Wind-powered "race car"

The linked video is a very interesting look at a wind-powered land vehicle that is capable of sailing directly downwind faster than the wind. While the mind recoils at this notion, it is in fact possible.

While foiling sailboats can sail downwind faster than the true wind (both in terms of water speed and velocity made good to a mark directly downwind) they must sail at an angle to the true wind to do so. The AC75 is a prime example of this capability.

This land vehicle can sail directly downwind and achieve the same result because its propeller (analogous to a sail) is rotating, and that rotation puts its motion at an angle to the true wind. Effectively the propeller is sailing at an angle to the wind, but the vehicle it is on is traveling directly with the wind. If the wind stops blowing, the vehicle stops, so there is no perpetual motion thing going on. At least, that is my explanation ...

In any case, the video is interesting.

https://www.youtube.com/watch?v=jyQwgBAaBag

Are you checking my YT viewing history? I watched that last night, waiting for the '500 to start.

The basic concept, and the way he explained, it made it seem so simple - the wind is being controlled to apply a torque to the shaft, rather than directly impel the machine. It was a timely reminder that even the 'experts' get it wrong sometimes - and why it's so important to test one's ideas.

Quite some years ago there were rotary sail ships being built and tested, the sail in at least some being used to power a screw. Something you may also like to check out?

Gordon,

I reckon that there would be a lot of overlaps in YT viewing histories amongst the people on here.

This is also a video that I watched on the weekend, so when i saw the topic pop up I presumed that it would feature this video.

Uh, you do understand the concept of joking, don't you? ;-)

Veritasium is one of my subscribed bookmarks, he has some very interesting content on his channel.