Directorly Downwind Faster than the Wind

[Mike Furness]

hello 'no name', I'm not sure if you have followed this topic from the start, or what argument you seek with me?
Your statement that if there is no RELAIVE wind speed says all!
Of course, if there is substantial wind,(relative to ground) sufficient to generate power from a propellor, then it can be sufficient to provide some motive power forward, this is not in dispute

In case you have 'lost the plot,' the disputed claim is that in 'still air', when you have accellerated the vehicle to a given velocity, sufficient energy exists in the wind such that the vehicle can continue to run, and indeed go faster from it's own generated wind.

Mike.

Mike.J. Furness

[Subduction Zone]

Mike, I think I have followed this argument far longer than you have, and you seem not to understand how it works.  First off it is not over unity or perpetual motion in any way.  It runs off of the power of the wind and if the wind is not blowing the cart does not work. 

Lets first define wind before I go any further.  Wind in this case is the actual movement of the air over the ground, not the apparent wind that an observer on the vehicle feels.  Even when the vehicle is moving at the velocity of the wind the actual wind is still moving over the ground and is a potential source of energy.

Now how does the cart work?  The wind does not directly turn the propeller, in fact if you lifted the wheels off of the ground the propeller would rotate in the opposite direction that it does when running.  At very low speeds it works on bluff body forces, the wind hits the body of the cart and the prop and pushes it in the same manner that a square rigged sail works.  As the cart moves forward the wheels turn the propeller which adds thrust to the cart.  If you compared it to a sail boat it would be very similar to a boat sailing on a downwind reach.  In fact if you unspiral the path that the propeller takes you would see that it is in the form of a downwind reach.  No good sailor denies that a boat, especially an ice boat or land yacht, cannot beat the wind by sailing downwind and jibing back and forth.  It is very counterintuitive, but it breaks no laws of physics. 

[Subduction Zone]

I have looked at quite a few posts here and even those who believe that it works very often have it wrong.   There is nothing any more revolutionary to this concept than that of a boat sailing either into the wind by tacking or by sailing with a velocity made good greater than wind speed directly downwind by jibing.  The prop only allows the vehicle to do this in a straight line.  In both of those cases sailboats slow the speed of the air that they interact with relative to the ground.  The same with the cart.  It slows down the speed of the air that it interacts with relative to the ground.  That is why it only works when the real wind is blowing over the ground.  If the air is not moving over the ground there is no energy to gain by slowing it down.

Mike your idea of modeling the cart at wind speed by using a stationary car on a windless day is flawed because the air is not moving over the ground.  A much better way to do it would be to put the cart on a conveyor belt, or even a treadmill.  By a simple Galilean Transformation you can see that the cart would react the same on the treadmill on a day where the speed of the wind was the speed of the treadmill. If it moved forward on the treadmill it would move faster than the wind on  the road.

[quarktoo]

What about friction or traction.

You are converting the speed of the wind and the torque of the larger propeller into traction on the wheel or propeller.

There is a video of the boat on youtube somewhere and it is patented. It would not make a god boat or a good car - non-starter.

[Subduction Zone]

What?  Forget about the torque.  You are converting the speed of the wind into energy going into the cart.