Compact Single-Seater Helicopter GEN H-4 (Video)
GEN H-4 is the world’s smallest co-axial helicopter. This ultra-light aircraft weighs only 155 lbs (70kg) when empty, and is capable of reaching a maximum speed of 55 mph (88 km/h). The GEN H-4 is powered by four twin cylinder engines feeding into a central transmission, with two sets of rotors turning in opposite directions. The GEN H-4 can sustain flight even if one of the engines malfunctions, as the remaining three engines are strong enough. This one-man helicopter was designed by the President of Engineering System Co. Japan, Mr. Gennai Yanagisawa. It is currently being manufactured and sold in a kit form in Japan, for a price of approximately $30,000 per kit.
The GEN H-4 was first flown in 1998, and reportedly is quite easy to operate. The pilot controls the helicopter’s rise and descent by pushing the throttle lever. One can choose to fly in a certain direction by simply pulling or moving the control bar in the opposite direction. In order to turn to the right or to the left, one has to push the yaw-control-switch.
The frame of the GEN H-4 is made of two-inch aluminum pipes. Located in front of the pilot is the control pod with the throttle, tachometer, main switch, starter switch and yaw switch. Four GEN125 engines power this helicopter. Each is a 10hp, 125cc, two stroke, two horizontally opposing cylinders, air cooled electric start engine, equipped with independent ignition, carburetors, starter switch and centrifugal clutches. Each of the four engines is connected to the transmission through a centrifugal clutch so that if one of the engines stops working, it is overridden by the other three engines and the flight continues.
The lightweight transmission consists of cast aluminum upper and lower cases with a total of 27 precision ground, with heat-treated gears sandwiched in between.Two rotors travel in opposite directions, keeping the helicopter stable by counteracting each other’s torque, so that there is no need for a tail rotor. Yaw is controlled through a differential gear within the transmission, driven by an electric motor. The fuel type required is a 30:1 mixture of automobile gasoline and two stroke oil.
To insure safety, a ballistic parachute is provided above the mast. In addition, it is possible to perform a safe emergency landing on two engines. Plans for future developments include installing an automatic altitude controller, adding under seat air bags, and designing the one-man helicopter in such a way that will enable folding it, making it easier to carry from one place to another.
TFOT recently covered several other innovative aircrafts, including the Individual Lifting Vehicle (ILV) concept that is being developed as a kit in the United States, the Gyrocopter – a new flying motorcycle currently under development by the Dutch company PAL-V, and Moller’s M400 Skycar – a concept vehicle that can execute vertical take-off and landing (VTOL) like a helicopter, fly like an airplane and drive for short distances on the ground like a car.
More information about the GEN H-4 can be found on the company’s website.