Airplane Flight Controls Flashcards
What is the chord line?
- imaginary line that goes from the leading edge to the trailing edge
What is camber?
- curvature of the airfoil
What the primary flight controls?
- required to safely control an airplane during flight
- ailerons
- elevators
- rudder
What are ailerons?
- control roll about the longitudinal axis
- operated by cables and pulleys controlled by yoke
How do ailerons operate?
- attached to outboard trailing edge of each wing and move opposite of eachother
- ex. in right turn = right goes up left goes down
How to ailerons turn the airplane?
- upward deflected aileron decreased camber of wing resulting in decreased lift causing wing to lower
- downward deflected aileron increased camber of wing resulting in increased lift causing wing to raise
What is adverse yaw?
- downward deflected aileron produced more lift so it also produces more induced drag
- added drag causes nose to yaw in direction of raised wing
- countered by rudder
What are the 4 different types of ailerons?
- differential
- frise-type
- coupled ailerons and rudder
- flaperons
Differential Ailerons
- upward moving aileron raises higher than downward moving aileron
- produces increased drag on lowered wing to reduce adverse yaw
Frise-Type Ailerons
- raised aileron pivots on offset hinge, projecting leading edge into airflow creating drag and reducing adverse yaw
- forms slot for air to smoothly pass through making it more effective at higher AOA
Coupled Ailerons and Rudder
- ailerons and rudder are inter connected moving rudder and ailerons at same time via springs
Flaperons
- combination of flaps and ailerons
- control bank but can be lowered to function as normal flaps
What does the elevator control?
- controls pitch about the lateral axis
How does the elevator work?
- pulling yoke backwards deflects trailing edge up decreasing camber creating downward aerodynamic force
- tail moves down as nose moves up about the CG
What are the different types of elevators?
- t tail
- stabilator
T-Tail
- elevator is above most downwash created from propeller
- popular because it removes tail from exhaust blast from engine
How does slow flight affect a T-Tail?
- must be moved greater distance to raise nose due to lack of downwash acting on tail
- requires more control force during takeoff, landing, and stalls
Stabilator
- one piece horizontal stabilizer that pivots from central hinge point
- when yoke pulled back, trailing edge raises causing nose to point up
What are anti servo tabs?
- decrease sensitivity of stabilator
- moves in same direction of stabilator
- help prevent pilot from over controlling pitch
What does the rudder control?
- yaw about vertical axis
- used for coordination
How does the rudder work?
- when rudder is deflected into airflow creates horizontal force in opposite direction
- sideward lift due to increased camber
What are the secondary flight controls?
- improve performance characteristics or relieve control pressures
- flaps
- trim tabs
What are flaps?
- attached to inboard trailing edge of wing
- extended simultaneously
- increased induced drag and lift for any AOA
Why are flaps important?
- increased lift allows for takeoff at lower airspeed and improves climb performance
- produces more drag allowing for steeper descent angle at slow airspeeds
- decreases amount of runway required for takeoff and landing
What are the 4 types of flaps?
- plain
- split
- slotted
- fowler
Plain flaps
- simplest
- increase camber = increase lift
- significantly increased drag
- creates large wake behind wing
Split Flaps
- deflect from lower surface of wing
- increased drag due to turbulent airflow behind wing
- when fully extended produces high drag with little added lift
Slotted Flaps
- significantly increased lift compared to plain/split
- most popular today
- when lowered forms slot for air to pass through
- high pressure air from below combines with low pressure air above delaying airflow separation producing more lift
Fowler Flaps
- type of slotted flap which changes camber/increases wing area
- slides backwards on tracks
- first section creates a lot of lift but little drag
- section section creates a lot of drag but little lift
How are flaps controlled by the pilot?
- mechanically, electrically, or hydraulically powered
