Here is another link for the Fa 330.
http://en.wikipedia.org/wiki/****e_Achgelis_Fa_330
Technically, they are not helicopters, but gyro-gliders. They do not have a power source of themselves to power the rotor. Power was gained by towing the craft by the uboat, and the air flowing through the rotor disk/blades spinned up the rotor and was enough to maintain lift up. So they couldn't lift up straight vertically from the spot. An 'auto-gyro' does have a power source, but it is only providing forward thrust like a propellor aircraft does. (so avoiding the need for a towboat
) The lifting power also comes from the air flowing through the rotor disk. The rotating blades create the same lifting effect as ordinary fixed wings. So it neither lifts up vertically from the spot. It's more like a STOL (short take-off or Landing) type aircraft.
The aircraft in the image jimbuna posted appearantly is a (dual rotor) helicopter that was self powered. I thought helicopters were only succesfully developed after WW2. Oh well, history lesson learned.
