AEG helicopter

The AEG helicopter was an unusual German aircraft project, intended to create a portable observation post in the form of a tethered helicopter. It achieved lift by use of two contra-rotating rotors powered by an electric motor that was supplied with power from the ground. The device could be folded for transportation on the back of a truck. An observer's cabin was suspended underneath the rotor assembly, and could be blown clear by an explosive charge in case of emergency. Development commenced in 1933, but it was never put into service by the military.

The system was tested with an up to 800 metre long Very Low Frequency antenna for communication with submerged submarines. The three power feeder cables doubled as radiators for frequencies from 15 to 60 kHz.