True or False: A propeller works the same as a wing in theory, but produces thrust.

• A. True
• B. False
• C. Not applicable
• D. Depends on speed

Answer: (A)

A propeller is basically a rotating wing. Each blade acts as an airfoil moving through the air, so it generates lift in the same way a wing does. Because the blade is rotating, the lift is redirected by the blade’s twist and angle, and the resulting force on the blade has a rearward component along the aircraft’s longitudinal axis. When you integrate this force over the entire propeller disk, that rearward component becomes forward thrust for the airplane. So the same aerodynamic principle—lift on an airfoil—applies, but the direction of the resulting force is what makes the propulsion possible. The idea that a propeller works like a wing in theory, but produces thrust, captures that relationship. The other choices aren’t fitting because the basic physics doesn’t depend on speed in a way that would invalidate the similarity, and the concept isn’t about something unrelated or inapplicable.