Principles of Flight
Lift and the four forces
Understand the four forces - lift, weight, thrust and drag - and how they balance in steady flight. Learn the lift equation qualitatively: lift increases with air density, speed squared, wing area and lift coefficient. Know the angle of attack as the angle between the chord line and the relative airflow, and that the critical angle of attack is the only direct cause of a stall. A classic trap is assuming a stall depends on speed; it depends on angle of attack, and a stalled aircraft can stall at any speed and any attitude.
Drag and stability
Distinguish induced drag from parasite drag. Induced drag decreases with speed while parasite drag increases, giving a total drag curve with a minimum at best glide speed. Know the relationship between best glide, minimum sink and maximum range. Understand static and dynamic stability in pitch, roll and yaw, and the role of the tailplane and dihedral.
Controls and turning
Know how ailerons produce adverse yaw and how rudder coordinates the turn. Understand load factor in turns: load factor increases with bank angle, and stall speed rises with the square root of load factor. At 60° bank the load factor is 2, so stall speed rises by about 41%.
Worked example
If the stall speed in level flight is 60 kt, at 60° bank it becomes 60 × √2 ≈ 85 kt. A question offering 72 kt is testing whether you squared the load factor correctly.
Traps to watch
Questions often confuse the effect of flaps on stall speed (lower) with their effect on glide angle (steeper), or claim that a heavier aircraft always stalls faster - true at the same angle of attack and speed, but the practical answer depends on the conditions stated.