Wind Powered Quad-Cart

I haven't seen anything this on here so I thought I'd step up. Engineers (or anyone who fancies themselves A DIYer) I found a few days back I little some very interesting Wind Powered Rides...
six-or-seven-ways-wind-powers-vehicles OK so we know it CAN be done, but can it be done by a DIYer?
OK here's my concept, Design and shape are optional but basic components are such: Take a pair of multi-speed Bicycles, their gearing will be the basic propulsion for this vehicle. Take one of the "bikes" and hook up a prop where the pedals "where" and set the wheel output to be higher then the prop speed, this should take care of the foreward movement once going.
Now for the initial starting power (Bike 2), this can either be by petal, or by electric (solar/battery- up to you) But the basis for this whole thing is simple energy transfer, if the moving air over the prop causes the drive wheels to go, and by having them geared higher, the vehicle SHOULD move faster the faster you go ..Right?
Can I get some math to back this up? it sounds like it would work.

Picture of Wind Powered Quad-Cart
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yourcat8 years ago
With this particular design, you won't be able to go any faster than the current wind speed when you have the wind behind you, you won't be able to go at all with the wind beside you, and with the wind in front you'll have a LOT of aerodynamic drag. I like a design with an adjust able-angle sail, not a mechanical drive.
yourcat yourcat8 years ago
Wait, I didn't look at all the pictures before posting that, the one in the second picture is actually pretty good.
Green_Primus (author)  yourcat8 years ago
Thanx glad to see some interest in this idea. Now I'm not to great with Math/ drag/ angle of attack/ etc.. But say you use the design in the second Picture (Vertical Axis) does prop angle effect its speed? Logic sound like it would, but does this mean some angle would work better then others?
To your question, what ever you do with a turbine like that you can't go faster than the wind speed. That's why I like sails.
See this...
Wind powered cart goes downwind 2.5X wind speed
Sure it sounds impossible, but you can't argue with a real demonstration.  The explanation of how it works is kind of like a sailboat (which can go faster than the wind) with the propeller blades acting as the sails, but constrained to spin in a circle instead of travelling in a straight line.
You can also imagine a cart which has wheels on top and bottom and a moving platform above it.  You can connect gears between the top wheels and the bottom wheels so that the movement of the upper platform rotates the bottom wheels and makes the cart move.  By adjusting the gear ratios the cart can move faster than the upper platform.  It's a little harder to grab moving air, but the principle is the same, the cart can be made to move faster than the moving air.
I want to see a design like the one in the second picture, but with hinges on the leading edge of each blade, so that as a blade is on the side where it is picking up the wind, it flips out to a high angle where it can pick up the most wind, but when it is going back upwind it stays in a position with the least amount of unnecessary drag. Also, I'd like to see it slowly charging a small Li-Po battery pack, so you could give it a little extra power through an electric motor when you needed it.
NachoMahma8 years ago
. I'm confused as to what the objective is. . Your forward speed doesn't gain you anything - it's actually a loss - so wouldn't a sail work better and have fewer moving parts? . The spinning parts do have a high cool factor.