Principles of Flight
Lift and drag
Lift = ½ρV²SCL. At a given configuration and altitude the wing always stalls at the same critical angle of attack, regardless of speed, mass or bank. Induced drag decreases with speed; parasite drag increases with V².
Load factor
In a level turn, n = 1 ÷ cos(bank). Stall speed rises with √n. At 60° bank, n = 2, so stall speed increases by about 41%.
Stability and control
Static stability resists displacement; dynamic stability returns the aircraft over time. Swept wings at high Mach show pitch-up and tuck-under, and shock-induced separation causes buffet and control difficulty. An aft CG reduces longitudinal stability.
Worked example
An aircraft stalls at 50 kt in level flight. In a 60° bank level turn, VS = 50 × √2 ≈ 71 kt. At 75° bank, n = 1 ÷ cos 75° ≈ 3.86, so VS ≈ 50 × 1.96 ≈ 98 kt. Same aerofoil, same critical angle of attack, different speed.
Traps
Believing a heavier aircraft stalls at a higher angle of attack - it stalls at the same AoA but a higher speed; confusing IAS with true airspeed; assuming flaps raise the stall angle; forgetting that load factor raises stall speed.