DI-6 (Two-seat fighter). The aircraft was a mixed-design one-and-a-half-plane with retractable landing gear, equipped with an M-25 nine-cylinder air-cooled engine. The wing box consisted of upper and lower center sections, two pairs of consoles and X-shaped struts and ribbons. Both wings are of two-spar wooden structure with canvas sheathing. Slotted ailerons with a duralumin set and linen sheathing are suspended at the ends of the upper wing only behind the struts. In the center section of the upper wing there were two gas tanks of 76 liters each. The relative thickness of the center section profile decreased towards the middle. The center section is attached to the fuselage with two N-shaped brackets made of chrome-molybdenum pipes.
Fuselage - welded truss made of chrome-molybdenum pipes. Rigid spatial truss was pivotally connected to the engine and the lower center section. Duralumin formwork is fixed on the farm for fastening the cladding: the front part to the pilot's seat is duralumin, then linen. The cockpit is of an open type with a protective visor made of triplex glass. Seat, adjustable for the height of the pilot on the ground.
Closed on three sides with celluloid glazing, the arrow's cockpit had one triplex window on each side. The shooter had two seats. The main one - facing the tail, connected kinematically with the arc carrying the pivot shooting installation with the ShKAS machine gun, and the additional one, reclining from the starboard side, which made it possible to sit facing in the direction of flight. The cockpit fairing of the arrow consisted of two halves, connected by a lock along the longitudinal axis of the aircraft and dropped in an emergency. The left half was reclined when the shooter got into the cockpit.
Control - single, normal with wire rope. The pedals were adjusted for the height of the pilot.
Single fin tail unit with fixed stabilizer. Stabilizer and elevators with a duralumin power frame and linen sheathing. Elevators with axial compensation. The keel consisted of an all-metal bottom (a stabilizer was attached to it) and an upper part with a duralumin frame and linen sheathing. Rudder without compensation with duralumin frame and linen sheathing.
The retractable chassis was equipped with 750 × 125 mm brake wheels with oil-pneumatic internal shock absorption. Cleaning was carried out with a rigid compressed air device. The lifting device had a mechanical emergency manual drive for landing gear. Tail crutch uncontrollable with oil-pneumatic shock absorption.
First flight on September 30, 1934. In the fall of 1937, during state tests of serial aircraft No.81034 (photo above), the range was determined with a take-off weight of 2033 kg, a fuel supply of 162 kg (the remainder of 15 kg). In particular, at an altitude of 1020 m at a speed of 220 km / h, it was 460 km, and at 5750 m at a speed of 250 km / h - 517 km. As before, communication left much to be desired, both with the ground and between the crew members. The test report also noted the insufficient efficiency of the ailerons at speeds less than 200 km / h, the fire hazard of the gas tank drain prompter near the exhaust pipe of the upper engine cylinders, the open location of the control cables in the rear cab.
In December 1937, pilot Nikashin with test lettuer Sokolov completed state tests of the improved serial DI-6M-25V (No.81024), which was distinguished by the M-25V engine with a takeoff power of 775 hp, lowered horizontal tail, increased by 0.254 m & # 178; aileron area, sound signaling of landing gear retraction and release. The control of the wheel brakes was transferred to the aircraft control stick, the power supply units for wing-mounted machine guns of the plant No.81 design were used and the upper center section tanks were strengthened. As a result of the downward displacement, the rigidity increased and the vibration amplitude of the horizontal tail decreased. Its efficiency increased during takeoff: the plane began to easily tear off its tail at the beginning of the takeoff run. It has become more convenient to control the wheel brakes from the aircraft control stick than from the pedals.