Sukhoi Su-6

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Su-6
Su-6 second prototype, single-seater with M-71 engine
Type	Ground attack
Manufacturer	Sukhoi
Designed by	Pavel Sukhoi
Maiden flight	1 March 1941
Retired	1944
Status	Prototype only
Primary user	Soviet Air Force
Number built	3
Variants	Su-7

the Su-7 was a mixed-power fighter based on the Su-6. For the supersonic fighter-bomber see Sukhoi Su-7.

The Sukhoi Su-6 was a Soviet ground attack aircraft developed during World War II. The mixed-power (rocket and piston engines) high-altitude interceptor Su-7 was based on the single-seat Su-6 prototype.

Contents 1 History 2 Su-7 3 Specifications (Su-6 prototype 3 with M-71) 4 References 5 Related content

[edit] History

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 fight testing of the first prototype was begun by test pilot A.I. Kokin.^[1]

The flight tests indicated that the Su-6 was superior to the Ilyushin Il-2 in nearly all performance categories, however its engine exceeded its age limit before testing could be completed, and no further Shvetsov M-71 engines were available.^[1]

The second prototype flew only in January of 1942 because the OKB had to be evacuated after the start of the Great Patriotic War.^[2] 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.^[1]

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 {880 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 knots, 62 mph) greater top speed than the Il-2, although with a considerably smaller payload.^[2] When the troublesome M-71 was canceled, Sukhoi was directed to utilize the liquid-cooled Mikulin AM-42 engine. When flight tests began on 22 February 1944, the re-engined Su-6 proved inferior to the Ilyushin Il-10 using the same engine thanks to the additional 250 kg (550 lb) of armor required to protect the liquid-cooled engine and the lower power output of the AM-42 compared with M-71F.^[2]

Although Su-6 never entered production, in 1943 Pavel Sukhoi was awarded the Stalin Prize of the 1st Degree for the development of the aircraft.^[1]

[edit] 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 later reused for a supersonic fighter-bomber). The armor was removed and the fuselage was of all-metal construction. Power came from a Shvetsov ASh-82FN piston engine with two TK-3 turbochargers in the nose and a Glushko RD-1-Kh3 rocket engine in the tail. The piston engine produced 1,380 kW (1,850 hp), while the rocket engine utilized kerosene and nitric acid for fuel and generated 2.9 kN (600 lbf) of thrust for up to 4 minutes.^[2] Armament consisted of three 20 mm ShVAK cannon with 370 rounds of ammunition. The sole Su-7 was completed in 1944. Test flights demonstrated a top speed of 510 km/h (275 knots, 315 mph) at 12 000 m (39,370 ft) without the rocket motor, and 705 km/h (380 knots, 440 mph) with the rocket.^[2] In 1945, the rocket motor exploded during flight testing, killing the pilot and destroying the aircraft.^[3]

[edit] Specifications (Su-6 prototype 3 with M-71)

Data from ^[1][2]

General characteristics

• Crew: Two (pilot and gunner)
• Length: 9.24 m (30 ft 4 in)
• Wingspan: 13.50 m (44 ft 3 in)
• Height: 3.89 m (12 ft 9 in)
• Wing area: 26 m² (280 ft²)
• Empty weight: 4 000 kg (8,820 lb)
• Loaded weight: 5 534 kg (12,200 lb)
• Powerplant: 1× Shvetsov M-71F radial engine, 2,200 hp (1,620 kW)

Performance

• Maximum speed: 514 km/h (280 knots, 320 mph) at 3,800 m (12,465 ft)
• Range: 973 km (525 nm, 605 mi)
• Service ceiling: 8,100 m (26,575 ft)
• Rate of climb: 10.6 minutes to 5,000 m (16,405 ft)
• Takeoff roll: 410 m (1,345 ft)
• Landing roll: 730 m (2,395 ft)

Armament

• 2x 23 mm Nudelman N-37 cannons in wings, 90 rounds
• 2x 7.62 mm ShKAS machine guns in the wings, 1,400 rounds
• 1x 12.7 mm Berezin UBT machine gun in rear turret, 196 rounds
• Up to 200 kg (440 lb) of bombs

[edit] References

1. ^ ^{a b c d e} Sukhoi Su-6. Sukhoi Company Museum. Retrieved on January 7, 2007.
2. ^ ^{a b c d e f} Shavrov V.B. (1994). Istoriia konstruktskii samoletov v SSSR, 1938-1950 gg. (3 izd.). Mashinostroenie. ISBN 5217004770. 
3. ^ Green, W; Swanborough, G (2001). The great book of fighters. MBI Publishing. ISBN 0760311943. 

[edit] Related content

Comparable aircraft

• Il-2
• Il-10

See also