Aviation of World War II

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.

A military series of 10 vehicles was produced at plant number 39 in 1936. The lead vehicle of the military series was transferred to the Air Force in June 1936.

In 1937, factories # 1 and # 81 produced 61 and 51 DI-6, respectively. The following year, Plant No. 81 produced the last 100 aircraft. In total, 222 aircraft were produced at three factories in 1936-38.

On October 1, 1937, there were 28 DI-6s in the Air Force units. In October 1938, the 52nd Omsk Attack Air Brigade had 29 DI-6SH. In October 1938, the BOVO Air Force - 14th ShAP of the 114th Gomel Attack Air Brigade had 60 DI-6Sh aircraft, of which 6 were faulty. According to the approved staff of the Red Army Air Force on January 1, 1939, it was planned to keep in service 60 DI-6I in fighter aircraft and 64 DI-6SH in assault aviation.

In 1939, the gradual displacement of the DI-6 from combat units to training and reconnaissance units began. By the fall of 1939, many squadrons armed with DI-6 began to retrain on the I-15 bis. After two years of operation of the DI-6 in the Kiev Special Military District in the summer of 1939, they came to the conclusion that it would be more expedient to use them as scouts, which was done during the military campaign in Poland.

Photo	Description
	Drawing TsKB-11

On August 4, 1935, the Decree of the Council of Labor and Defense No. S-96 "About redesigning the Di-6 for an attack aircraft" with the following data: maximum flight speed near the ground - 340-350 km / h (at an altitude of 3000 m - 390-400 km / h), landing speed - 90-95 km / h, range - 400-500 km. Armament, six normal caliber forward-firing machine guns, one defensive machine gun and 80 kg of bombs.

The resolution of the STO obliged the GUAP (namely, plant No. 39) to manufacture this machine within a month and a half. At the same time, the first copy of the DI-6Sh was allowed to be built without armor and the issue of installing it was decided after testing the prototype.

In addition, the GUAP was supposed to speed up the preparation of the production of the DI-6Sh attack aircraft at the plant No. 81, in order to ensure their serial production from the beginning of 1936.

In the period from October 31 to November 19, 1935, joint factory and field tests were carried out on the first copy of the light high-speed attack aircraft DI-6Sh M-25 (TsKB-38), produced at the Central Design Bureau of Plant No. 39 department V.P. Yatsenko under the general leadership of the head of the brigade (or KB-1) S.A. Kocherigin.

The aircraft was a modification of the two-seat Di-6 fighter, made according to the scheme of a single-column polutoraplan with a landing gear retractable into the center section of the lower wing with original brake wheels with internal shock absorption.

The DI-6Sh had an armored backrest and pilot's seat cup.

Offensive armament consisted of two synchronous PV-1 machine guns, four PV-1 machine guns mounted under the lower wing in special fairings at an angle of 2 ° 17 "to the longitudinal axis of the aircraft with an ammunition capacity of 3000 (4000 overload) rounds and a bomb load of up to 80 kg ( 8-10 kg bombs, 4 under the wing and 4 under the fuselage).

For defense against enemy fighter attacks from the rear hemisphere, ShKAS (ammunition load of 750 rounds) served on a pivot mount at the shooter.

With a flight weight of 2115 kg, the aircraft developed a speed near the ground of 305 km / h, and at an altitude of 3000 m - 358 km / h. The climb time of 5000 m was 17.5 minutes.

In eight flights, small arms were tested, in three - bombs and in two - chemical weapons.

Wing machine-gun batteries worked normally. Machine gun control and aiming is convenient Shooting was carried out from a height of 10-15 m.

The target was a company of infantry in marching order Plywood "soldiers" were placed on an area of ​​20x100 m, 80% of which were hit as a result of the DI-6Sh attack. At the same time, about 20% of the total number of fired bullets hit the targets.

In general, the shooting results were considered good. However, it was noted that at altitudes above 17 m "shooting is not provided" due to unsatisfactory forward-downward visibility.

Bomb and chemical weapons have never failed during the entire period of testing. But military pilots noted that the weight of the bomb load and the range of bombs did not correspond to tactical tasks and severely limited the combat capabilities of the machine as an attack aircraft.

In addition, the control of an attack aircraft near the ground, especially at high speeds, was difficult and tiring for the pilot (the aircraft pitched heavily, the pressure on the control stick was high).

The latter made it very difficult for the pilot to conduct a detailed orientation to reach the target and did not allow targeted bombing. The navigator, due to the lack of the necessary visibility, could not help the commander in any way.

Despite the presence of a number of obvious shortcomings, the DI-6Sh was accepted for serial construction and was produced in small quantities from the end of 1936 at the aircraft factory No. 1 (61 copies).

In addition, in the combat units, as the Di-6 fighters were removed from service, the latter were converted by the forces of the engineering and technical staff of the units into assault variants.

In the summer of 1938, the DI-6Sh studied the modes of bombing from a dive at angles of 40-90 °

It was recommended to enter into a dive from a height of at least 2500 m, the permissible overload at the output is 3.5-6 at a speed not exceeding 450 km/h. In this case, over the entire range of angles, the attack aircraft dived steadily, had no tendency to drag at large angles, and was sensitive to rudder deviations. No vibrations of the tail and wings were observed during the dive.

After a comprehensive analysis of the capabilities of the DI-6Sh and the conditions of modern battles, military experts concluded that these aircraft could only be used as training aircraft at the first stage of training the flight crew of combat units for dive bombing.

The bomb load of 40 kg, as well as the impossibility of hanging large-caliber air bombs on the DI-6Sh, made it almost pointless to dive bomb in combat conditions.

As a result, the DI-6Sh was gradually transferred to the category of training for assault units.

Thus, despite the enormous efforts of the country, the combat units of the assault aviation of the Red Army by the end of the 30s were in a state of "protracted" crisis.

Inspection of the assault air units of the Red Army, carried out by the Air Force command in the first half of November 1938 (at that time the Air Force had 12 full-time assault air regiments), showed their extremely low combat capability

The attack aviation regiments were armed with a variety of materiel, the combat qualities of which were characterized by a high commission as inadequate to the requirements of modern warfare and the tactics of the combat use of attack aircraft.

In particular, it was noted that the DI-6Sh aircraft for strafing strikes, due to poor forward-downward visibility, is completely unsuitable.

The flight performance of the combat vehicles of the regiments did not correspond to the modern development of aviation.

Of the 561 aircraft that were in service with ground attack aviation regiments, there were 200 R-5 aircraft, R-5Sh - 82 aircraft, R-5SSS - 174 aircraft, DI-6Sh attack aircraft - 60 aircraft, R-6 - 31 pcs. and SB - 14 machines (the latter were used as auxiliary and for training flight crews).

• The history of aircraft designs in the USSR, 1938-1950. / V.B. Shavrov /
• Fighter DI-6 / KR Ivnamin Sultanov /
• Lost in the ranks / KR Nikolay Soiko /

The first in our country two-seat fighters DI-1 and DI-2 were developed under the leadership of N.N. Polikarpov in the second half of the 1920s at the Moscow aircraft plant No.1. Then this work was continued at the Central Design Bureau of the Aviarabotnik plant named after Menzhinsky. In the summer of 1931, a mixed-design biplane DI-3 was built there, and at the beginning of 1933 a strut-braced all-metal high-wing DI-4 by the French designer A. Lavil. All of them became prototypes. A logical continuation of this direction in the Central Design Bureau of the Aviarabotnik plant was the creation by the brigade of S.A. Kocherigin in the summer of 1934 two-seat biplane TsKB-11 or DI-6. The aircraft designer V.P. Yatsenko. Behind the shoulders of a recent graduate of the Moscow Aviation Institute, there was a great life and professional experience. After graduating from the Kursk real school in 1915, Vladimir Panfilovich served in the army as an aircraft mechanic and mechanic, worked as a designer at V.V. Slyusarenko, A.A. Porokhovshchikova and Yu.A. Möller. Since 1924, at the plant No.1 under the leadership of N.N. Polikarpova Yatsenko designed the fuselages of the I-3, DI-2, U-2, TB-2 and R-5 aircraft.
In October 1929, he was appointed a leading designer at the Central Design Bureau of Plant No.39. In the fall of 1931, Yatsenko headed the newly formed design group of two-seat fighters TsKB-TsAGI, which worked at the TsAGI experimental design plant. The next year, after another structural restructuring of the experimental aircraft construction, the V.P. Yatsenko was attached to the brigade of attack aircraft and scouts of Sergei Alekseevich Kocherigin at plant No.39.