"The T-4 supersonic reconnaissance and attack weapons system (production code "100") was intended to search for and destroy large surface targets such as aircraft carriers and missile carrying ships as well as for reconnaissance. This concept arose in the early sixties. Primary design emphasis was on the development of an airframe capable of long range flight at three times the speed of sound.

In addition to its main mission, the preliminary design described the T-4 as:

- a reconnaissance aircraft;

- a long-range interceptor weapons system;

- a supersonic passenger aircraft.

It was planned that the aircraft, with a takeoff weight of 220,000-243,000 lb (100,000-110,000 kg), would be capable of a 3,728 mi (6,000 km) range, at 66,000-79,000 ft (20,000-24,000 m) altitude, without external tanks, at a speed 1,864-1,988 mph (3,000-3,200 km/h). In April 1963, the preliminary design was completed and was presented to the VVS and the State Aircraft Technique Committee.

By order of the Deputy Commanderin-Chief of the VVS, a special commission was created and it studied the project from May 23 until June 3 of 1963. This commission concluded that the T-4 long range supersonic aircraft, suggested by the Sukhoi Design Bureau, satisfied the VVS requirements and would outperform other aircraft of its type in flight performance, armament and avionics capabilities. The commission further commented that the results of the research work on the attackreconnaissance aircraft, powered by two R-15BF-300 or RD17-15 turbojets, corresponded to the specified requirements of the standard Soviet preliminary design phase and could be considered as a base for building a mockup and for further fullscale development work. By the end of 1963, based on the positive conclusion of the commission, the T-4 project received a further go ahead in the form of a Communist Party Central Committee and Council of Ministers resolution. Flight testing was to begin in 1968.

Many Soviet aerospace scientific organizations of the State Aircraft Technique Committee were involved in the design work along with the Sukhoi Design Bureau. The main plan was developed and design work was coordinated by the end of 1963 and the preliminary design was completed in 1964.

T-4 DESCRIPTION (PRELIMINARY

DESIGN)

It was proposed that the aircraft be of canard configuration featuring movable forward control surfaces.

Fuselage: The fuselage, of high fineness ratio, had a protruding canopy that was integrated with an upper fairing. This upper fairing joined with the vertical stabilizer root section. Main aircraft systems and equipment, including the integral fuel tanks, were mounted in the fuselage.

Wing: The aircraft was to have a thin swept delta wing with ailerons and elevons. Paired engine nacelles, with air intakes, were to be installed under the wing.

Empennage: The canard surfaces were equipped with elevators. They were mounted on the forward fuselage. Mounted on the rear fuselage was the vertical stabilizer.

Landing gear: It was proposed to equip the aircraft with a tricycle landing gear. Main gear struts, equipped with twin tandem trucks, retracted in wells between the engine air ducts. The nose gear strut, with wheels, retracted inwards into the fuselage.

Powerplant: The powerplant consisted of four R-15BF-300 or RD-17-15 turbojets, rated at 33,070 lb (15,000 kg) afterburning thrust each. The engines were installed in pairs in two, separate engine nacelles under the wing. Air intakes for each engine nacelle were separated by walls and were equipped with vertical ramps. Air intake leading edges extended forward of the wing leading edge. The aircraft fuel system was mounted in the fuselage.

Armament: The aircraft weapons (air-to-surface missiles) were to be installed on three hard points between the engine nacelles. One hard point coincided with the aircraft centerline.