Term
| what is the function of the ailerons on an airplane? |
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Definition
| ailerons rotate the airplane about its longitudinal axis. |
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Term
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Definition
| a single piece horizontal tail surface that acts as both the horizontal stabilizer and the elevators. A stabilator pivots about its front spar. |
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Term
| what is the function of the elevators on an airplane? |
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Definition
| elevators rotate the airplane about its lateral axis. |
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Term
| what is the function of the rudder on an airplane? |
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Definition
| the rudder rotates the airplane about its vertical axis |
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Term
| what is the purpose of an aileron balance cable? |
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Definition
| it ties the ailerons together in such a way that when one aileron deflects downward the other one is pulled up. |
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Term
| what is an aerodynamically balanced control surface? |
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Definition
| a surface with part of its area ahead of the hinge line. When the surface is deflected, the portion ahead of the hinge aids the movement. |
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Term
| what is meant by differential aileron travel? |
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Definition
| aileron movement in which the upward moving aileron deflects a greater distance than the one moving downward.The up aileron produces parasite drag to counteract the induced drag produced by the down aileron. |
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Term
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Definition
| an aileron with its hinge set back from the leading edge so that when it is defected upward, part of the leading edge projects below the wing and produces parasite drag to help overcome adverse yaw. |
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Term
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Definition
| movable control surfaces on a V-tail airplane that are controlled by both the rudder pedals and the control yoke. When the yoke is moved in or out, the ruddervators move together and act as elevators. When the rudder pedals are depressed, the ruddervators move differently and act as a rudder. |
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Term
| how much is a fairlead allowed to deflect a control cable? |
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Definition
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Term
| why are the control cables of large airplanes normally equipped with automatic tension regulators? |
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Definition
| keeps the cable tension constant as the dimensions of the aircraft changes with temperture change. |
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Term
| In what publication would you find correct control surface movement for a particular airplane? |
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Definition
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Term
| what causes dissymmetry of lift produced by the rotor of a helicopter? |
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Definition
| the forward speed of the helicopter produces dissymmetry of lift. The rotor blade that is traveling forward as the helicopter is flying produces more lift than the blade that is traveling rearward. |
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Term
| why do single rotor helicopters use an auxiliary rotor on their tail? |
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Definition
| the thrust from the tail rotor counteracts the torque produced by the main rotor. |
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Term
| why is it important that the blades of a helicopter rotor system be in track? |
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Definition
| vertical vibration can develop |
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Term
| what is the function of the collective pitch control of a helicopter |
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Definition
| changes the pitch of the rotor blades at the same time, controls vertical flight. |
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Term
| what is the function of the cyclic pitch control? |
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Definition
| changes pitch of rotor blades at a particular point in their rotation to tilt the plane of the rotor. controls lateral movement of helicopter. |
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Term
| what is the function of the tail rotor on a single main rotor helicopter? |
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Definition
| the thrust counteracts the torque of the main rotor to control the yaw of the helicopter. The control pedals change the pitch of the tail rotor blades to vary the thrust. |
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Term
| what is the purpose of the stabilizer system in a helicopter? |
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Definition
| restores the helicopter to level flight when outside forces cause it to pitch or roll. |
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Term
| what is meant by a fully articulated rotor system? |
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Definition
| individual blades are free to flap, drag,and feather. |
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Term
| what is meant by semi-rigid rotor system? |
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Definition
| two blade system, blades can feather, but cannot flap or drag. Hub is mounted on mast with a teetering hinge that allows entire rotor to rock as a unit. |
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Term
| what is meant by a rigid rotor system? |
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Definition
| has freedom of motion about its feather axis only.flexibility of blades provides needed flapping and dragging |
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Term
| what is the basic cause of low frequency lateral vibration? |
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Definition
| main rotor blades out of static balance. |
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Term
| what is the basic cause of low frequency vertcal vibration? |
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Definition
| one of the main rotor blades producing more lift than the other. |
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Term
| what is usually the cause of high frequency vibration? |
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Definition
| engine, cooling fan or tail rotor. |
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Term
| what is the most effective way to check a helicopter rotor for dynamic balance? |
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Definition
| a special computerized analyzer/balancer |
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Term
| why is it important that control surfaces be statically balanced? |
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Definition
| severe flutter can happen |
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Term
| where can you find the specs for balancing the control surfaces of an airplane? |
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Definition
| aircraft maintenance manual |
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Term
| what in addition to static unbalance can cause a control surface to flutter? |
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Definition
| worn hinges or improperly adjusted control cable tension |
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