Aerotechnik WGM.21

The Aerotechnik WGM.21 is a quadrotor helicopter that was developed in the 1970s.
Design and development.
The WGM.21 is an open cockpit quadrotor. Four rotors are mounted at the end of a four tubular supports arranged into a X shape. Cyclic and collective controls are mixed into a single control yoke. Pitch is controlled by foot pedals. A second model, the WGM.22, was developed with side-by-side configuration seating and an enclosed cockpit.