NACA cowling
The aircraft had a metal monocoque fuselage, while the wings were of corrugated metal construction. The mainwheels of the conventional landing gear retracted backwards into the wing, being operated by cables driven by a handwheel turned by the pilot. The first prototype was powered by an imported 433 kW (580 hp) Bristol Mercury radial engine enclosed by an NACA cowling and driving a two-bladed wooden propeller. It was armed with a single PV-1 machine gun, with provision for two Kurchevsky APK-37 recoilless autocannon under the wing.