175

The 1-75 supersonic interceptor was a direct descendant of the I-7U equipped with the more sophisticated Uragan-5 interception system. The operation of the Uragan-5B modified radar was identical to that of the Izumrud or Almaz except for one thing: it had only one transmit­ter, one antenna, one display system, and two operating modes: search and target designation. The Uragan-5 system also comprised the AP-39 Uragan-5V autopilot, the Uragan-5D airborne computer, and the Ura – gan-5T-l radar control unit, plus two K-8 air-to-air missiles that weighed 275 kg (605 pounds) apiece.

This aircraft was engineered to intercept automatically high-alti- tude supersonic bombers day or night or in bad weather and to destroy them as far away as possible from their intended targets. With two drop tanks its tactical radius of action was 720 km (447 miles). It could attack enemy aircraft at speeds between 800 and 1,500 km/h (432 and 810 kt) and altitudes between 10,000 and 20,000 m (32,800 and 65,600 feet). Its radar detection range was 30 km (18.6 miles), and it could lock onto targets 20 km (12.4 miles) away.

The 1-75 differed from the 1-7U in its forward fuselage, where the Uragan-5 accessory unit was housed. Moreover, in place of cannons it

258

The 1-75 was in fact an I-7U minus the cannons equipped with the new Uragan-5B radar, and armed with two K-8 air-to-air missiles

The I-75’s nose cone is much bulkier than that of the I-7U due to the larger radar antenna.

had wing pods for air-to-air missiles. To increase its efficiency, the fin height was increased and the sweep angle at the leading edge was reduced by 2.5 degrees. The cockpit was equipped with the only type of ejection seat available at MiG at the time. Tail chute canisters were located on either side of the ventral fin. The engine air intake cone was fixed. The air intake duct flow rate was controlled by a translating outer ring on the cylindrical end of the nose cone.

The I-75’s flying controls were of the rigid type (tubular actuating rods in duralumin). The pitch channel was fitted with two BU-44B irre­versible servo-controls and the ARU-3V artificial feel system. The BU – 44 aileron servo-control and the BU-45 rudder servo-control were irre­versible as well. Like the I-7U, the 1-75 was powered by a Lyulka AL-7F turbojet that provided dry thrust of 6,155 daN (6,240 kg st) or 9,035 daN (9,220 kg st) with afterburner. The aircraft was moved to the test center on 1 March 1958 but did not fly until problems in the cockpit ejection system were ironed out.

Watched closely by A. N. Soshm, the chief engineer, G. K. Mosolov made the first flight on 28 April 1958 and four others thereafter. Between 15 May and 24 December the radar was installed and efforts were made to improve the engine and the Uragan-5 system. Flight tests resumed on 25 December and were terminated on 11 May after eigh­teen flights with the radar operating.

Specifications

Span, 9.976 m (32 ft 8.7 in); overall length, 18.275 m (59 ft 11.5 in); fuselage length (except cone), 15.6 m (51 ft 2.2 in); wheel track, 3.242 m (10 ft 7.6 in); wheel base, 5 965 m (19 ft 6.9 in); wing area, 31.9 m2 (343.4 sq ft); empty weight, 8,274 kg (18,235 lb); takeoff weight, 10,950 kg (24,135 lb); max takeoff weight, 11,470 kg (25,280 lb); fuel, 2,000 kg (4,410 lb); oil, 17 kg (37 lb); wing loading, 343.3-359.6 kg/m2 (70.4-73.7 lb/sq ft); max operating limit load factor, 9.

Performance

Max speed, 2,050 km/h at 11,400 m (1,107 kt at 37,400 ft); 1,870 km/h at 12,900 m (1,010 kt at 42,300 ft); 1,670 km/h at 12,400 m (902 kt at 40,670 ft) with two K-8 missiles; design climb to 6,000 m (19,680 ft) in 0.93 min; to 11,000 m (36,080 ft) in 3.05 min; service ceiling, 21,000 m (68,900 ft); landing speed, 240 km/h (130 kt); endurance with after­burner between 10,000 m and 15,000 m (32,800 and 49,200 ft), 25 min; range at 10,000 m (32,800 ft), 1,200 km (745 mi); at 12,000 m (39,360 ft), 1,470 km (910 mi); takeoff roll, 1,500 m (4,920 ft); landing roll,

2,0 m (6,560 ft).

The Ye-150 served as the test bed for the Mikulin-Tumanskiy R-15-300, which would later power the MiG-25