I was kinda sceptical of the claims initially, but am coming round to thinking that it probably does work, although I am still waiting to hear a satisfactory explanation of why it works…
What I have gleaned so far is this:-
The wheels drive the prop, there is a ratchet mechanism that stops the prop driving the wheels.
This is not some kind of free energy machine, and it won’t move when there is no wind.
Apparently this effect has been known about since the ’60s.
At standstill, the wind pushes against the whole car, prop included, and this is enough to get the car moving slowly, at this point the prop is turning very slowly, and not really acting as a prop at all. The wind still keeps the same pressue on the car though, so it continues to accelerate slowly.
As the speed of the car increases, the prop will turn faster and faster, until at some point the prop will start to provide forward ‘lift’… at this point the car should start accelerating faster. I’d guess the limiting factor in how fast it can accelerate here would be the losses due to machanical friction in the drive train and aero drag, both by the buggy and the prop.
Now, the problem I have is working out how it still takes energy from the wind while travelling faster than the wind… I can’t quite see the mechanism for how this happens… and it’s bugging me!