Bensen Gyro-Copter B-8M

Bensen Aircraft Corp.

First Flight July 8, 1957

Single place

Single seat

Acquisition Source: "Red" Smith

Russian‑born Igor Bensen was a leading proponent of the lightweight, home‑built rotor­craft. After working for many years with General Electric and later with the Kaman Aircraft Corporation on rotorcraft research, he formed the Bensen Aircraft Corporation in 1953. Its first product was the single ­seat, ramjet‑powered Mid‑jet, tested in 1954, and this was followed in 1955 by the B‑4 Sky‑Scooter which was powered by a 40 h.p. Nelson engine and could carry a pilot and one passenger.

The B‑5 Gyro‑Glider of 1954, a single‑seat rotor‑kite towed into the air at around 20 m.p.h. (30 km/hr.), obtained lift by the flow of air over its rotor. From this factory‑built prototype, Bensen evolved the B‑6 and B‑7, and from these came a standard produc­tion model the B‑8, available as a factory‑built machine or in kit form for amateur construction.

Powered autogyro versions of the auto‑kites also were developed. The first of these, the B‑7M (M=motorized), flew for the first time on December 6, 1955. The B‑8M first flew on July 8, 1957. The B‑8M normally was powered by a 72 h.p. McCulloch piston engine. Optional features included a 90 h.p. McCul­loch engine and a mechanical rotor drive. By engaging this drive, the rotor can be accelerated to flying speed while the aircraft is stationary. Then, by transferring the power to the pusher propeller, it is possible to take off in only 50 feet of runway rather than the normal 300 feet for the unpowered rotor drive.

Variants of the B‑8M included the B‑8MA Agri‑Copter for agricultural spray, and two water‑borne ver­sions, the B‑8B Gyro‑Boat with a boat‑type hull and twin outrigged stabilizing floats, and the B‑8W Hydro‑Glider mounted on twin floats. Bensen also developed a multi‑engined ver­sion of the B‑8M known as the B‑11.

Aircraft Specifications

Rotor Diameter: 
20 ft.
Fuselage Length: 
11 ft. 4 in.
Maximum Speed: 
85 mph
Cruise Speed: 
60 mph
6 ft. 3 in.
Empty Weight: 
247 lbs.
Gross Weight: 
500 lbs.
72 hp McCulloch 4318E