Wind powered helicopter
There are plenty of remote controlled helicopters in the market, and I bet that 99% use some kind of batteries but that is not the case with this helicopter, all thanks to the nature and the power of the wind.
Of course that if you want to have a good flying experience with this special copter the wind speed can't be anything below 20kmh. You must also take in consideration that the limit in terms of highest level is close to 100 meters, or else you might lose the Wind Powered Helicopter forever.
To launch, just give the rotor blades a spin, then with your back to the wind, hang the copter at arms length, once the rotor blades start to spin, step back against the wind slowly releasing the string.
Source: crazyaboutgadgets.comAdded: 23 April 2007