What is Vx?
- Best angle of climb
- Aircraft will gain the most amount of altitude over time
- 65 kts
What is Vy?
- best rate of climb
- aircraft will gain the most altitude in a given period of time
- 75 kts
What is Vr?
Rotations speed (When the nose leaves the ground).55 kts
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.
What is Vno?
- Maximum structural cruising speed
- Upper limit of green arc
- DO NOT EXCEED EXCEPT IN SMOOTH AIR
- 126 kts
What is Vfe?
- Max speed with flaps extended
- Upper white arc
What are the 4 left turning tendencies?
- Spiraling Slipstream
- Asymmetric Thrust (P Factor)
- Gyroscopic Precession
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
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
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
What is Gyroscopic Precession?
- Resultant is 90 degrees ahead of the action
- Ex. Pitch up, yaw right
- Ex. Yaw right, pitch down
What is density altitude?
- Pressure altitude corrected for nonstandard temperature
- Indicator of performance
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
What is an accelerated stall?
Stall that occur with G-forces on an airplane
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=load factor
What is the limit load factor?
he amount of stress or load factor that can be withstood before structural damage or failure occurs
What is the lift to drag ratio?
- Lift divided by drag
- Measures gliding efficiency of a plane.
What is L/D max?
the angle of attack that results in the least drag
What form of drag is highest at low airspeed?
What form of drag is highest at High airspeeds?
What is CG?
- Center of Gravity
- Point in the plane where all of the weight is concentrated
- Reference point for the three axis
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
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
What is the center of pressure/lift?
Point along the wing chord line where lift is concentrated
What happens as the angle of attack changes?
- High AOA causes it to move forward
- Low AOA causes it to move backward
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
When entering a side slip, What helps keep the airplane aligned with the relative wind?
The greater the surface area behind the CG
What is the keel effect?
the steadying influence exerted by the side area of the fuselage and vertical stabilizer (low-wing aircraft).
What is dihedral?
Upward angle of the plane's wings with respect to the horizontal axis
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.
What is ground effect?
Induced drag and excess speed in the flare may cause floating when within 1 wingspan above the surface