Backpack helicopter

Yaw is controlled by fine adjustment of a differential gear in the rotor drive transmission.

Second, the rotors are fixed pitch, which assists with simplicity; this means, however, that in the event of engine failure autorotation is impossible.

In theory, a helicopter would be more efficient than a rocket-powered jetpack, possessing a greater specific impulse, and being more suited to hovering, due to the lower velocities of the propelled gases.

[2] However, the device consists of two rotors with diameters around 3 feet (0.91 m) connected via carbon fiber tubes to a backpack with battery packs, and a pair of armrests with hand controls on them.

[3] Later video analysis revealed operator and equipment were at the end of a drop cable that was edited out using post-production software.