The GEN H-4 is a device that fulfills the promise of a personal jetpack, although it's technically a helicopter. In fact the GEN H-4 is officially recognized as the world's smallest piloted helicopter and it's available for purchase now.

A rarity amongst jetpacks, the GEN H-4 really is for sale, albeit in kit form (30-40 hours of assembly required) for US$59,500 from Ace Craft USA. Credit for the design and development of the GEN H-4 belongs to GEN Corporation, Japan.

Performance

The GEN H-4 has a respectable speed of 55 mph (100 km/h) and an estimated maximum altitude of 10,000 ft (3,000m). It even has a reasonable flight duration of up to 60 minutes (dependent on the pilot's weight), compared with a typical jetpack flight lasting up to 1 minute at best.

Control

The co-axial, counter-rotating rotors on the GEN H-4 means it doesn't need a tail rotor to counter the torque of the main rotor. Control while in flight (Flight dynamics) is achieved as follows:

• Roll and pitch control is provided by a control bar that pivots the rotor head directly, analogous to the control bar on a hang glider
• Yaw control is provided by varying the relative speed of the counter-rotating rotors
• Altitude control is provided by varying the speed of the rotors using the engine throttle

While on the ground the GEN H-4's tripod-like frame transfers weight directly to the ground, avoiding excessive loads on the pilot's body. The weight-bearing ability of a pilot is usually the limiting factor in determining the takeoff weight, and therefore flight duration, of a traditional jetpack.

Safety

Like a motorcycle compared to a car, the GEN H-4 is a risky craft to fly providing little structural protection for the pilot in case of an emergency landing. Also the GEN H-4 cannot perform autorotation (glide) in case of an engine failure, unlike a traditional helicopter. To compensate, the GEN H-4 has 4 independent, high-power 2-stroke engines. An emergency landing is possible with only 2 engines working. Also an optional extra is an emergency ballistic parachute mounted clear of the rotors.

No Pilot's License Needed

The GEN H-4 is classed as a Part 103 ultralight vehicle and therefore doesn't require a pilot's license for use in the US. So for all those would-be flying daredevils with spare cash and time to assemble it, the GEN H-4 can be your very own personal helicopter - what more do you need?