Originally Posted by
CliffordK
With a spinnaker sail, that would be true. But with the propeller above, it isn't true. The vehicle actually runs direct down wind faster than the wind.
I know this is an old post but I'm pretty sure this is impossible. If you're going directly down wind, as you approach the speed of the wind the relative wind tends toward zero. Even if (magically) there is no tire and bearing drag, once you hit the speed of wind, relative wind disappears.