Only a single prototype had been built before the program was terminated upon the death of Nikolai Nikolaevich Polikarpov, the head of the aircraft's design bureau, in 1944.

The fuselage was built of 'shpon', molded birch plywood, 4–5 mm (0.16–0.20 in) thick and was reinforced with a welded steel tube framework and a network of bracing wires in the midsection around the aperture for the wing and the capacious bomb bay.

The duralumin slotted flaps were electrically powered and ran the length of the wing center section, divided by the engine nacelles.

[3] The bombardier was given an extensively glazed position in the nose which also had a fixed 12.7 mm (0.50 in) Berezin UB machine gun for which the pilot had a reflector sight.

Its performance promised to be outstanding, but Polikarpov's death a month earlier caused his design bureau to be shut down and all his projects were terminated.