How a Wing Really Lifts 775,000 Pounds (Not What School Taught You)

The popular "equal transit time" explanation of lift says air over the top must travel farther to meet the air below at the trailing edge. Wind-tunnel tests show that's not true: the air over the top arrives first. What actually happens: the tilted, curved wing turns the passing air downward. Push air down, and the air pushes the wing up — which also means lower pressure above the wing and higher pressure below. At a 777-300ER's maximum takeoff weight of 775,000 lb spread over 4,702 sq ft of wing, that's about 165 lb per square foot — roughly one pound per square inch.

Notes: The wind-tunnel section is computed with ideal 2D potential flow (Joukowski airfoil at 6°, with the Kutta condition) — a representative profile, not the 777's exact wing section. The psi figure is an average at maximum weight, ignoring lift from the body and the tail.

Sources:
– University of Cambridge, "How wings really work":
– On the equal transit time fallacy (arXiv):
– Theories of lift (quotes NASA Glenn):
– Boeing, 777-300ER max takeoff weight 775,000 lb:
– Boeing 777 specifications (wing area):