Bensen B-7W Hydro-Gyroglider

Home-built Sport Aircraft

This hydro-gyroglider was home-built and flown in 1957 and beyond from plans supplied by Igor Bensen, a leading proponent of lightweight, home built rotorcraft. A boat towed the rotor-kite into the air at 20-35 mph. The landing speed was 7 mph. The rotor speed was 350 rpm. Lift was obtained by the flow of air through the rotor.

In World War II German U-boats towed rotor-kites as aerial observation platforms.

During the 1950s, rotor kites were developed as recreational aircraft, largely due to the efforts of Igor Bensen in the United States, whose Bensen Aircraft Corporation produced a series of such aircraft, dubbed "gyrogliders" by Bensen. 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.

“We were looking for something more fun than water skiing and had read about rotor-kites, so we wrote to Igor Bensen for plans. We built the aircraft in a garage from locally purchased supplies," said builder/pilot Gene Anderson, who donated the craft.

"We had great fun flying at tree top level along the Meramec and Mississippi Rivers near St. Louis, MO. We taught ourselves to fly since little flight guidance was provided. We learned from the sound of the rotor and the feel of the controls when the rotor-kite was ready to take off. The overhead control stick worked in the opposite direction to other aircraft, so to roll right, you moved the stick to the left.

"We gradually lengthened the tow rope to around 200 feet, and the power of the rotor was able to lift the tail end of the tow boat so as to cause propeller cavitation.”

This B-7W hydro-gyroglider provides a unique example of a water-borne rotorcraft and complements the Museum’s B-8W wheeled aircraft.

Aircraft Specifications

Rotor Diameter: 
21 ft.
Fuselage Length: 
12 ft.
7 ft.
Empty Weight: 
150 lbs.
Acquisition Source: 
Donation by Gene Anderson