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.
2009年4月20日星期一
How Black Boxes Work
Flight Data RecordersThe 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
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.
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.
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.
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 TechnologySolid-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
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
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
2009年4月9日星期四
轻松一下
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．」
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．」
History of Aircraft Engines
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
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
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.
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
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。
（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。
2009年4月8日星期三
渦輪扇葉發動機 Turbofan Engine
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）
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
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.
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
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.
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
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
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。
2009年4月6日星期一
认识飞机的高度表
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。
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
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 )
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
..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
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 )
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.
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.)
ELEVATORSElevators 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 )
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.
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.
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.
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.
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 )
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 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.
DRAGDrag 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.
GRAVITYGravity 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-ForceA "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
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.
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.
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