Aircraft Cooperative Mechta Russia AC-4 
Avia Stroitel AC4

A runner up in the OSTIV world class sailplane design contest in Oerlinghausen in 1993, the AC-4 went into production following modifications that had been recommended by the Organisation Scientifique du Vol a Voile (OSTIV). The Russia comes in the taildragger AC-4A model, and the AC-4B with main wheel set behind the center of gravity and a nose wheel. The latter has a slightly more spacious cockpit able to accept taller pilots. The AC-4 is offered with a ballistic emergency recovery parachute. It can be fitted with a 12 bhp / 9 kW McCulloch MC-101B 2 cycle sustainer engine.
The first flight of the AC-5m was in December 1999.
Designed by Vladimir Federov.

Wing Span: 12.6 m / 41.3 ft             
Wing Area: 7.7 sq.m / 82.9 sq.ft
Empty Weight: 130 kg /286 lb.            
Payload: 120 kg /265 lb.
Gross Weight: 250 kg / 551 lb.             
Wing Load: 32.46 kg/sq.m / 6.66 lb/sq.ft
Aspect ratio: 20.5                 
L/D Max: 31 @ 83 kph / 45 kt / 52 mph
MinSink: 0.66 m/s / 2.16 fps / 1.28 kt     
Airfoil: Wortmann FX-60-157
Structure: GFRP/ epoxy             
Seats: 1

AC-4A - Single seat, Mid wing, Composite, Tailwheel, Sailplane
AC-4B - Single seat, Mid wing, Composite, Nosewheel, Sailplane
AC-4C - Single seat, Mid wing, Composite, Retractable tailwheel, Sailplane