B-8M Gyrocopter

Designation: X-25 (Air Force)
Version: B-8M
Nickname: Gyro-Copter, Gyro, Autogyro
Type: a push-propeller aircraft using a wind-powered propeller for
Length: 11 ft.  4 in.  
Height: 6 ft. 3 in.  
Rotor Diameter 21 ft. 6 in.  
Cost: approx $2000  
Gross Weight, max 550 lbs.  
Gross Weight, empty: 247 lbs. empty  
No. of Engines: 1
Powerplant: McCulloch 4318 piston engine
Horsepower (each): 72 hp (diff options ranged 65 to 90 hp)
Range: 84 miles in 1 hour and 25 minutes  
Cruise Speed: 65 mph    
Max Speed: 95 mph    
Ceiling: 15,000 Ft  


The Bensen B-8M gyro-copter is motorized version of the Bensen B-7, a small
single-seat gyro-glider developed in the mid-1950s by aviation pioneer Igor
Bensen. A Russian immigrant to the United States, Bensen designed the B-8M as a
light, safe rotary-wing aircraft for private use. Little more than a rotor,
seat, tailfin and motor the B-8M's simple design could be assembled from a kit
by aviation hobbyists in less than forty hours using simple hand tools.

Gyro-copters are a helicopter-airplane hybrid, like a helicopter the
gyro-copter is dependent on its rotor blade to create and maintain lift. Unlike
a helicopter, the gyro-copter's rotor blades are unpowered; therefore, the
aircraft requires a short roll before taking-off.

High aircrew loss rates during the height of the Vietnam War spurred the US
Air Force to acquire a number of B-8Ms for training and evaluation giving the
aircraft the designation X-25A. As a part of the Discretionary Descent Vehicle
program, an attempt was made to integrate gyro-copter features into ejection
seats and provide aircrews with the ability to maneuver after ejection in hopes
of increasing survivability and evading capture. Tests proved promising however,
with the end of the war, loss rates decreased and the DDV program was canceled.

The museum's Benson B-8M was donated on January 19, 1991, by Adeline Weigandt
of Huntington Beach, CA. This aircraft is on loan from the USAF.