Thanks for sharing, that's a great wrap-up

Interesting that some professors still won't admit that they were wrong, even with evidence like this. My opinion of professors has been reinforced

Couldnt looping a kite directly downwind could cause you to accelerate past zero wind (for a brief moment)?, just like the prop (aerofoil) idea?? Clever stuff anyway....

Now... back to work on that Perpetual motion machine, bye bye fossel fuel hello 'TheFish' super duper billion trillionaire

If its the same guy theres more info here: www.seabreeze.com.au/forums/Land-Yacht-Sailing/General/Downwind-Faster-than-the-Wind/?page=1

They joined this forum to try and explain it to us.

Most important thing to note is that the wheels push the propeller....

Initially, the thing just drifts downwind... as it begins to pick up speed, the propeller starts blowing wind upwind... literally pissing into the wind.

Unlike soggy trouser moments, this is good because the air leaving the propeller doesn't just fly off, instead the tailwind it pushes back up tight to the propeller.

Imagine a helicopter taking off vs one in flight. The helicopter needs less juice to get off the ground because it builds up a high pressure cushion of air that can't escape beneath it - the propeller blades are more effective getting lift in this air.

Or imagine dropping anchor and going downstream in a propeller boat, because the water is pushing onto the prop, the prop has more power.

Ok, so the propeller pushes air upwind into the wind. The prop drives the cart forward, making the cart go faster meaning the prop spins faster (pissing into the wind faster).

There becomes a point when the "piss cloud" upwind of the prop is so effective that the cart is moving at the same speed as the wind ie the piss cloud is sufficiently large and that it decellerates the passing wind enough to maintain momentum (the wind's momentum is transferred to the cart) by overcoming friction.

There's no reason why it should stop there though. It's not about energy. The cart can decellerate a couple of tons of air from 10 knots to nothing with its prop.. meaning that the cart can have all that energy as speed (and the cart weighs less than 2 tons!).

So the cart carries on pushing wind backwards.

If you were to set up a smoke machine on the cart, then you would see a huge turbulent flow of air blowing back from the cart... still moving forward relative to the ground though.....

So, if the cart can create a sufficiently obstructive "back piss" that it can push on then it can indeed go faster than the wind...