Unlike traditional helicopters the GEN H-4 has 2 sets of coaxial, contra-rotating rotors (like a KA-52 Hokum) which eliminates the need of a tail rotor for balancing. It is powered by 4 lightweight 125cc 2 cylinder engines which use standard gasoline. It can fly to an altitude of 1000 meters at a top speed of 59 mph for up to 30 minutes.
The blog of a Leslie Wong