Rotor kite

Like an autogyro or helicopter, it relies on lift created by one or more sets of rotors in order to fly.

[citation needed] Research into rotor kites or gyrokites was deepened during World War II, and one type in particular, the Focke Achgelis Fa 330, reached active service, being towed behind German U-boats as an aerial observation platform.

These were marketed as plans or kits for building at home, beginning with the B-5 and culminating with the B-8 by the end of the decade.

The Bensen designs became so ubiquitous that the term "gyroglider" is sometimes used to refer to any rotor kite, regardless of manufacturer.

In the 1960s, a B-8 gyroglider was evaluated by the United States Air Force as a "Discretionary Descent Vehicle", to provide a more controllable alternative than a parachute for a pilot ejecting from a stricken aircraft.