2025/07/26 by Svozil, Karl
#FOS: Physical sciences #General Physics (physics.gen-ph)
paper · doi:10.48550/arxiv.2507.22081
It is a well-documented yet counterintuitive fact that propeller-driven vehicles can travel directly downwind faster than the wind itself. The effect is not paradoxical once one recognizes that the vehicle is not pushed by the air alone but operates as a coupled mechanical system that extracts energy from the velocity difference between two media -- the moving air and the stationary ground or water. The ground provides the indispensable mechanical impedance, serving as an anchor that allows the drivetrain to convert relative motion into thrust. Through the analogies of a gearbox, a lever, and a sliding-boat thought experiment, this work shows that faster-than-the-wind travel arises naturally from the exchange of energy between coupled media and the presence of a fixed reference that sustains that exchange.