Smallest helicopter

In terms of rotor length, the smallest helicopter is the GEN H-4 made by Gen Corporation (Japan) with a rotor length of only 4 m (13 ft), a weight of only 70 kg (154.32 lbs), and consisting of one seat, one landing gear and one power unit. Unlike more traditional helicopters, it has two sets of coaxial contra-rotating rotors which eliminate the need for a tail rotor for balancing. It is powered by four lightweight 125 cc, two-cylinder engines, which use standard gasoline. The GEN H-4 can fly to a maximum altitude of 1,000 m (3,280 ft) at a top speed of 90 km/hr (59 mph) for up to 30 mins. Control is excercised through a handlebar arrangement.