Stall, Spin and High-Speed Aerodynamics
Stalls and spins
A stall occurs when the critical angle of attack is exceeded, regardless of speed, attitude or weight. Know the factors affecting the stall speed: weight, load factor, density altitude and configuration. Stall speed varies with the square root of load factor, so at 2 g the stall speed increases by about 41%. Recognise the stall warning signs and the recovery technique: reduce AoA, apply power as needed, and maintain coordinated flight. A spin requires both a stall and yaw; the spin phases are incipient, fully developed and recovery. Recovery is PARE: power idle, ailerons neutral, rudder opposite the spin, elevator forward to break the stall, then recover.
High-speed aerodynamics
Understand compressibility effects, the critical Mach number, shock-wave formation and Mach tuck. Know that swept wings raise the critical Mach number and that control effectiveness changes near the speed of sound.
Traps
Traps include assuming a stall requires low speed, forgetting that load factor increases stall speed, and applying aileron during a spin. Another trap is confusing critical Mach number with the speed of sound.
Worked example
Stall speed at 1 g is 50 kt; at 2 g, V_s = 50 × √2 ≈ 71 kt. Rule of thumb: multiply stall speed by the square root of the load factor.