Russian military were thinking about a attack aircraft. Two proposals were offered with a strong reinforced heavy fighter. They added guns and racks for bombs/rockets. One other proposal of MAI was this tandemwing designed by Pyotr Dmitrievich Grushin. Due to the tandemwing, which allowed a more rearward CG, they could mount a turret in the rear. The rear wing took 45% of the lift.
First prototype was a single seater and didn't have the turret yet.
Second prototype was a two-seater with the canopy more backwards and the turret installed.
The lack of a rudder in the view of the turret made a nearly 360° firing range of the turret possible.
Both wings were having ailerons and elevators.
The rudder was installed under the rear wing.
Flight behavior changed towards bad. Longintutal stability became bad at higher speeds, rudder response was poor and take off was too long. Also the turret decreased the speed with 34 km/h (21 mph). A more conical turret was suggested and the front wing and landing gear needed to be tougher.
Later a rudder variant above and below the rear wing was choosen for the third prototype.
It had improvements but interest was gone and the project got cancelled.
Three prototypes flew between 1937 and 1939, but no production was started.
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General characteristics
Crew: 2
Length: 8.5 m (27 ft 11 in)
Wingspan: 11 m (36 ft 1 in)
Wing area: 30.4 m2 (327 sq ft)
Gross weight: 2,560 kg (5,644 lb)
Powerplant: 1 × Tumansky M-87 air-cooled radial engine, 690 kW (930 hp)
Propellers: 3-bladed
Length: 8.5 m (27 ft 11 in)
Wingspan: 11 m (36 ft 1 in)
Wing area: 30.4 m2 (327 sq ft)
Gross weight: 2,560 kg (5,644 lb)
Powerplant: 1 × Tumansky M-87 air-cooled radial engine, 690 kW (930 hp)
Propellers: 3-bladed
Performance
Cruise speed: 488 km/h (303 mph, 263 kn)
Wing loading: 84 kg/m2 (17 lb/sq ft)
Wing loading: 84 kg/m2 (17 lb/sq ft)
Armament
5 x ShKAS machine guns
200 kg bombs
200 kg bombs
This video has video of a game but it tells the story about this airplane very good.