My appologies if this is old news to anyone on the forum (it was done in July 2010), but I just found out.

This group of people designed a wind-powered vehicle that can travel dead downwind FASTER than the wind! :wee:

2.5x faster officially (3.5x faster unofficially)

Check out this vid (It starts off slow- starts to get interesting at 1:30)




More info can be found on their website at: http://www.fasterthanthewind.org/

Thing has the pick-up of my old Chevette.

Maybe using the rail gun that I saw in yesterdays video to help get it going would be a good "mash" of technologies.

Yep- the price of going faster than wind downwind is terrible acceleration. The reason it's so slow off the line is that it is only being moved by the force of the wind acting upon it as a blunt surface (kind of like if you got in your buggy and put your arms out, hoping to get blown downwind).

To further complicate things, the big propeller on top is connected via a transmission to the wheels- so initially, the wind is attempting to turn the propeller in reverse, which means it's trying to turn the wheels in reverse too!

The forces are close to balanced, but the wind is slightly stronger so it starts to move- and it accelerates slowly until it reaches the speed of the wind (actual, not apparent). At this point the propeller no longer tries to spin backwards, but is propelled by the wheels and produces enough thrust to accelerate the vehicle to greater and greater speeds!