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What is Vx?
- Best angle of climb
- Aircraft will gain the most amount of altitude over time
- 65 kts
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What is Vy?
- best rate of climb
- aircraft will gain the most altitude in a given period of time
- 75 kts
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What is Vr?
Rotations speed (When the nose leaves the ground).55 kts
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What is Va?
- Design Maneuvering speed
- Maximum speed you can stall an airplane
- 88-111 kts
- As weight increases, Va increases.
- As weight decreases, Va decreases.
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What is Vno?
- Maximum structural cruising speed
- Upper limit of green arc
- DO NOT EXCEED EXCEPT IN SMOOTH AIR
- 126 kts
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What is Vfe?
- Max speed with flaps extended
- Upper white arc
- 103
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What are the 4 left turning tendencies?
- Spiraling Slipstream
- Asymmetric Thrust (P Factor)
- Torque
- Gyroscopic Precession
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What is Spiraling Slipstream?
- Rotating propeller produces backflow of air which wraps around the airplane
- Causes a change in airflow around the vertical stabilizer - strikes the left side of vertical fin - causes the plane to yaw left
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What is Asymmetric Thrust (P Factor)?
- At a high angle of attack, the descending blade takes a greater bite than the ascending blade.
- Descending blade on right side makes the plane yaw to the left
- Most pronounced with a high power setting and a high angle of attack
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What is Torque (in relation to left turning tendency of a plane)?
- Newton's 3rd law - for every action there is an equal and opposite reaction
- Propeller rotates clockwise - causes torque reaction - rotating the plane left about the longitudinal axis
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What is Gyroscopic Precession?
- Resultant is 90 degrees ahead of the action
- Ex. Pitch up, yaw right
- Ex. Yaw right, pitch down
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What is density altitude?
- Pressure altitude corrected for nonstandard temperature
- Indicator of performance
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What is a stall?
a rapid decrease in lift caused by the separation of airflow from the wing's surface brought on by exceeding the critical angle of attack
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What is an accelerated stall?
Stall that occur with G-forces on an airplane
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What is the load factor?
- the ratio of the load supported by the airplane's wings to the actual weight of the airplane and its contents.
- The higher the load factor, the more lift required for the given weight
- n=L/W
- n=load factor
- L=Lift
- W=Weight
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What is the limit load factor?
he amount of stress or load factor that can be withstood before structural damage or failure occurs
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What is the lift to drag ratio?
- Lift divided by drag
- Measures gliding efficiency of a plane.
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What is L/D max?
the angle of attack that results in the least drag
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What form of drag is highest at low airspeed?
Induced drag
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What form of drag is highest at High airspeeds?
Parasitic drag
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What is CG?
- Center of Gravity
- Point in the plane where all of the weight is concentrated
- Reference point for the three axis
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What occurs when a CG is forward?
- Longer takeoff and roll with higher angle of attack needed
- More drag and lower stall speed
- more stable at all speeds
- easier to recover stall/spin
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What occurs with a CG is aft?
- Shorter takeoff and roll with lower angle of attack
- lower drag and higher stall speed
- more difficult to recover from stall/spin
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What is the center of pressure/lift?
Point along the wing chord line where lift is concentrated
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What happens as the angle of attack changes?
- High AOA causes it to move forward
- Low AOA causes it to move backward
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What is directional stability?
- Stability about the vertical axis
- Vertical tail acts like a weather vane
- Plane must have more surface area behind the CG that it has in front of it
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When entering a side slip, What helps keep the airplane aligned with the relative wind?
The greater the surface area behind the CG
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What is the keel effect?
the steadying influence exerted by the side area of the fuselage and vertical stabilizer (low-wing aircraft).
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What is dihedral?
Upward angle of the plane's wings with respect to the horizontal axis
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What is Sweepback?
- Design primarily to maintain the center of lift aft of the CG - creates lateral stability.
- If the airplane rotates about the vertical axis (yaws), For example yaws left the right wing has less sweep and a slight increase in drag, and the left wing has more sweep and less drag.
- Tends to force the airplane back into alignment with the relative wind.
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What is ground effect?
Induced drag and excess speed in the flare may cause floating when within 1 wingspan above the surface
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