FAA Flight Instructor Airplane (FIA)Aerodynamics and Principles of FlightEasy
A flight instructor explains that as air accelerates over the curved upper surface of a cambered wing, its static pressure decreases relative to the slower-moving air beneath the wing, creating a pressure differential that contributes to lift. This explanation is based on which principle?
- ABernoulli's principle
- BBoyle's law
- CThe Coriolis effect
- DNewton's third law of motion
Show answer & explanationAnswer & explanation
Correct answer: A. Bernoulli's principle
Bernoulli's principle states that as the velocity of a fluid increases, its static pressure decreases. Air flowing faster over the curved upper wing surface has lower pressure than the air below, creating a pressure differential that is one of the two commonly cited theories of lift generation.
Why the other options are wrong
- B. Boyle's law relates pressure and volume of a gas at constant temperature and does not describe lift generation.
- C. The Coriolis effect relates to the Earth's rotation and is unrelated to airfoil pressure distribution.
- D. Newton's third law explains lift through downward deflection of air (downwash), not pressure-velocity relationships.
Bernoulli's Principle
As the velocity of a fluid increases, its static pressure decreases; applied to airfoils, faster airflow over the curved upper surface produces lower pressure than the lower surface.
- One of two accepted theories of lift (with Newton's third law)
- Faster airflow = lower static pressure
- Works together with downwash (Newton's laws) to fully explain lift
Memory trick: Bernoulli = 'faster flow, lower pressure blow'