A California team recently tested a wind-powered car that can actually outrun the wind, adding more fuel to a lingering physics debate.
The creators had funding from Google and Joby Energy to build the car, basically an aerodynamic foam chassis attached to a wind turbine, with the San Jose State University aerodynamics department.
The wheels turn the car's propeller, and the prop thrust pushes the car, which turns the wheels. It's not a perpetual motion machine, because the prop is also using wind energy as an external power source.
The toughest part was designing a transmission system to transfer power from the wheels to the propeller. Design and construction took almost a year.
The next step is a land-sailing record certified by the North American Land Sailing Association.