Suchoj Su-7IG [kód NATO: Fitter-B]

is an Experimental aircraft, the Sukhoi S-22I

Work on the development of experimental aircraft with variable geometry wings with the designation S-22I began in the design office P. About. Sukhoi in 1963 under the leadership of chief designer Nikolai G. Zirina. The development was launched on its own initiative, the ministry of aviation industry of the USSR was approved subsequently in the year 1965. Was chosen an effective solution when the fuselage of the aeroplane Su-7B was developed a new wing with variable geometry.

The wing was to consist of fixed sections, which were attached to the hull in the same fixing nodes as the wing of the aeroplane Su-7B and of moving the end parts of the wings. The fixed part of the wing at the same time contained spaces for the retractable main landing gear, retractable slotted flaps, the space for retraction of the movable parts of the wings and control units of the movable part and the premises for a fixed kanonovou armament. The fixed part has been discontinued weapons závěsníkem and on the upper part of the aerodynamic ridge.

The moving part of the wing consisted of the front leading edge, from the middle of the carrier, which contained an integral fuel tank and in the rear were hinged slotted flaps and ailerons. Later it was on the recommendation of the institute of CAGE the leading edge supplemented by a three-panel pull-out slots. The movable part of the wing was adjusted in the range of the angle of the arrow of the mean aerodynamic chord of 30° to 63°.

In the development of new wings, it was necessary to solve a number of new problems. The fixed and movable parts of the wings should be linked with massive main pivot junction and the rear movable auxiliary support. The biggest problem was with the development of the mechanism of rebuilding the wings. Initially it was assumed the use of the classic dvoupolohových hydraulic working cylinder. During the exam, but it turned out that the moving parts of the wing move heterogeneously, which would threaten the safety of the flight. Furthermore, it would be possible to use the intermediate position of the wing, for which calculations indicated large benefits for combat maneuvering and flight range of the aircraft. In the end it was chosen the use of hydraulic motors with reducer, a screw mechanism and the hydraulic brake, one set for each moving part. Moving parts, so it can be set at any angle to the arrow. The two movable parts of the wings were mechanically interconnected by a synchronization shaft, which synchronize their rebuilding and to allow the safe displacement of the wings during the withdrawal of one hydraulic motor. The configuration of the wings for take-off was fixed - wing angle of an arrow 30°, slats extended, flaps retracted for landing a wing of 30°, the slots, the inner and outer flaps extended. Rebuilding the wings should be propelled from the force of the hydraulic system of the aeroplane. The Pilot converted the wing of the control lever on the front dashboard, where it was located even the angle indicator arrow wings FARTED-2. The flap was controlled dvoupolohovými buttons (extended-retracted), the slots are ruled by a special switch on the dashboard.
The development wing was completed in 1965, by the end of 1965 was built the dragon of the aircraft S-22I-0 for static tests.

For the flight tests was chosen by the fuselage Su-7BM the serial number 4806 with engine AL-7F1. It was adjusted the middle part of the fuselage and from the aircraft was removed autopilot AP-28, the shock absorber D-2K and practically all the weaponry. Backup rychloměrná tube PVD-7 was placed on the right side of the bow of the aeroplane. Design work was completed in the summer of 1966 and 2. August 1966 the head of the pilot design of the office P.About. Sukhoi Vladimir Sergeyevich Ilyushin carried out with an experimental plane S-22I of the first years. Flight testing continued until November 1966, when they were on the airplane made some adjustments. The rear part of the fuselage was replaced with a new one, used on airplanes Su-7BKL, Su-7BMK and Su-7FOR with dvoukopulovým the brake parachute was modified displacement system of the input cone and protipumpážních door ESUV-1V so that protipumpážní the door could also serve as a přisávací, thus increased engine thrust during take-off. Were also made some adjustments to the hydraulic system of the airframe and the hull appeared and a new antenna for a radio station, and telecommunications system of recording flight data. Adjustments were completed in march 1967 and then continued flight tests at the airport in Achtjubinsku. It is interesting that so far not published any photos of the aircraft S-22I in the original form with the fuselage of the aeroplane Su-7BM.

The aircraft S-22I, also known as Su-7IG or MS-19, first introduced to the public at the air show at Domodedovo airport near Moscow on the 9th. June 1967. Tests with aircraft continued until 1972, inter alia, was to him, fitted a comprehensive system of automatic piloting SAU-22-1, have been tested different shapes of arches end of the wing and the aircraft serve for the training zalétávacích pilots in the development of the prototype S-32, later produced the serial Su-17. Experimental plane S-22I with the present day not preserved. In 1972 he was transferred to joukowski theorem the Military air academy in Moscow, where he was later taken away for scrap. At the department of aeronautical structures has been preserved only a small part of the wings.

Source:
Aviaciai astronautics yesterday, segodnya i zavtra no. 6,7/2011
Victor J. Markovskij, Igor In. Prichodčenko: Istrebitěl-bombardirovščik Su-17, ubijca "of",publishing Jauza, Eksmo 2013[/resources].

Prototyp sériovej verzie Su-17: S-22I.

http://www.airwar.ru/enc/fighter/su17.html

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