The Sukhoi Su-6 was a

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

ground-attack aircraft An attack aircraft, strike aircraft, or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision than bombers, and is prepared to encounter strong low-level air defenses while pres ...

developed during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. The mixed-power (rocket and piston engines) high-altitude interceptor Su-7 was based on the single-seat Su-6 prototype.

Design and development

Development of the Su-6 began in 1939, when the Sukhoi design bureau began work on a single-seat armoured ground-attack aircraft. An order for two prototypes was placed on 4 March 1940, and on 1 March 1941 flight testing of the first prototype was begun by test pilot A.I. Kokin. The flight tests indicated that the Su-6 was superior to the

Ilyushin Il-2 The Ilyushin Il-2 ( Russian: Илью́шин Ил-2) is a ground-attack plane that was produced by the Soviet Union in large numbers during the Second World War. The word ''shturmovík'' (Cyrillic: штурмовик), the generic Russian term ...

in nearly all performance categories, however its engine exceeded its age limit before testing could be completed, and no further

Shvetsov M-71 The Shvetsov M-71 was a Soviet radial engine built in small numbers during World War II. It was derived from the Shvetsov M-25, which was a license-built copy of the American Wright R-1820-F3 Cyclone engine. Development The M-71 was developed ...

engines were available. The second prototype flew only in January 1942 because the OKB had to be evacuated after the start of the

Great Patriotic War The Eastern Front, also known as the Great Patriotic War (term), Great Patriotic War in the Soviet Union and its successor states, and the German–Soviet War in modern Germany and Ukraine, was a Theater (warfare), theatre of World War II ...

. It was armed with two 23 mm cannon, four machine guns and ten rails for aerial rockets. Test results were very favorable, and the AFRA Scientific Research Institute recommended the acquisition of a small production batch for testing under front-line conditions. A draft resolution for the production of 25 aircraft was prepared, however unfortunately for Sukhoi, it was never officially issued. Meanwhile, combat experience with single-seat Il-2s demonstrated the need for a rear gunner. The third prototype was therefore designed with the second crewman at the expense of bomb load (decreased from 400 kg/881 lb to 200 kg/440 lb), and was fitted with a more powerful M-71F engine. Official tests revealed that the two-seat Su-6 had a 100 km/h (54 kn, 62 mph) greater top speed than the Il-2, although with a considerably smaller payload. When the troublesome M-71 was canceled, Sukhoi was directed to utilize the liquid-cooled

Mikulin AM-42 The Mikulin AM-42 was a 1940s Soviet aircraft piston engine designed by Alexander Mikulin. Representing a high-output version of the AM-38F, the AM-42 was used in the Ilyushin Il-1 fighter, and the Il-8 and Il-10 ground attack aircraft. Des ...

engine. When flight tests began on 22 February 1944, the re-engined Su-6 proved inferior to the

Ilyushin Il-10 The Ilyushin Il-10 (Cyrillic Илью́шин Ил-10, NATO reporting name: "Beast"Gunston 1995, p.108.) is a Soviet ground attack aircraft developed at the end of World War II by the Ilyushin construction bureau. It was also license-built in Cz ...

using the same engine thanks to the additional 250 kg (551 lb) of armor required to protect the liquid-cooled engine and the lower power output of the AM-42 compared with M-71F. Although the Su-6 never entered production, in 1943 Pavel Sukhoi was awarded the Stalin Prize of the 1st Degree for the development of the aircraft.

Su-7

As an experiment, the basic single-seat Su-6 design was converted into a mixed-power high-altitude interceptor named Su-7 (the name was reused in the 1950s for a supersonic fighter-bomber). The armor was removed and the fuselage was of all-metal construction. Power came from a

Shvetsov ASh-82 The Shvetsov ASh-82 (M-82) is a Soviet 14-cylinder, two-row, air-cooled radial aircraft engine developed from the Shvetsov M-62, which in turn was the result of development of the M-25, a licensed version of the Wright R-1820 Cyclone. Design ...

FN piston engine with two TK-3

turbocharger In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into th ...

s in the nose and a Glushko RD-1-KhZ rocket engine in the tail. The piston engine produced 1,380 kW (1,850 hp), while the rocket engine utilized

kerosene Kerosene, or paraffin, is a combustibility, combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in Aviation fuel, aviation as well as households. Its name derives from the Greek (''kērós'') meaning " ...

and

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

for fuel and generated 2.9 kN (600 lbf) of thrust for up to 4 minutes. Armament consisted of three 20 mm

ShVAK cannon The ShVAK (, "Shpitalny-Vladimirov Aviation Large-calibre") was a 20 mm autocannon used by the Soviet Union during World War II. It was designed by Boris Shpitalniy and Semyon Vladimirov and entered production in 1936. ShVAK were installed in ma ...

with 370 rounds of ammunition. The sole Su-7 was completed in 1944. Test flights demonstrated a top speed of 510 km/h (275 kn, 315 mph) at 12,000 m (39,370 ft) without the rocket motor, and 705 km/h (380 kn, 440 mph) with the rocket. In 1945, the rocket motor exploded during flight testing, killing the pilot and destroying the aircraft.

Variants

;A : The initial design for the Su-6. ;S :The second prototype with various modifications. ;SA (modified) :The SA with 2 x OKB-16 Cannon and 2x

ShKAS machine gun The ShKAS (Shpitalny-Komaritski Aviatsionny Skorostrelny, Shpitalny-Komaritski rapid fire for aircraft; Russian language, Russian: ШКАС - Шпитального-Комарицкого Авиационный Скорострельный) is a ...

s. ;S2A :The Su-6 fitted with a second cockpit with a rear-firing Berezin UBT machine gun. Testing revealed better performance and armour than the

Il-2 The Ilyushin Il-2 (Russian language, Russian: Илью́шин Ил-2) is a Ground attack aircraft, ground-attack plane that was produced by the Soviet Union in large numbers during the World War II, Second World War. The word ''shturmovík'' (C ...

, but despite recommendations, production was not carried out due to the M-71 engine not entering production.

Operators

; *

Soviet Air Force The Soviet Air Forces (, VVS SSSR; literally "Military Air Forces of the Union of Soviet Socialist Republics"; initialism VVS, sometimes referred to as the "Red Air Force") were one of the air forces of the Soviet Union. The other was the Sovie ...

Specifications (Su-6(SA) 2nd prototype)

References