NCAA PPL Principles of Flight cheat sheet

Four forces in steady, unaccelerated flight: lift equals weight and thrust equals drag; any imbalance produces acceleration, not a new equilibrium.

Lift equation: L = ½ρV²SC_L. Lift rises with the square of airspeed, so doubling speed quadruples lift at a fixed angle of attack.

Angle of attack is the angle between the chord line and the relative wind; the critical angle (typically near 15–18° for light trainers) is fixed and independent of weight, bank, or airspeed.

Induced drag varies inversely with the square of airspeed and dominates at low speed and high angle of attack; parasite drag rises with the square of airspeed and dominates at high speed.

Total drag is the sum of parasite and induced drag; the minimum-drag point occurs where induced drag equals parasite drag, giving best glide (L/D max) speed.

Load factor n = 1/cos(bank angle) in a level turn; a 60° bank yields n = 2, raising stall speed by √2 (about 41%).

Stall speed in a level turn: V_S(turn) = V_S × √n. Accelerated stalls occur at higher airspeeds whenever load factor or abrupt control input pushes the wing past the critical angle.

Center of pressure moves forward as angle of attack increases; a forward CG increases stability and stall speed while lengthening takeoff and reducing cruise performance.

Adverse yaw results from asymmetric induced drag between wings in a turn; rudder applied in the direction of turn (coordinated with aileron) corrects it.

Lift equation: L = ½ρV²SC_L. Lift rises with the square of airspeed, so doubling speed quadruples lift at a fixed angle of attack.

Angle of attack is the angle between the chord line and the relative wind; the critical angle is fixed and independent of weight, bank, or airspeed.

Induced drag varies inversely with the square of airspeed and dominates at low speed and high angle of attack; parasite drag rises with the square of airspeed.

Total drag equals parasite plus induced drag; minimum drag occurs where induced drag equals parasite drag, giving best glide (L/D max) speed.

Load factor n = 1/cos(bank angle) in a level turn; a 60° bank yields n = 2, raising stall speed by √2 (about 41%).

Stall speed in a level turn: V_S(turn) = V_S × √n. Accelerated stalls occur at higher airspeeds when load factor or abrupt input exceeds the critical angle.

Center of pressure moves forward as angle of attack increases; a forward CG increases stability and stall speed while lengthening takeoff.

Adverse yaw results from asymmetric induced drag between wings in a turn; rudder applied in the direction of turn corrects it.