MiG-21 his / Yc-7 his / Tip 75

One of the lessons learned in combat over the Middle East and Viet­nam was that in order to defeat a turboprop-powered fighter one had

The MiG-21bis was developed especially for low – and medium-altitude combat. Here it is armed with two K-60M and two K-13M air-to-air missiles.

to involve it in close combat at low altitudes. To meet that challenge, the jet fighter had to be armed to the teeth and supplied with a good amount of fuel. It also needed to be a stable and maneuverable machine. The dominant feature of all of the MiG-21 variants reviewed thus far was their good performance at medium and high altitudes. But it had never performed up to par at low altitudes, because of some of the distinctive characteristics of such power plants as the R-11F2-300 and the R-13-300.

This is why it was decided in February 1971 to construct a new MiG-21 that would be especially efficient at low altitudes and high indi­cated airspeeds. The new ОКБ offspring was named the MiG-21 bis. It was powered by a new engine, the R-25-300. It was rated at 4,020 daN (4,100 kg st) dry—roughly equivalent to the R-13-300—but had a much higher afterburning ratio in that its reheated thrust was rated at 6,960 daN (7,100 kg st). Moreover, at Mach 1 and beyond it could utilize a special afterburning regime called ChR (Chrezuichayniy Rezhim: excep­tional rating) that permitted it to obtain a peak thrust of 9,700 daN (9,900 kg st) for as long as three minutes between 0 and 4,000 m (0 and 13,120 feet).

The MiG-21 bis could also be fitted with two SPRD-99 solid rocket boosters rated at 2,450 daN (2,500 kg st) apiece. Their kinetic energy topped 46,000 kgm/sec (451,000 W) for between 10 and 17.8 seconds according to temperature. The total capacity of the fuel tanks was 2,880

1 (760 US gallons). Installation of the new engine forced engineers to modify the fuel system with a booster pump for the afterburner. The aircraft was fitted with the new RSBN-2S short-range navigation sys­tem, similar to the Shoran and replaced in late-series machines by the RSBN-5S; it also received new instrument approach equipment Together, those new systems enabled the pilot to navigate accurately in even the worst weather. Automatic monitors for the airframe and engine significantly reduced maintenance downtime.

In addition to its built-in GSh-23 cannon, the MiG-21 bis was armed for close combat with R-55 and R-60M (K-60M) air-to-air missiles and with the R-13M (K-13M), which had twice the range of the R-3S and

The R-25-300, rated at 6,160 daN (7,100 kg st) with afterburner, gave the MiG-21bis excellent takeoff and climb performance.

could be fired under a much higher load factor. The airborne radar was the RP-22 Sapfir-21. The MiG-21 bis was accepted into WS fighter air regiments in February 1972 and was mass-produced in the Gorki facto­ry. India was granted the manufacturing license in 1974.

Specifications

Span, 7.154 m (23 ft 5.7 in); fuselage length (except cone), 12.285 m (40 ft 3.7 in); overall length (except probe), 14.7 m (48 ft 2.3 in); wheel track, 2.787 m (9 ft 1.7 in); wheel base, 4.7] m (15 ft 5.4 in); wing area, 23 m2 (247.6 sq ft); takeoff weight with two R-3S missiles, 8,725 kg (19,230 lb); max takeoff weight, 9,800 kg (21,600 lb); max takeoff weight on rough strip or metal-plank strip, 8,800 kg (19,395 lb); max takeoff weight with KT-92D wheels and 42A or 058 (800 x 200) tires, 10,400 kg (22,920 lb); fuel, 2,390 kg (5,270 lb); wing loading, 379.3- 426.1-382.6-452.2 kg/m2 (77.8-87.4-78.4-92.7 lb/sq ft); max operating limit load factor, 8.5.

Performance

Max speed, 2,175 km/h at 13,000 m (1,175 kt at 42,640 ft); max Mach number, 2.05; max speed at sea level, 1,300 km/h (702 kt); climb rate at sea level (half internal fuel, full thrust) with two R-3S missiles, 230 m/sec (45,275 ft/min); climb to 17,000 m (55,760 ft) in 8.5 min; ser­vice ceiling, 17,500 m (57,400 ft); landing speed, 250 km/h (135 kt);

Fou Typical Mission Profiles for the MiG-21 bis Types of missions Fuel Weapons Radius of action Time No 1 bombing 800-1 (211-US gal) two 500-kg 290 km 1 mm mission* drop tank (1,100-lb) bombs (170 mi) over target No. 2 bombing 800-1 (211-US gal) two 250-kg 330 km 1 min mission3 drop tank (550-lb) bombs (205 mi) over target No. 1 interception mission13 no drop tank two R-3S and two R-60 missiles 330 km (205 mi) 2 mm m intercept area No. 2 interception 800-1 (211-US gal) two R-3S and 450 km 2 min missionb drop tank two R-60 missiles (280 mi) in intercept area Notes These lo-lo-lo missions are floum at an average altitude of200 m (650 ft) outbound and inbound These missions are flown at high altitude first 8 000 m (26 250 ft) then 5 000 m (16 400 ft) and 10,000 m (32 800 ft) outbound, 10 000 m (32 800 ft) for the return flight

range in clean configuration, 1,225 km at 11,000 m (760 mi at 36,080 ft), 1,110 km at 14,000 m (690 mi at 45,920 ft); with 800-1 (211-US gal) drop tank, 1,430 km at 14,000 m (890 mi at 45 920 ft), with two R-3S missiles and 490-1 (129-US gal) drop tank, 1,355 km at 11,000 m (840 mi at 36,080 ft); with two R-3S missiles and 800-1 (211-US gal) drop tank, 1,470 km at 10,000 m (910 mi at 32,800 ft), takeoff roll, 830 m (2 720 ft), landing roll with SPS and tail chute, 550 m (1 800 ft)