Aerodynamics: Lift, Drag, Stability and Control
Basic aerodynamics
Understand the four forces, the generation of lift by pressure distribution and Newtonian deflection, and the meaning of angle of attack, chord line and camber. Know the lift curve and the stall: as angle of attack increases beyond the critical angle, lift decreases and the wing stalls. Understand induced drag, parasite drag, and the drag curve.
Stability and control
Know the three axes (pitch, roll, yaw) and the corresponding controls (elevator, aileron, rudder). Understand static and dynamic stability, and the role of the centre of gravity and the neutral point. Know the effect of flaps and slats on lift and stall speed, and the meaning of Mach number and critical Mach.
Traps
- Assuming lift is only due to Bernoulli; both pressure and momentum change matter.
- Confusing induced drag (a by-product of lift) with parasite drag (form and skin friction).
- Forgetting that a forward centre of gravity reduces stability but improves manoeuvrability.
Worked example
If an aircraft stalls at 60 kt at 1 g, its stall speed at 2 g rises by the square root of 2, about 1.41, to roughly 85 kt. Load factor increases stall speed; this is why accelerated stalls occur at higher speeds.