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32 Cards in this Set
- Front
- Back
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What is the function of the ailerons on an airplane? |
Ailerons rotate the airplane about its longitudinal axis.
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What is a stabilator?
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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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What is the function of the elevators on an airplane?
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Elevators rotate the airplane about its lateral axis.
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What is the function of the rudder on an airplane?
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The rudder rotates the airplane about its vertical axis.
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What is the purpose of an aileron balance cable?
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It ties the ailerons together in such a way that when one aileron deflects downward the other one is pulled upward.
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What is an aerodynamically balanced control surface?
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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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What is meant by differential aileron travel?
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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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What is a Frise aileron?
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An aileron with its hinge line set back from the leading edge so that when it is deflected upward, part of the leading edge projects below the wing and produces parasite drag to help overcome adverse yaw.
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What is a ruddervator?
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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 the elevators. When the rudder pedals are depressed, the ruddervators move differentially and act as a rudder.
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How much is a fairlead allowed to deflect a control cable?
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No more than 3°.
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Why are the control cables of large airplanes normally equipped with automatic tension regulators?
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The large amount of aluminum in the aircraft structure contracts so much as its temperature drops in flight that the control cables could become dangerously loose. The automatic tension regulators keep the cable tension constant as the dimensions of the aircraft change.
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In what publications could you find correct control surface movement for a particular airplane?
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In the Type Certificate Data Sheet for the airplane.
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What causes dissymmetry of lift produced by the rotor of a helicopter?
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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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Why do single–rotor helicopters use an auxiliary rotor on their tail?
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The thrust from the tail rotor counteracts the torque produced by the main rotor.
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Why is it important that the blades of a helicopter rotor system be in track?
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If the blades are not in track, vertical vibration can develop.
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What is the function of the collective pitch control of a helicopter?
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It changes the pitch of all the blades at the same time. The collective pitch controls the vertical flight of the helicopter.
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What is the function of the cyclic pitch control?
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It changes the pitch of the rotor blades at a particular point on their rotation to tilt the plane of the rotor. The cyclic pitch controls the lateral movement of the helicopter.
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What is the function of the tail rotor on a single main rotor helicopter?
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The thrust from the tail rotor 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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What is the purpose of the stabilizer system in a helicopter?
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A helicopter is statically stable but dynamically unstable. The stabilizer system restores the helicopter to level flight when outside forces cause it to pitch or roll.
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What is meant by a fully articulated rotor system?
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It is a rotor system in which the individual blades are free to flap, drag, and feather.
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What is meant by a semirigid rotor system?
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A two–blade rotor system in which the blades can feather, but cannot flap nor drag. The rotor hub is mounted on the mast with a teetering hinge that allows the entire rotor to rock as a unit.
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What is meant by a rigid rotor system?
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A rotor system that has freedom of motion about its feather axis only. The flexibility of the blades is sufficient to provide the needed flapping and dragging.
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What is the basic cause of low–frequency lateral vibration?
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The main rotor blades being out of static balance.
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What is the basic cause of low–frequency vertical vibration?
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One of the main rotor blades producing more lift than the other.
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What is usually the cause of high frequency vibration?
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The engine, cooling fan, or tail rotor.
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What is the most effective way to check a helicopter rotor for dynamic balance?
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Use a special computerized analyzer/balancer.
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Why is it important that control surfaces be statically balanced?
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An out–of–balance control surface can cause severe flutter.
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Where can you find the specifications for balancing the control surfaces of an airplane?
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In the aircraft maintenance manual.
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What in addition to static unbalance can cause a control surface to flutter?
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Worn hinges or improperly adjusted control cable tension.
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Where can you find instructions for jacking one wheel of an aircraft to change a tire?
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In the aircraft maintenance manual.
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Where can you find instructions for jacking the complete aircraft to perform a landing gear retraction test?
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In the aircraft maintenance manual.
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Where can you find instructions for hoisting an aircraft to replace wheels with floats?
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In the aircraft maintenance manual. |
