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Four forces acting on an airplane
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Elements of an airfoil
- Leading edge
- Trailing edge
- Upper camber
- Lower camber
- Chord line
- Angle of attack
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Any surface such as a wing, rotor blade or propeller which produces an aerodynamic force when it passes through a stream of air
Airfoil
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Characteristic curve of the aerofoils upper and lower surfaces
Camber
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Describes a convex sruface
Positive camber
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Describes a concave surface
Negative camber
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Low speed wing generally have a _____ camber
Large, positive
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High speed wings generally have a ______ camber
Small, positive
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AOA
Angle of chord line in relation to the relative wind
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Describe the relation b/t AOA, lift, and velocity
Lift = V2 (AOA)
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Straight and level, unaccelerated flight; Maintaining altitude and constant speed
Equilibrium
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Aerodynamic stall
Exceeding the critical AOA
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What do you need to enter a spin
Stall and Yaw
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Controlling lift
- Aircraft design
- Pilot - change angle of attack, airspeed, shape of wing
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Rear portion or airfoil rotates downwards on a simple hinge mounted at the front of the flap
Plain flap
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Rear portion of the lower surface of the airfoil hinges downwards from the leading edge of the flap, while the upper surface stays immobile
Split flap
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Slides backwards flat, before hinging downwards, thereby increasing first chord, and then camber
Fowler flap
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Gap between the flap and the wing forces high pressure air from below the wing over the flap helping the airflow remain attached to the flaps, increasing lift compared to a split flap
Slottted flap
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The separation of airflow from the airfoil resulting in the loss of lift
Stall
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Explain stall recovery
- Decrease angle of attack
- Smoothly apply max power
- Adjust power as needed
- Recover to level flight
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Aggravated stall resulting in corkscrew path; One wing more stalled than the other
Spin
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Load factor ratio`
Load supported by the wings to Actual weight of the aircraft and contents
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Load factor ________ as angle of bank increase
Increases
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Increasing lead factor will cause an airplane to...
Stall at a higher speed
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Stalls that occur with G-forces being applied
Accelerated stalls
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Force =
Mass X acceleration
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Turning tendencies
- Torque
- Gyroscopic Precession
- Asymmetrical thrust
- Spiraling slipstream
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Example of torque
Propeller rotates clockwise causing torque which tends to rotate the airplane counterclockwise about the longitudinal axis
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Gyroscopic precession
Bike tire example
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Asymmetrical thrust (P-factor)
More thrust on the right resulting in left yaw
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Spiraling slipstream
Slipstream from propeller wraps around fuselage and hits left side of vertical fin (causes nose to yaw left)
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Any aircraft surface that interferes with the smooth flow of air around an airplane
Parasite drag
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Three types of parasite drag
- Interference drag
- Form drag
- Skin friction drag
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Produced by the shape of the object moving through the air
Form drag
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Interaction of varied currents that flow over an airplane and mix together
Interference drag
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Roughness of airplane surfaces
Skin friction drag
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Drag created by the production of lift
Induced drag
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Total drag =
Parasite + Induced
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Distance aircraft will travel forward, without power, in relation to altitude loss
Glide ratio
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Angle between glide path and horizon
Glide angle
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Phenomenon of less induced drag close to the ground
Ground effect (pocket of air)
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Causes and airplane to turn
Horizontal component of lift
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Three axes of rotation
- Longitudinal axis (ailerons)
- Lateral axis (Elevators)
- Vertical axis (rudder)
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Adverse yaw
In a turn, outside wing produces more lift, causing yaw toward the outside of turn
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Airframe, engines, and all items of operating equipment that have fixed locations and are permanently installed in the aircraft
Standard empty weight
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Weight of the pilot, passengers, baggage, usable fuel, and drainable fuel
Useful load
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Total weight of loaded aircraft, includes all fuel
Maximum ramp weight
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Maximum allowable weight for takeoff
Maximum takeoff weight
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Aviation Oil weight
7.5lbs/Gal
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A point along the wing chord line where lift is considered to be concentrated.
Center of Pressure (commonly called center of lift)
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Explain ground effect
Interference of the surface of the earth with the airflow patterns about the aircraft in flight
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Occurs when both wings are stalled and there is a yawing moment due to uncoordinated flight.
Spin
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A center-seeking force directed inward toward the center of rotation
Centripetal force
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How is centripetal force created?
Horizontal component of lift in turning flight
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Explain centrifugal force
Pulling G's (force that pushes you into your seat)
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Centrifugal force less that horizontal component of lift
Slipping turn
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Centrifugal force more than horizontal lift
Skidding turn
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Turning flight causes two additional forces to occur
Adverse yaw and overbanking
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Stability
Aircraft's ability to resist change
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