞机就可以向上爬升；当升力小于重力时，飞机就可以降低高度。
　　
当飞机的机翼为对称形状，气流沿着机翼对称轴流动时，由于机翼两个表面的形状一样，因而气流速度一样，所产生的压力也一样，此时机翼不产生升力。

但是当对称机翼以一定的倾斜角（称为攻角或迎角）在空气中运动时，就会出现与非对称机翼类似的流动现象，使得上下表面的压力不一致，从而也会产生升力。
　

关于飞机机翼 (一）

2009-04-06T10:29:00.001+08:00

机翼的基本概念

机翼的主要功用是产生升力，以支持飞机在空中飞行；同时也起一定的稳定和操纵作用。是飞机必不可少的部件，在机翼上一般安装有飞机的主操作舵面：副翼，还有辅助操纵机构襟翼、缝翼等。另外，机翼上还可安装发动机、起落架等飞机设备，机翼的主要内部空间经密封后，作为存储燃油的油箱之用。

相关名词解释：

翼型：飞机机翼具有独特的剖面，其横断面（横向剖面）的形状称为翼型，称为翼型

前缘：翼型最前面的一点。

后缘：翼型最后面的一点。

翼弦：前缘与后缘的连线。

弦长：前后缘的距离称为弦长。如果机翼平面形状不是长方形，一般在参数计算时采用制造商指定位置的弦长或平均弦长

迎角(Angle of attack) ：机翼的前进方向(相当与气流的方向)和翼弦(与机身轴线不同)的夹角叫迎角，也称为攻角，它是确定机翼在气流中姿态的基准。

翼展：飞机机翼左右翼尖间的直线距离。

展弦比：机翼的翼展与弦长之比值。用以表现机翼相对的展张程度。

上（下）反角：机翼装在机身上的角度，即机翼与水平面所成的角度。从机头沿飞机纵轴向后看，两侧机翼翼尖向上翘的角度。同理，向下垂时的角度就叫下反角。

上（中、下）单翼：目前大型民航飞机都是单翼机，根据机翼安装在机身上的部位把飞机分为上（中、下）单翼飞机也有称作高、中、低单翼。机翼安装在机身上部（背部）为上单翼；机翼安装在机身中部的为中单翼，机翼安装在机身下部（腹部）为下单翼。

上单翼的飞机一般为运输机与水上飞机，由于高度问题，此时起落架等装置一般就不安装在机翼上，而改在机身上，使用上单翼的飞机一般采用下反角的安装。

中单翼因翼梁与机身难以协调，几乎只存在理论上；

下单翼的飞机是目前民航飞机常见的类型，由于离地面近，便于安装起落架，进行维护工作，使用下单翼的飞机一般采用上反角的安装。
　

海里 Nautical mile

2009-04-06T10:00:00.001+08:00

海里，是一个用于航海或航空的长度单位，通常相等于国际单位制1,852米。没有统一符号，通常为nm（也可以是纳米），NM和nmi。《中华人民共和国法定计量单位》所用的符号是n mile。

“海里”传统上定义为围绕地球一圈的一角分（一圈等于360度，1度等于60分，故1海里的长度是子午线长度两倍÷360÷60）。

它可从航海图中，以子午线上的纬度的改变来量度。由于地球并非标准球体，1度的距离并不完全相当，因此海里的长度并不固定。

1929年在摩纳哥的International Extraordinary Hydrographic Conference，定义了1海里为1,852米。在此之前，不同国家、地区对1海里的定義稍有不同，如英国在1970年前的1海里为6,080英尺，相当于1,853.184米，而美国以前1海里为6,080.2英尺，相当于1,853.249米。

換算

1海浬的距離即:
1852 米
1.852 公里
1.150 779 英里
6,076.115 5 英尺

傳統:
3 海浬 = 1 海列（sea league）
60 海浬 = 1 度（360 度 = 1 圓周）

能見度

2009-04-06T09:40:00.004+08:00

能見度又稱可見度，指觀察者離物體多遠時仍然可以清楚看見該物體。

氣象學中，能見度被定義為大氣的透明度，因此在氣象學裏，同一空氣的能見度在白天和晚上是一樣的。

能見度的單位一般為米或公里，天氣好的時候能見度高，數值大；天氣不好時能見度低，數值小。

低能見度多出現於雨天、大霧時及有煙霞的日子。

空氣污染會嚴重降低能見度，因此不少地區以能見度為空氣污染的指標之一。

能見度對於航空、航海和陸上運輸都非常重要。

中英文飞机维修部品

2009-04-06T03:37:00.004+08:00

单向活门 One-Way Valve
快速热水器 Rapid Water Heater
安全活门 Safety valve
高压级调节活门 High stage pilot
高压级引气活门 High stage regulator
引气调节器 Bleed air regulator
反流检查控制活门 Reverse Flow Check Control Valve
过滤型压差调节器 Filter type differential pressure regulator
四英寸直径气动蝶形关断活门 Four inch diameter pneumatic butterfly shutoff valve
马桶组件 Toilet assembly
冲洗活门组件 Flush Valve Assy
圆顶灯 Dome Light
真空马桶组件 Vacuum toilet assemblies
活门组件 Valve Assy
冲水马桶组件 Flushing toilet assembly
排水活门组件 Holders of drain valve assembly
控制显示组件 Control/Display Unit
飞行管理计算机 Flight Management Computer
防冰活门 Nose cowl thermal anti-ice valve
液晶控制显示组件 Liquid Crystal DisplayControl/Display Unit
热交换器 Heat exchanger
初级热交换器　Primary heat exchanger
货舱动力驱动组件 Cargo Powered Drive Unit
发动机仪表系统次显示板 E.I.S secondary display panel
58加仑真空污水箱 58 Gallon vaccum waste tanks
50A 不可调变压整流器 Transformer-Rectifier,50 AMP Unregulated
直流转接盒 DC Junction Box
风档温度控制器 Windshield Temperature Controller
窗户和空速管加热模件组件P5-9 Window and Pitot Heat Module Assembly P5-9
燃油控制模件组件P5-2 Fule control module assy p5-2
电源管理控制模件组件P5-68 Power management control module assy.
交流系统发电机/APU模件组件P5-4 AC System Generator/APU ModuleP5-4 Assembly
发电机驱动和备用电源模件组件P5-5 Generator Drive and Standby Power Module Assembly P5-5
发电机驱动和备用电源模件组件P5-6 Generator Drive and Standby Power Module AssemblyP5-6
发电机驱动和备用电源模件组件P5-7 Generator Drive and Standby Power Module Assembly,
P5-7
飞行记录和马赫空速警告模件组件P5-19 Flight Recorder and Mach Airspeed Warning Module Assyembly P5-19
飞行控制模件组件P5-3 Flignt Control Module Assembly P5-3
烤箱 Oven
俯仰计算机 Pitch Computer
变压整流组件 Transformer Rectifier Unit
发动机附加组件 Engine Accessory Unit Assembly
仪表着陆控制板组件 ILS Control Panel Assy.
特高频全向导航控制板组件 VOR Control Panel Assy.
机翼位置航行灯 Wing Position Navigation Light
飞机航行防撞频闪灯 Aircraft Navigational，'Anti-collision Strobe Light
高亮度飞机识别灯 High Intensity Aircraft Recognition Light
飞机尾翼闪光灯 Aircraft Tail Position Light，Flashtube
飞机后位置航行灯 Aircraft Navigational Light-rear position
后位置灯组件 Rear Position Light Assembly
上机身防撞灯 Upper Fuselage Anti-Collision Light
下机身防撞灯 Lower Fuselage Anti-Collision Light
发动机仪表系统主显示板 E.I.S Primary Display Panel
马达泵过滤器组件 Motor-pump-filter unit assembly
压力调节活门 Pneumatic Pressure Regulating Valve
压力调节和关断活门 Pressure regulating and shutoff valve
高压级引气调节器 High stage valve双效用活门 Dual purpose valve
机头罩防冰活门 Nose Cowl Anti-lce Valve
预冷器冷却空气调节活门 Four inch diameter precooler control valve
预冷器冷却空气调节门 Modulating pre-cooler air valve
第十四级调节活门 Fourteenth stage pilot
驾驶舱灯 Cockpit Light
压差调节器 One and One-half inch diameter turbofan control shutoff differential pressure regulator
流量活门 Flow control valve
5英寸直径流量控制活门 Five inch diameter flow control valve
流量控制和关断活门 Flow control and shuttoff valve
3 1/2英寸直径流量控制活门 Three and one half inch diamter flow control valve
3 1/2英寸直径电动控制双向调节和关断蝶形活门 Three and one half inch diamter flow control valve electric dual modulating and shutoff butterfly valve
电瓶充电器 Battery Charger
偏航阻尼耦合器 Yaw Damper Coupler
大气数据计算机 Air Data Computer
天花板灯 Ceiling Light
飞行控制计算机 Flight Control Computer
方式控制板 Mode Control Panel
行李箱扭矩臂组件 Center Overhead Stowage Bin Upper Arm Torque Tube Assembly
防滞/自动刹车控制组件 AntiSkid/Autobrake Control Unit
防滞刹车控制组件 Skid Control Unit
刹车系统控制组件 Brake System Control Unit
着陆灯 Landing Light
收放着陆灯 Retractable Landing Light
回收箱挡块组件 Retractable Container Stop Assembly
发动机火警,过热,'APU火
警控制模件 Control Module,Engine Fire,Overheat & APU Fire
翼尖航行灯 Wing Tip Navigation Light
频闪灯电源 Strobe Power Supply
水壶 Water Boiler
组件/区域温度控制器 Pack/Zone Temperture Controller
客仓区域温度控制器 Cabin Zone Temperature Controller
组件温度控制器 Pack Temperature Controller
马达驱动风扇 Motor Driven Fan
座舱空气循环风扇 Cabin air recirculation fan
信号灯组件 Indicator Light AssemblyAPU
控制组件M820 APU Control Aassembly M280APU
控制组件 APU Control Unit Assembly
空调辅助组件 M324 Air Conditioning Accessory Unit Assembly M324
综合飞行系统辅助组件 Integrated Fight System Accessory UMA
轴流式风扇组件 Vaneaxial Fan Assembly
发动机振动监控器 Engine Vibraction Monitor
马达操纵关断活门 Motor Operated Air Shutoff Valve
发动机和APU火警控制模件组件P8-1 Engine and APU Fire Control Module Assembly P8-1
液压泵模件组件P5-8 Hydraulic Pumps Module Assembly P5-8
空调模件组件 Air Conditioning Module Assembly
发动机及机翼防冰模件组件 P5-11 Engine and Wing Anti-ice Module Assembly.P5-11
客舱温度模件组件P5-17 Cabin Temperature Module AssemblyP5-17
燃油系统模件组件P5-2 Fuel System Module Assembly P5-2
窗户及全-静压空速管加热模件 P5-9 Window and Combind Pitot-Static Heat Module Assembly P5-9
窗户及全-静压空速管加热模件 Window and Combind Pitot-Static Heat Module Assembly P5-9IRS
方式选择模件组件 IRS Mode Selector Module Assembly
压力控制板 Pressure Control Panel
快速烤箱DF700LH High Speed Oven DF 700LH
蒸汽烤箱 Steam Oven
高速烤箱 High Speed OvenDR4100
系列热水器 Water Heater DR4100 Series
活门 High Stage Bleed Valve
汇流条电源控制组件 Bus Power Control Unit
流量控制活门 Flow Control Valve
自动油门计算机 Autothrottle Computer
压力控制器 Pressure Controller
流量和关断活门 Flow control and shutoff valve
高压控制器 High Pressure Controller
真空抽气马桶 Vacuum toilet assembly
滑油箱 Lubricating oil tank
接近电门电子组件 Proximity Switch Electronics Unit
高压关断活门 High Pressure Shutoff Valve
咖啡壶组件 Coffeemaker Assembly
蒸气烤箱 Steam Oven
风档加温控制器 Window Heat Controller
凤挡加热控制组件 Window Heat Control Unit
烤箱组件 Oven Aseemblies
发动机超温火警探测器 Engine Overheat and Fire Detection Unit
麦克风 Micophone
发电机控制组件 Generator Control Unit
汇流条保护板 Bus Protection Panel
风扇活门 Fan Air Valve
高压流量控制活门 High Pressure Bleed Control Valve
清水箱 Potable Water Tank
数字/模拟转接器 Digital/Analog Adapter
串行摆动飞机航行灯 Tandem Oscillating Aircraft Navigational Light
数字式大气数据计算机 Digital Air Data Computer
马桶真空泵 Vacuum Generator
飞机头戴式耳机 Aircraft Headsets
自动关闭水开关组件 Fancet Assy-self close
放音机 Wall Mount Type Prerecorded
固态壁挂式预录通告和登机音乐磁带放音机 SOLID-STATE WALL MOUNT PRAM

民航专业术语解释

2009-04-06T03:26:00.003+08:00

内容介绍的是经常在民航相关新闻、文章中出现的一些常用专业用语、参数、缩略语的基本含义。

复飞：GA（Go Around）：由于机场障碍或飞机本身发生故障（常见的是起落架放不下来），以及其他不宜降落的条件存在时，飞机中止着陆重新拉起转入爬升的过程，称为复飞。飞机在着陆前有一个决断高度，在飞机下降到这一高度时，仍不具备着陆条件时，就应加大油门复飞，然后再次进行着陆，这一过程同起飞、着陆的全过程是一样的，一般经过一转弯、二转弯、三转弯、四转弯，然后对准跑道延长线再次着陆。如果着陆条件仍不具备，则可能再次复飞或飞到备用机场降落。需要明确指出的是，复飞并不可怕，按程序进行复飞不会有任何危险，民航飞机降落前都预先设定了复飞程序，自动化程度高，这是一个很基本的飞行操作程序。

备降：当飞机不能或不宜飞往预定着陆机场或在该机场着陆时，而降落在其他机场，就称为备降。发生备降的原因很多，主要有航路交通管制、天气状况不佳、预定着陆机场不接收、天气状况差、飞机发生故障等等。

备降机场：Alternate airport当飞机不能或不宜飞往预定着陆机场或在该机场着陆时可以飞往的另一个机场。备降机场包括起飞备降机场、航路备降机场和目的地备降机场。备降机场一般在起飞前都已预先选定好，只有发生某些特殊或紧急情况才会临时选择非计划中的备降机场降落。

可控飞行撞地：CFIT（Controlled flight into terrain）在机组操纵原因造成的飞行事故中有一种叫做"可操纵的飞机撞地事故"，即CFIT，就是在飞行中并不是由于飞机本身的故障，或发动机失效等原因发生的事故，而是由于机组在毫无觉察危险的情况下，操纵飞机撞山、撞地或飞入水中，而造成飞机坠毁或严重损坏和人员伤亡的事故。这类CFIT事故在整个飞行事故中的比例也是比较大的，据国外统计的资料，客机死亡人数约80％是由CFIT造成的。

缩小垂直间隔：RVSM（Reduced Vertical Separation Minimum）即将现代喷气式民航客机巡航阶段所在用的飞行高度层FL290至FL410（含）之间的垂直间隔标准由2000英尺缩小到1000英尺，从而增加空域容量，提高航空公司的运行效益，减轻空中交通管制指挥的工作负荷。国际民航组织（ICAO）从70年代开始研究缩小垂直间隔标准的问题。2002年1月，经有关国家民航当局和相关国际民航组织共同商讨，经过共达13次的工作会议，决定从2002年2月21日起在南中国海地区实施RVSM运行。未获得RVSM运行批准的航空器将不得在RVSM空域内运行，而只能在飞行高度层FL290以下飞行。

能见度：VIS(Visibility)是反映大气透明度的一个指标，航空界定义为具有正常视力的人在当时的天气条件下还能够看清楚目标轮廓的最大距离。能见度和当时的天气情况密切相关。当出现降雨、雾、霾、沙尘暴等天气过程时，大气透明度较低，因此能见度较差。测量大气能见度一般可用目测的方法，也可以使用大气透射仪、激光能见度自动测量仪等测量仪器测量。

跑道视程：RVR (Runway Visual Range)在跑道中心线位置，驾驶员能看到跑道表面的标示或是跑道灯或中心线灯的距离。当机场地面能见度较差时由航空管制应向运行中航空器分段报告跑道视程数值包括接地段、中间段和滑离段的RVR数值。

空地数据链系统（飞机通信寻址和报告系统）:ACARS(Aircraft Communication Addressing and Reporting System) ACARS是一个基于VHF（甚高频）的双向机载数据通信系统，为航空公司空地、地地大流量数据通信提供服务，实现各种信息的交换。一方面，它可以使飞行的飞机在无须机组成员干预的情况下自动向航空公司地面应用系统提供飞行动态、发动机参数等实时数据信息，同时也可以向地面传送其他各类信息，使航空公司运行控制中心在自己的应用系统上获得飞机的实时的、不间断的大量飞行数据及相关信息，及时掌握本公司飞机的动态，实现对飞机的实时监控，满足航务、运营、机务等各相关部门管理的需要；另一方面，地面可向空中飞行的飞机提供气象情报、航路情况、空中紧急故障排故措施等多种服务，提高飞行安全保障能力及对旅客的服务水平。在常用的VHF地空通信频道日益饱和，信息传送量少、速度慢的状况下，这种双向的数据通信系统可显著地改善和提高地面、空中通信保障能力。目前，中国民航的空地数据链系统是一种面向字符型的数据链，不能传输数字语音和数据流文件，如气象云图等。

运行控制中心：（AOC：Airplane Operating Control）AOC是是航空公司的指挥核心，保证航空公司运行安全的中枢，一种较为先进的运行生产管理模式。航空公司生产运作过去多是以调度为中心的运行生产管理模式，采用电传联系、手工记录和电话通知等手工操作模式，不仅速度慢，准确性也难以保证。AOC的建立则可以改善这些不足之处，AOC实现航空公司的资源整合，各分子公司、各类业务信息都集中到AOC系统，包括飞行签派、机务维修、地面保障、机组调配、载重平衡、食品配餐、物流运送等等，以此实现对内部的信息整合，对运行航班的统一调度指挥和集中管理，使生产运作流程更加合理、有效，提高整体运行效率。

决断高度(DA)/决断高(DH)：Decision Altitude/ Decision Height在精密进近中，如不能建立继续进近所必需的目视参考，则应当开始复飞的特定高度或高。

最低下降高度(MDA)/最低下降高(MDH)：在非精密进近或盘旋进近中，如不能建立必需的目视参考，则不能继续下降的特定高度或高。

航站自动情报服务广播:ATIS(Automatic Terminal Information System)在一些较繁忙航站，由空中交通管制单位负责向在本航站区域内运行中的航空器提供情报服务的手段，是一个依靠甚高频的广播系统，不间断的播放重要的数据，主要包括的内容有识别信息：机场名称、当前通播的观测时间、代号进近指示：预计使用跑道和进近方式、高度表拨正值、过渡高度层天气状况：大气温度、露点（当气温下降到露点以下是，空气中的水汽就会结成液态水滴，形成雾）、地面风向风速、能见度，跑道视程其他必要的运行情报：ATIS情报通播是按字母顺序依次排列的，一般为每小时换一次，有重大变化时将进行及时更新，飞行员在与进离场管制单位建立首次联系时，应该确认已收到通播。由于ATIS存在提供信息量较少、不及时、效率不高等不足之处，目前民航正在研究利用ACARS系统提供D-ATIS（数据链飞行情报服务）。　

快速存取记录器:QAR(Quick Access Recorder) 用于监控、记录大量飞行参数、数据的机载设备。其记录容量一般为128MB，连续记录时间可达600小时，可以同时采集数百个数据，涵盖了飞机运行品质的绝大部分参数。QAR监控是保障飞行安全，提高运营效率的一项科学而有效的技术手段，其监控结果是飞行技术检查、安全评估、安全事件调查和维护飞机的重要依据。在QAR的帮助下，航空公司能够及时发现飞行中机组操纵、发动机工作状况以及航空器性能等方面存在的问题，分析查找原因，掌握安全动态，采取针对性措施，从而消除事故隐患，确保飞行安全。目前，绝大部分的民航飞机均加装了这类先进的监控设备。

代号共享:最基本的概念是，旅客在全程旅行中有一段航程或全程航程是乘坐出票航空公司航班号但非出票航空公司承运的航班的。代号共享则可以使航空公司利用合作伙伴现成的航线、飞机，绕过国家间市场准入的限制，使自身的航线结构快速全球化。利用代号共享的安排，航空公司可能既满足了航线扩张的需要，又不用投入巨额资金，也可使航空公司在不增加新的运力的情况下，增加航班班次，提高航线质量，降低单位营运成本，提高市场占有率并使原有的竞争对手变成合作伙伴，优化经营环境。代码共享的种类有：1.完全代号共享，指共享航空公司和承运航空公司用各自的航班号共同销售同一航班，而不限制各自的座位数。2.包座代号共享指共享航空公司和承运航空公司达成合作协议，购买承运航空公司某一航班的固定座位数，共享航空公司只能在此范围内用自己的航班号进行销售。

轮挡时间与轮挡油耗:滑行飞机在地面停放后，在机轮下都放置轮挡，防止飞机运动，当飞机启动发动机准备运动时，地面人员撤去轮挡。从这个时候起计算飞机的运行时间，称为轮挡时间，计算的耗油量称为轮挡油耗。　

八该一反对:该复飞的复飞、该穿云的穿云、该返航的返航、该备降的备降、该绕飞的绕飞、该等待的等待、该提醒的提醒、该动手的动手；反对盲目蛮干“八该一反对”是保证飞行安全实践的经验总结，是贯彻落实飞行规则和有关规定，正确处理飞行中遇到的各种情况的通常概括。

起飞距离：从飞机滑跑开始到飞越35米高度的地面距离称为起飞距离，飞机起飞距离越短越好。

着陆距离:从飞机最后进近到50英尺高度开始到飞机完全停止在跑道上的距离称为着陆距离,当然,飞机着陆距离也是越短越好。

发动机冷转： 发动机冷转就是用起动机驱动使整个发动机转子旋转，此过程中发动机不供油，不点火，发动机是靠起动机进行被动旋转，一般进行发动机冷转程序出现在发动机起动失败后，此时进行冷转的目的主要是吹掉由于起动失败在发动机中的积油，防止再次起动点火时出现意外，同时，进行冷转也可降低发动机的温度，防止再次起动时超温。

内置测试设备:BITE( Built in Test Equipment) 从航空电子领域发展起来的一种设备内部测试技术，随着计算机技术和大规模集成电路的广泛应用，先进设备、系统在改善和提高性能的同时，也大大增加了设备的复杂性，这对设备的维修性、可靠性和可用性有很大影响。拥有良好测试性的系统和设备BITE后，就可以及时、快速地检测与隔离该设备的故障，提高其可靠性与安全性，缩短故障检测与维修时间，提高系统可用性。

最低设备清单： MEL （Minimum Equipment List）

主最低设备清单： MMEL （Master Minimum Equipment List）MMEL是由航空器制造国的民航当局、适航机构制订的，用于指导航空器用户、航空公司具体编写MEL的纲领性文件，它规定了该型号飞机允许带有哪些不工作的仪表和设备放行，并对工作仪表设备的最低放行数量以及保留故障放行的限制条款作出了原则上的要求。

最低设备清单是由航空器营运人制定，经过本国适航机构批准的重要技术文件，MEL制定的依据是主最低设备清单 MMEL。MEL是在其基础上，根据本航空公司所选飞机构型上的不同，并结合本公司运行水平、经验等差异性，对特定型号并带有序号和注册号的航空器制定的在一定期限内可以允许不工作设备和系统的文件。

MEL应当遵守相应航空器型号的MMEL，或比其更为严格。MEL的主要用途就是充分利用飞机设计的安全余度，在保证运行安全的前提下在规定的期限内允许保留故障继续飞行，合理运用MEL可有效提高飞机的利用率和航班正点率，降低运营成本。值得注意的是，MEL不是航空器的维护标准，决不是提倡带故障飞行，维修部门应尽早完成排故工作。

民航专业缩略语

2009-04-06T03:21:00.004+08:00

ADIRS Air Data/Inertial Reference System 大气资料惯性基准系统
ADIRU Air Data/Inertial Reference Unit 大气资料惯性基准组件
AOA Angle―of―Attack 迎角
APPR Approach 进近
ARINC Aeronautical Radio Incorporated 航空无线电公司
ARM Aircraft Recovery Manual 飞机恢复手册
ARMD Armed 预位
ASCII American Standard Code for Information Interchange 美国信息互换标准代码
ATA Air Transport Association of America 美国航空运输协会
AVAIL Available 可用的，可实现的
C/B Circuit Breaker 电路跳开关
C/L Check List 检查单
CDU Control and Display Unit 控制显示组件
CVR Cockpit Voice Recorder 驾驶舱话音记录器
DDRMI Digital Distance and Radio Magnetic Indicator 数字式距离和无线电磁指示器
DEC Declination、Decrease 倾斜，偏角，偏斜、减少
DFDR Digital Flight Data Recorder 数字式飞行资料记录器
DISC Disconnect，Disconnected 脱开，脱开的
ETA Estimated Time of Arrival 预计到达时间
FADEC Full Authority Digital Engine Control 发动机全权限数字控制
FAIL Failed ，Failure 失效
FFS Full Flight Simulator 全动模拟机
ISOL Isolation 隔离
LRRA Low Range Radio Altimeter 低高度无线电高度表
LRU Line Replaceable Unit 航线可更换件
MSG Message 信息
NAS Navy and Army Standard 海军和陆军标准
N/A Not Applicable 不适用
NCD No Computed Data 无计算资料
OVBD Overboard 机外
OVHD Overhead 头顶的
OVHT Overheat 过热
OVLD Overload 过载
OVRD Override 超控
OVSP Overspeed 超速
OXY Oxygen 氧气
PSI Pound Per Square Inch 磅/平方英寸
PWR Power 动力，电源
QAD Quick-Attach-Detach 快速装卸
QFE Field Elevation Atmospheric Pressure 场压
QNE Sea Level Standard Atmosphere Pressure 海平面标准气压
QNH Sea Level Atmospheric Pressure 海平面气压
RA Resolution Advisory 决断提示
RMI Radio Magnetic Indicator 无线电磁指示器
SID Standard Instrument Departure 标准仪表离港
STAR Standard Terminal Arrival Route 标准进港航路
UTC Universal Time Coordinated 国际协调时
V1 Critical Engine Failure Speed 关键发动机失效速度
V2 Takeoff Safety Speed 起飞安全速度
V3 Flap Retraction Speed 襟翼收起速度
V4 Slat Retraction Speed 缝翼收起速度
WPT Waypoint 航路点
WXR Weather Radar 气象雷达
XPDR Transponder 应答机

民航常用基本缩略语

2009-04-06T03:17:00.002+08:00

ALT：Altitude 高度
ALTN：Alternate,Alternative 备用的
AP：Autopilot自动驾驶
APU：Auxiliary Power Unit 辅助动力装置，
ATA：Air Transport Association of America 美国航空运输协会
ATC：Air Traffic Control空中交通管制
CAAC：Civil Aviation Administration of China 中国民航总局
CAB：Cabin客舱，座舱
DH：Decision Height 决断高
DME：Distance Measuring Equipment 测距机
ECAM Electronic Centralized Aircraft Monitoring 飞机电子集中监控（系统）
EFIS：Electronic Flight Instrument System：电子飞行仪表系统
EMER：Emergency 应急的，紧急的
FAA：Federal Aviation Administration 联邦航空局（美国）
FADEC：Full Authority digital Engine Control 全权数字式发动机控制
FAR：Federal Aviation Regulation 联邦航空条例（美国）
FIG Figure 图
FMC：Flight Management Computer 飞行管理计算机
GPS：Global Positioning System全球定位系统
GPWS：Ground Proximity Warning System 近地警告系统
IATA:International Air Transport Association国际航空运输协会
ICAO: International Civil Aviation Organizition 国际民航组织
ILS：Instrument Landing System 仪表着陆系统；
ISA：International Standard Atmosphere 国际标准大气
ISO International Standardization Organization 国际标准化组织
JAA： Joint Aviation Administration 联合航空局（欧洲）
JAR: Joint Airworthiness Requirements 联合适航条例
MEL：Minimum Equipment List 最低设备清单
NAV：Navigation 导航
PFD：Primary Flight Display 主飞行显示器
PN Part Number 零件号
PTT: Push-to-Talk 按压通话
RA: Radio Altimeter, Radio Altitude 无线电高度表，无线电高度
SN: Serial Number 序号
TCAS：Traffic Alert and Collision Avoidance System 防撞系统；更多请参考机载防撞系统
VHF：Very High Frequency甚高频
VOR：VHF Omnidirectional Range 甚高频全向信标

民航常用名词解释

2009-04-06T03:04:00.004+08:00

本节内容介绍的是经常在民航相关新闻、文章中出现的一些常用专业用语、参数、缩略语的基本含义，不涉及较深的专业知识，当然有些定义、介绍不够专业、严谨、准确，还请见谅。

民航飞机基本参数:

机长：或称全长,指飞机机头最前端至飞机机尾翼最后端之间的距离。值得注意的是机长与机身长是不同的，机身长的概念较少使用，一般指机身段的长度。

机高：指飞机停放地面时，飞机外形的最高点（尾翼最高点）的离地距离。

翼展：指飞机左右翼尖间的距离。这个参数在实际运作中较为重要，要确定飞机滑行路线、停放的位置、安全距离时均以它作为重要指标。

最大起飞重量：指飞机适航证上所规定的该型飞机在起飞时所许可的最大重量。

最大着陆重量：是飞机在着陆时允许的最大重量，它要考虑着陆时的冲击对起落架和飞机结构的影响，大型飞机的最大着陆重量小于最大起飞重量，中小飞机两者差别不大。由飞机制造厂和民航当局所规定。

空机重量:或称飞机基本重量,指除商务载重（旅客及行李、货物邮件）和燃油外飞机作好执行飞机飞行任务准备的飞机重量。

民航飞机性能参数:

业载：业务载荷，也称商载。指飞机可以用来赚取利润的商业载荷，它包括3个部分。①旅客:总重量为座位数X旅客平均重量，我国一般旅客(含随身携带的行李)平均重量按75公斤计算。②行李:这里指旅客托运的行李,在飞机货舱。③货物：在客机上和行李混装，由于行李是散装的，占体积较大，因而目前货物多采用集装箱或集装盒以充分利用容积，来装运行李。

巡航:飞机完成起飞阶段进入预定航线后的飞行状态称为巡航。飞机发动机有着不同的工作状态，当发动机每公里消耗燃料最少情况下的飞行速度，称为巡航速度。

爬升速度（爬升率）：指飞机每分钟上升的垂直方向的高度。

航程：飞机起飞后、中途不降落，不加燃料和滑油，所能飞跃的距离。

民航基本概念:

民航飞机组成：主要由机翼、机身、动力装置、起落装置和稳定操纵机构组成

机翼：产生飞行所需升力，支持飞机在空中飞行，也有稳定操纵的作用；

机身：装载机组成员、旅客、货物和提供安装飞机操纵机构的场所，同时机身也将飞机其它部件连接在一起形成整体；

动力装置：产生飞机的前进动力，除常听说的发动机外，还包括一系列保证发动机正常工作的系统及其附件；

起落装置：支持飞机并使飞机在地面或水面起落、滑行和停放；

稳定操纵机构：飞行中维持飞机稳定和平衡，并使飞机能被操纵、控制，包括尾翼、副翼等操纵舵面和相关传动机构。

航路：根据地面导航设施建立的供飞机作航线飞行之用的具有一定宽度的空域。

航线：飞机飞行的路线称为航线，航线确定了飞机飞行的具体方向、起讫和经停地点。

航班：是指飞机由始发站按照规定的航线飞行经过经停站至终点站或直接到达终点站的运输生产飞行。

机场（航空港）：供航空器起飞、降落和地面活动而划定的一块地域或水域，包括该区域内的各种建筑物和设备装置。

空勤人员:在飞行中的航空器上执行任务的人员，通常包括飞行人员、乘务人员、航空摄影员和安全保卫员。

飞行人员:在飞行中直接操纵航空器和航空器上航行、通信设备的人员，包括驾驶员、领航员、飞行通信员、飞行机械员。

航班正常:指飞机在班期时刻上公布的离站时间前关好机门,在公布的离站时间后15分钟内起飞,在公布的到达站着陆的航班，反之则为航班不正常。　

飞机维修工作的分类

2009-04-06T02:57:00.002+08:00

飞机的维修部门是民航正常运作的重要保障单位，负责保持飞机处于适航和“完好”状态并保证航空器能够安全运行。

“适航”意味着航空器符合民航当局的有关适航的标准和规定；
“完好”表示航空器保持美观和舒适的内外形象和装修。
　　
一般而言，飞机的维修部门分为两级：
　　
一级是维修基地：进行内厂维修。维修基地是一个维修工厂，它具备大型维修工具和机器以及维修厂房，负责飞机的定期维修、大修，拆换大型部件和改装。
　　
二级是航线维修也称为外场维修，飞机一般不进入车间，航线上对运行的飞机进行维护保养和修理，这类航线维护包括航行前、航行后和过站维护。
　　
小型航空公司可以没有自己的维修基地，把高级的定检和修理工作委托给专门的维修公司或大航空公司维修基地完成。
　　
下面按对飞机的维修工作进行具体分类介绍：
　　
航线维修（维护）：也称为低级维修；包括：　　

航行前维护：

每天执行飞行任务前的维护工作；
　　
过站（短停）维护：每次执行完一个飞行任务后，并准备再次投入下一个飞行任务前，在机场短暂停留期间进行的维护工作；
　　
过站维护主要是检查飞机外观和飞机的技术状态，调节有关参数，排除故障，添加各类工作介质（如润滑油、轮胎充气等），在符合安全标准的前提下，适当保留无法排除并对安全不够成影响的故障，确保飞机执行下一个飞行任务。
　　
航行后维护：

也叫过夜检查，每天执行完飞行任务后的维护工作，一般在飞机所在基地完成，排除空、地勤人员反映的运行故障、彻底排除每日飞行任务中按相关安全标准保留的故障项目，并做飞机内外的清洁工作。
　　
以上各类维护定义仅针对一般情况，依据具体飞行任务安排在各航空公司都有自己的相关规定，如飞机在基地停留超过一定时间就必须进行航行后维护，而不论当天飞行任务是否全部完成；飞机飞回基地作短暂停留期间也可能要按航行后维护标准执行维护工作。
　　
定期维修（维护）：也称为高级维修；
　　
飞机、发动机和机载设备在经过一段时间的飞行（飞行周期）后，可能发生磨损、松动、腐蚀等现象，飞机各系统使用的工作介质，如液压油、滑油等也可能变质和短缺，需要进行更换或添加，所以经过一段时间的飞行后，就必须进行相关的检查和修理，并对飞机各系统进行检查和测试，发现和排除存在的故障和缺陷，使飞机恢复到原有的可靠性，来完成下一个飞行周期的任务。
　　
目前，这种飞行周期的划分有两种方法
　　
前苏联飞机的定检周期：一般按每50小时、100小时、200小时、1000小时、2000小时...来划分的，中国国产飞机、发动机和机载设备一般也是按此方法划分定检周期
　　
欧美飞机的定检周期：一般按飞行小时或起落架次分为A、B、C、D检等级别。　　

一般来说4A=B，4B=C，8C=D。各类检查的飞行间隔时间主要因机型而定。　　

定检时飞机停场，按规定检查或更换一些部件，D检，又叫大修、翻修；是飞机长期运行后的全面检修，必须在维修基地的车间内进行，飞机停场时间在10天以上。D检是最高级别的捡修，对飞机的各个系统进行全面检查和装修。由于D检间隔一般超过1万飞行小时，很多飞机会在D检中进行改装或更换结构和大部件。理论上，经过D检的飞机将完全恢复到飞机原有的可靠性，飞机飞行将从“0”开始重新统计。
　　
A检无须专门的飞行日来作停场维修，利用每日飞行任务完成后的航行后检查时间来进行此项工作，对于同一机型A检的飞行间隔时间也不一定是固定的，飞机运营者、航空公司维修部门根据飞机的实际运行状况、维修经验的积累等进行相应调整，适当延长以减少不必要的维修费用。
　　
在实际运作中，飞机运营者、航空公司维修部门往往取消B检，把B检的项目调整到A检或C检工作中，以减少不必要的停场维修时间
　　
如中国波音737一般规定A检为200小时，没有B检，C检为3200小时。
　　
特种维修（维护）：　　

由于某种特殊原因而进行的维修，有些理论也把这类维修归到航线维修或定期维修
　　
这类维修一般包括：　　

经过雷击、重着陆或颠簸飞行后对某些设备、飞机结构的特定部位进行的特别检查和修理；
　　
受外来物撞击、碰伤后的修理；
　　
发现飞机某部位不正常发生腐蚀后的除锈、防腐处理
　　
按适航部门或制造厂家的要求对飞机进行加、改装工作
　　
两次D检中加做的中检（IL检），或进行客舱翻新

飞机发动机原理

2009-04-06T02:46:00.003+08:00

涡轮螺旋桨发动机

一般来说，现代不加力涡轮风扇发动机的涵道比是有着不断加大的趋势的。因为对于涡轮风扇发动机来说，若飞行速度一定，要提高飞机的推进效率，也就是要降低排气速度和飞行速度的差值，需要加大涵道比；而同时随着发动机材料和结构工艺的提高，许用的涡轮前温度也不断提高，这也要求相应地增大涵道比。

对于一架低速（500～600km/h）的飞机来说，在一定的涡轮前温度下，其适当的涵道比应为50以上，这显然是发动机的结构所无法承受的。　　

为了提高效率，人们索性便抛去了风扇的外涵壳体，用螺旋桨代替了风扇，便形成了涡轮螺旋桨发动机，简称涡桨发动机。涡轮螺旋桨发动机由螺旋桨和燃气发生器组成，螺旋桨由涡轮带动。

由于螺旋桨的直径较大，转速要远比涡轮低，只有大约1000转/分，为使涡轮和螺旋桨都工作在正常的范围内，需要在它们之间安装一个减速器，将涡轮转速降至十分之一左右后，才可驱动螺旋桨。这种减速器的负荷重，结构复杂，制造成本高，它的重量一般相当于压气机和涡轮的总重，作为发动机整体的一个部件，减速器在设计、制造和试验中占有相当重要的地位。　　

涡轮螺旋桨发动机的螺旋桨后的空气流就相当于涡轮风扇发动机的外涵道，由于螺旋桨的直径比发动机大很多，气流量也远大于内涵道，因此这种发动机实际上相当于一台超大涵道比的涡轮风扇发动机。　　

尽管工作原理近似，但涡轮螺旋桨发动机和涡轮风扇发动机在产生动力方面却有着很大的不同，涡轮螺旋桨发动机的主要功率输出方式为螺旋桨的轴功率，而尾喷管喷出的燃气推力极小，只占总推力的5%左右，为了驱动大功率的螺旋桨，涡轮级数也比涡轮风扇发动机要多，一般为2～6级。　　

同活塞式发动机＋螺旋桨相比，涡轮螺旋桨发动机有很多优点。首先，它的功率大，功重比（功率/重量）也大，最大功率可超过10000马力，功重比为4 以上；而活塞式发动机最大不过三四千马力，功重比2左右。其次，由于减少了运动部件，尤其是没有做往复运动的活塞，涡轮螺旋桨发动机运转稳定性好，噪音小，工作寿命长，维修费用也较低。而且，由于核心部分采用燃气发生器，涡轮螺旋桨发动机的适用高度和速度范围都要比活塞式发动机高很多。在耗油率方面，二者相差不多，但涡轮螺旋桨发动机所使用的煤油要比活塞式发动机的汽油便宜。　　

由于涵道比大，涡轮螺旋桨发动机在低速下效率要高于涡轮风扇发动机，但受到螺旋桨效率的影响，它的适用速度不能太高，一般要小于900km/h。目前在中低速飞机或对低速性能有严格要求的巡逻、反潜或灭火等类型飞机中的到广泛应用。

螺桨风扇发动机

螺桨风扇发动机是一种介于涡轮风扇发动机和涡轮螺旋桨发动机之间的一种发动机形式，其目标是将前者的高速性能和后者的经济性结合起来，目前正处于研究和实验阶段。

螺桨风扇发动机的结构　

它由燃气发生器和一副螺桨-风扇（因为实在无法给这个又象螺旋桨又象风扇的东东起个名字，只好叫它螺桨-风扇）组成。螺桨-风扇由涡轮驱动，无涵道外壳，装有减速器，从这些来看它有一点象螺旋桨；但是它的直径比普通螺旋桨小，叶片数目也多（一般有6～8叶），叶片又薄又宽，而且前缘后掠，这些又有些类似于风扇叶片。

涡轮风扇发动机的原理

在飞行速度不变的情况下，涵道比越高，推进效率就越高，因此现代新型不加力涡轮风扇发动机的涵道比越来越大，已经接近了结构所能承受的极限；而去掉了涵道的涡轮螺旋桨发动机尽管效率较高，但由于螺旋桨的速度限制无法应用于M0.8~M0.95的现代高亚音速大型宽体客机，螺桨风扇发动机的概念则应运而生。

由于无涵道外壳，螺桨风扇发动机的涵道比可以很大，以正在研究中的一种发动机为例，在飞行速度为M0.8时，带动的空气量约为内涵空气流量的100倍，相当于涵道比为100，这是涡轮风扇发动机所望尘莫及的，将其应用于飞机上，可将高空巡航耗油率较目前高涵道比轮风扇发动机降低15%左右。

同涡轮螺旋桨发动机相比，螺桨风扇发动机的可用速度又高很多，这是由它们叶片形状不同所决定的。普通螺旋桨叶片的叶型厚度大以保证强度，弯度大以保证升力系数，从剖面来看，这种叶型实际上就是典型的低速飞机的机翼剖面形状，它在低速情况下效率很高，但一旦接近音速，效率就急剧下降，因此装有涡轮螺旋桨发动机的飞机速度限制在M0.6~M0.65左右；而螺桨-风扇的既宽且薄、前缘尖锐并带有后掠的叶型则类似于超音速机翼的剖面形状，这种叶型的跨音速性能就要好的多，在飞行速度为M0.8时仍有良好的推进效率，是目前新型发动机中最有希望的一种。

当然，螺桨风扇发动机也有其缺点，由于转速较高，产生的振动和噪音也较大，这对舒适性有严格要求的客机来讲是一个难题。另外，暴露在空气中的螺桨-风扇的气动设计也是目前研究的难点所在。

冲压喷气发动机

冲压喷气发动机的诞生早在1913年，法国工程师雷恩•洛兰就提出了冲压喷气发动机的设计，并获得专利。但当时没有相应的助推手段和相应材料，只停留在纸面上。 1928年，德国人保罗•施米特开始设计冲压式喷气发动机。最初研制出的冲压发动机寿命短、振动大，根本无法在载人飞机上使用。于是1934年时，施米特和G•马德林提出了以冲压发动机为动力的“飞行炸弹”，于1939年完成了原型。后来这一设计就产生了纳粹德国的V-1巡航导弹。此外纳粹德国还曾试图将冲压喷气发动机用在战斗机上。1941年，特劳恩飞机实验所主任、物理学家欧根•森格尔博士在吕内堡野外进行了该类型发动机的试验，但最终未能产生具有实用意义的发动机型号。

冲压喷气发动机的原理

冲压喷气发动机的核心在于“冲压”两字。

冲压发动机由进气道（也称扩压器）、燃烧室、推进喷管三部组成，比涡轮喷气发动机简单得多。冲压是利用迎面气流进入发动机后减速、提高静压的过程。这一过程不需要高速旋转的复杂的压气机，是冲压喷气发动机最大的优势所在。进气速度为3倍音速时，理论上可使空气压力提高37倍，效率很高。高速气流经扩张减速，气压和温度升高后，进入燃烧室与燃油混合燃烧。燃烧后温度为2000一2200℃，甚至更高，经膨胀加速，由喷口高速排出，产生推力。因此，冲压发动机的推力与进气速度有关。以3倍音速进气时，在地面产生的静推力可高达200千牛。

冲压喷气发动机与其他推进方式结合后，衍生了多种有特色的发动机，如火箭/冲压组合发动机、整体式火箭冲压发动机等。冲压喷气发动机目前分为亚音速、超音速、高超音速三类。

亚音速冲压发动机　　

亚音速冲压发动机使用扩散形进气道和收敛形喷管，以航空煤油为燃料。飞行时增压比不超过 1.89，飞行马赫数小于 0.5时一般不能正常工作。亚音速冲压发动机用在亚音速航空器上，如亚音速靶机。

飞机跑道为何南方长北方短

2009-04-06T02:44:00.001+08:00

一个现代化机场，跑道大多长3000～4000米，宽40米以上。对如此长的跑道，有人可能会问：为何跑道要修这么长，且南方的跑道比北方的更长呢？　　　　　

跑道长度首先要满足计划使用该机场的多种飞机的安全起降要求，通常以最高机型的起降距离为主要依据。如新建一座机场，拟起降波音747飞机，因该机起飞距离需3000余米，方可离地升空，所以跑道长度要选择在3200米以上。不过跑道长度还应依据当地的海拔高度、气温以及跑道坡度等数据综合计算，然后才能确定跑道的长度。　　　　　

按照空气动力学原理，飞机起飞的滑行速度与空气的密度关系很大，当实际气温比标准气温高10度时，飞机起飞的滑行距离就要增加10%～11%。这是因为，当气温较高时，空气的密度减小，使发动机的推力和螺旋桨的拉力减小，飞机的滑行速度相对会慢一些。在这种情况下，要使飞机达到规定的起飞速度，就必须加长飞机在跑道上的滑行距离。当气温降低时，空气的密度增大，飞机增速快，相对于温度高时，飞机可以缩短在地面的滑行距离而达到起飞速度。

中国南方气温一般都高于北方，所以民航客机在南方的机场起飞时，其在地面的滑行距离就比在北方机场滑行的距离要长。与此相应，中国南方机场跑道设计的长度，通常要比北方机场的跑道长。

飞机上的电力与灯光

2009-04-06T02:40:00.001+08:00

黑夜里当我们抬头仰望，偶尔会看到一架闪烁着彩色灯光的飞机掠过，它那华丽的身影是由灯光来装点的，给所有看见它的人留下深刻的印象。

飞机不仅需要用电让许许多多的灯亮起来，其他各种用电器件也有15000多件。例如：厨房的加热炉、飞机上的防冰装置、驱动各种装置的电动机等都是用电大户；机上的各种仪表是用电小户，用电量不足全部用电量的5％，但是要求所供的电压稳定、频率稳定。因为如果仪表的指示不稳定，它所造成的后果对飞机来说是非常严重的。

飞机上装有自己的发电设备，它不仅重量轻、功率大而且所发的电的质量也高。飞机在运行的任何时候都不能停电。为此，飞机上的供电系统是多余度的，它具有三条防线。大型客机用两台发动机带动两台发电机。

每一台发电机所发出的电力都足以供给全飞机的需要。平时两台发动机同时工作，但每台都不是满负荷运转。一旦，其中某一台发生故障，剩下的一台立刻进入满负荷工作状态，这是第一条防线。除了上述发电机外，在机尾又加装了一个小型的涡轮发动机和发电机，它的名字是辅助动力装置。这台发动机的功率虽然不大，仅仅用于这台发电机，但这台发电机的功率比机上其他两台发电机的功率大。万一前面提到的那两台发电机同时出现故障时，这台辅助动力装置就能承担起为飞机提供全部电力的责任。这是第二道防线。

飞机在起飞前和落地后，两台主发电机停止工作，此时驾驶员就启用这台辅助动力装置为飞机提供电力，保证机上的灯光照明、空调等各种用电。这样做也能为飞机节约大量的燃油。现代客机上还装设有直流电系统，有容量很大的蓄电池。正常情况下，发电机经变流器产生出直流电向使用直流电的设备供电，它同时也使蓄电池充电。蓄电池能起到调节电压的作用，也用于启动发动机。假定出现了前述的三台发电机都发生了故障的特殊情况，此时蓄电池就是第三道防线，由它向飞机供电。当然了，蓄电池贮存的电量毕竟有限，它只能保证向重要的设备和仪表供应电力。

飞机上装有各式各样的灯。在客舱和驾驶舱内都装有柔和的日光色照明灯；在驾驶舱中的仪表板上装的是可以自动调节亮度的灯，它发出的光线不致于使驾驶员眼睛疲劳；在客舱中每个座位的上方还装有专供每位旅客使用的阅读灯；客舱通道上还装有紧急备用灯等等。但是最能引起地面上的人对飞机注目的是飞机外部的灯光。缤纷的色彩、闪烁不停的灯光把夜航的飞机打扮得如同天使一般。这种灯不是为了好看的，它们是航行灯和防撞灯，是为了防止碰撞用的。

航行灯安装在机翼的两个翼尖和垂直尾翼的顶端。民航条例规定左翼尖的灯光为红色、右翼尖的灯光为绿色、尾翼是白(黄)色灯光。根据飞机的航行灯是“左红右绿中间黄”这条规则，从一架飞机航行灯的颜色就可以判断出它是朝你飞来还是背离你而去。这一点对夜航的飞行安全非常重要。防撞灯被装在机身的上方或下腹部，这种灯亮度很强并且按一定的频率不停地闪动，通常每分钟闪动90次。颜色有两种，有的飞机用红白两色，有的飞机用强烈的青白色闪光灯。大型飞机一般安装3个以上的防撞灯，使它在很远的距离外就可以被发现。

为了帮助驾驶员在飞机着陆及滑行时看清楚下面及前面的跑道，在飞机上还装有着陆灯和滑行灯，其作用相当于汽车的前灯但功率都很大，能把飞机前方50米的距离照得很亮。着陆灯是当飞机下降到离跑道不远时使用的，灯光照向下方，而滑行灯是飞机着陆后用的，灯光照向前方。这两个灯的开关由驾驶员控制。

机翼会不会突然折断？

2009-04-06T02:39:00.000+08:00

机翼会不会突然折断？

实际上，如果有足够的力量，机翼是可以折断的。

对每个新机型，波音都要做机翼弯曲折断试验。

折断机翼需要的力量比实际情况要大得多。

你可能在飞机穿过湍流时看见过机翼摆动。机翼设计得很灵活，其原因之一就是保证不折断，因此机翼是非常坚固的。

民航飞机需要飞多远

2009-04-06T02:37:00.001+08:00

哪一种是飞得最远的民航机呢?

回答这个问题之前，我们先了解一下民航飞机发展中追求的现实目标是什么?

军用飞机追求性能而不大考虑经济代价；民航机则不然，首要考虑的是经济因素、市场因素。

仅追求技术性能而忽视上述因素，最后只能以失败告终，“协和”号就是一个最好的例证。

民航飞机能飞多远不是技术问题，而是市场因素决定需要它飞多远。地球的直径是12742千米，周长是40030千米，地球上最远的两点之间的距离也就是地球周长的1／2，差不多是20000千米。

因此我们可以得出结论：民航机的航程不需要超过20000千米。仔细研究一下就会发现民航的航线起点和终点都在人口相对集中的城市，超长航线的起止点只有设在大城市中才会有足够的旅客。这样一来，民航飞机的最大航程为l6500千米就够了。

欧洲空中客车公司的A340型飞机和波音公司的777—200型是现在航程最远的飞机。它们的最大油量航程为13700米。

如果减少载客或载货量的话，都可以飞行16500千米的距离。估计不会有哪家飞机制造厂为了哗众取宠而投入大量资金去创造什么飞机最大航程的纪录。

为什么民航飞机没有降落伞？

2009-04-06T02:35:00.000+08:00

如果您经常乘坐飞机，会发现飞机上没有配备降落伞。

这是因为如果每个乘客都配备一顶降落伞，就会大大增加飞机的重量，而且会占去很多空间，大大影响飞机的营运能力；再说，乘客们并不是每个人都能掌握跳伞技术；最主要的是，飞机是在高空高速飞行，与一般的跳伞运动和低空离机不同，即使发生意外也无法打开舱门跳伞。

如今，民航飞机的性能越来越先进，安全系数极高。因此您大可不必担心客机在飞行中会发生意外。

喷气式发动机安全吗？

2009-04-06T02:34:00.000+08:00

喷气式发动机非常安全。事实上，因为飞机发动机故障而造成的意外事故或备降极为少见。

飞机事故多数是人为失误造成的。飞行中出现乘客突发疾病则是导致备降的主要原因。　　

对发动机故障的担忧是可以理解的，这是从活塞时代延续下来的观念。

喷气发动机比螺旋桨发动机可靠得多。

自20世纪50年代人类进入喷气时代以来，飞机的可靠性有了显著提高。

先进的发动机设计使现代发动机比以往任何时候都可靠。

飞行离不开仪表

2009-04-06T02:33:00.000+08:00

飞机在空中飞行，驾驶员时刻要知道当时的飞行高度、速度、所在位置、飞行姿态、燃油消耗情况等许许多多数据。根据这些数据的变化，操纵调整飞行状态以便与空中环境相适应。

早期的飞机上只安装了很少的仪表，全靠驾驶员用自己的耳目观察及用大脑分析飞行情况来驾驶飞机。

在低空低速飞行时，用这种方式操纵飞机还勉强可以保证安全飞行。

飞行速度和飞行高度增加以后，仅靠驾驶员的感觉就无法适应这种种变化，各种功能的飞行仪表被大量研制出并装置在飞机上。

这些仪表可以准确地测量出飞机飞行时的各种参数。驾驶员只需要注意观察仪表上显示的数据，就能准确地知道飞机所处的状态。

飞行仪表就好比是飞机的耳目，依靠它们，飞机才不会在天空中“瞎”飞。

进入20世纪70年代，使用电子显像技术以及电子计算机技术对飞机上的仪表装置进行了一次大改造。电子计算机不仅可以收集处理各种参数，而且可以据此进行分析比较，发布指令甚至代替人去操纵飞机，飞机真好像有了自己的“大脑”。

电子显像管可以把几十甚至几百条信息用醒目的符号、鲜明的色彩映现在为数不多的屏幕上。驾驶舱过去的模样完全改变了。

老式飞机中，驾驶舱内设5个位置，分别是：正、副驾驶员、飞行机械师、报务员、领航员。他们每人面前都有一大堆仪表和操纵装置，个个都忙个不停地工作。正、副驾驶员负责驾驶飞机；飞行机械师管理着发动机；报务员的任务是通过收发电报与外界联系；领航员则根据飞行速度、风速、地图等不断计算着飞机的位置及航向。根据领航员的计算结果，驾驶员才能驾驶飞机在正确的航道上飞行。

现代飞机的驾驶舱内，只有正、副驾驶员在驾驶飞机。位于他们面前的是整洁明亮的仪表板，好几块显示屏上闪烁着各种数据和图形。驾驶员除了在飞机起飞和降落时全神贯注地操纵飞机外，在飞行的其余大部分时间里，他们都只是神态从容地用眼睛监视着电脑自动操纵飞机。这种变化极大地加强了飞行的安全性。

最近30年以来，飞机制造业方面最大的进步主要表现在机上的仪表和电子仪器的先进性上。

从前每架飞机制造的成本中，仪表所用资金只占5％左右，而现在超过30％，而且这种上升的趋势仍在不断发展。

飞行中听到的那些古怪噪音是什么？

2009-04-06T02:31:00.000+08:00

在航空旅行的初期阶段，人们普遍把飞机称为“飞行机器”，事实上就是那么回事。

在飞行中你处于一个巨大的复杂机器中。因此，听到许多古怪的声音不足为奇。其中一些声音如下：　　

起飞之前和近地着陆时像钻孔机似的尖利噪声----那是飞机张开机翼上的副翼和前缘缝翼的声音。这些金属板张开时能增加机翼的面积和曲率，有助于低速阶段的飞行。你听到的是传动装置张开那些金属板所发出的声音。　　

飞机起飞前的尖声呜鸣----那是发动机为起飞而加速转动发出的声音。飞机一旦进入空中，飞行员将关小油门。飞机巡航时发动机的声音从呜鸣变为近似蜂鸣。　　

起飞或穿越湍流时的格格声----那是发动机在起飞时振动或飞行遇到湍流期间，顶部行李箱和机舱其它部位物品互相挤撞发出的声音。那不是飞机的断裂声！　　

起飞后地板下面发出的重击声----那是起落架收进机腹和起落架舱门关闭的声音。　　

着陆之后的咆哮声----那是飞机接触跑道时帮助其减速的反推装置发出的声音。反推装置将进入发动机的气流向相反方向转换，因此声响巨大。飞机在设计上是使用刹车的，但是机组通常利用反推装置帮助减少刹车系统的磨损。

飞行中舱门能打开吗？

2009-04-06T02:30:00.000+08:00

多年来，好莱坞制造了不少人被吸出飞机的毛骨悚然的惊险镜头。这成为一些人最可怕的噩梦，但也是最不可能发生的事情。　　

首先,民用飞机是用极为坚固的材料制造的。这些材料重量轻，但是结构极为坚固，甚至还有“容错”设计，就是说如果结构的一个部分出了问题，其它部分将承受那部分的荷载，飞机将继续安全飞行。

另外还有一个综合项目，来保证老龄飞机的结构完整，这个项目包括对飞机进行定期检查、更换结构部件和改装等。　　

至于舱门，飞机一旦进入空中并加压，舱门是无法打开的。为了便于旅客呼吸和感觉舒适,飞机要加压至相当于8000英尺高空的大气压。由于飞机通常在30000英尺的高空巡航，飞机内部的气压比外部高得多，这个压差的存在使舱门不可能打开，即便有人想这样做也不可能。　　

如果有必要紧急着陆，飞行员在飞机下降时会使客舱慢慢释压，这样在飞机着陆之后就能立即打开舱门。紧急出口可在飞机着陆后立即打开。

湍流危险吗？

2009-04-06T02:29:00.001+08:00

湍流可能会很危险，因此最好保持坐姿并系好安全带。

飞行员通常知道何时将要进入湍流，因为他们定时观看气象信息，并用无线电与前方的其他飞行员对话。

然而，飞机有时会突然遭遇湍流，尤其是看不到的（清洁空气）湍流。

飞机的设计足以抵抗湍流，甚至严重的湍流，但是乘客如果在湍流发生时站立或者在通道行走，可能很容易失去平衡。

在发生严重湍流时，就坐的乘客如果不系安全带，其头部也有可能碰撞顶部行李箱。

因此，最好的保护措施是保持坐姿并系好安全带。如果站立或在通道中行走，要抓住顶部行李箱或座椅靠背。

乘坐飞机时，为什么晴空也会有颠簸 ?

2009-04-06T02:27:00.001+08:00

经常乘坐飞机的人都知道，飞机进入云层后会有颠簸产生，特别是在淡积云、强雨区中颠簸尤为强列，但在晴空飞行时比较平稳。但在晴空万里的蓝天中，有时也会像平静的海面下藏有暗流一样，偶尔会出现强烈的流动气流，使飞机产生强烈颠簸，即晴空颠簸。

它一般产生在7000米以上的高空，宽约100公里、厚约1000米的范围内。

这种颠簸虽然不可能造成恶性飞行事故，但机组处理不当，也可以造成旅客受伤，甚至危及人身安全。
在飞机遇到晴空颠簸时，机组会采取措施脱离颠簸区，乘客则需留意坐椅上方系好安全带的提示灯，灯亮时，及时系好安全带，以防意外。

飞机起飞时乘客为什么要系好安全带？

2009-04-06T02:24:00.001+08:00

顾名思义，飞机起飞时乘客系好安全带的目的是为保护乘客的安全。

飞机在起飞的时候速度很快，而且因爬高原因有很大的角度，为防止因低空云、风或驾驶员操作原因出现飞机的颠簸、抖动、侧斜等，致使乘客因碰撞而受伤或其他意外事故，所以要求乘客在飞机起飞前系好安全带。

出于同样的目的，飞机在空中穿越云层或遇扰动气流时，飞机在下降着陆时，乘客也要系好安全带。

1993年4月东方航空公司的一架MD－11飞机在飞往美国途经太平洋上空时，因遇强烈气流加上操作不当出现剧烈颠簸，没有系好安全带的乘客几乎全部飞离座位，摔伤撞伤。而系好安全带的乘客（多为日本客人）则安然无事。

所以，只要飞机上显示出系好安全带的信号时，请您迅速照办。

飞机滑行、起飞、降落时旅客要注意什么

飞机滑行、起飞、降落是整个飞行过程中一些重要阶段，为保证您的安全顺利完成乘机旅行，请您做到 “三要三不要”。

“三要”是：要系好安全带，要收起小桌板，要把座椅调整到正常位置；
“三不要”是：不要离开座位，不要来回走动，不要打开行李架取（放）行李。

全天候飞机与全天候飞行员

2009-04-06T02:22:00.001+08:00

“全天候”是从外文翻译而来，原文的意思是“不论晴雨”，即不受风雨的限制。

飞机在空中飞行，受气象条件的限制很大，一般飞机在恶劣气象条件下或者是夜晚不能飞行。

随着科学技术的发展，飞机大量装备了电子设备，使飞机能够在复杂的气象条件下和夜晚飞行，具备此种性能的飞机被称为“全天候飞机”。

同样理由，能够在复杂气象条件下和夜晚飞行的飞行员被称为全天候飞行员。

中国民航根据飞行人员的技术水平、机场的起降气候条件和昼夜间飞行能力分为白天0、1、2号标准。如1/1标准飞行员是白天、夜间都具备飞行条件的飞行员，即“全天候飞行员”。

飞机误入雷区会有危险吗？

2009-04-06T02:17:00.000+08:00

飞机在9146米（3000英尺）以上的高空飞行时，一般不会遇上雷雨。

雷雨区的分布范围一般在几千米以下的积雨云区，飞机在接近雷雨区时会发生颠簸现象，如果误入雷雨区，驾驶员应尽快操纵飞机离开雷雨区，绕道而行，对飞机来说，雷雨区不是久留之地。

为防止飞机遭雷击，飞机上装有防雷电装置，它一般安置在机翼的翼尖处，亦叫“放电刷”。

飞机遭到雷击后，电流可以从“放电刷”中放出去，“放电刷”即起避雷针的作用。所以尽管舷窗外雷声滚滚、电光闪闪。但飞机安然无恙。旅客门尽可放心。特别是现代打中型飞机一般都装有气象雷达，加上地面的气象预报和驾驶员的正确操纵，绕过雷雨区和迅速脱离雷雨区是容易做到的。

飞机着陆机场上空突然出现雷雨怎么办？

2009-04-06T02:16:00.000+08:00

驾驶员从气象雷达和无线电联络中可以预先得知所去机场的气象条件。

如果该机场为雷雨天气，飞机可以到备降机场降落。

由于雷雨通常为阵雨，所以也可以在空中等待，雷雨过后，再进场着陆。

根据飞行计划，飞机上都装有一定的备用燃油，足以保证飞机飞到备降机场或空中至少飞行45分钟。

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喷气式发动机安全吗？

飞行离不开仪表

飞行中听到的那些古怪噪音是什么？

飞行中舱门能打开吗？

湍流危险吗？

乘坐飞机时，为什么晴空也会有颠簸 ?

飞机起飞时乘客为什么要系好安全带？

飞行原理简介（二）

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