česky english

R-79

AMNTK Soyuz, Russia

R-79V-300 is the first-ever engine with thrust vectoring and afterburner at the same time. This allowed the engine equipped plane to take off and land vertically and also to fly supersonically. Engine developement started probably in 1977 under the lead of V. A. Kobchyenko. The developement process did not run as planned and the first flight of new fighter plane had to be postponed a few years. The engine was ready for ground testing by the and of 1984. Yak-41M (redesignated to Yak-141 later) took off on 9th March 1987 for the first time. The fighter project has been cancelled in 1991 but engine developement continued. Twelve engines accomplished 3500 hours of ground testing in 1993. Another source states that there were 26 engines built till autumn 1992, 16 of them were ready to be tester in the air. Not all were actually installed on the fighter.

Engine has reportedly 1-stage low pressure compressor (fan) and 6-stage high pressure compressor with ability to withstand air flow distortion in inlet. A part of air from high pressure compressor is bypassed and lead to a few control nozzles on plane's airframe. Totally new is the exhaust nozzle which comprises of two rotating sections. Their mutual rotation allows the exhaust flow to be divertes 62 or 95 degrees down with no restriction to power setting of the engine. You can see the function of such nozzle on this videoclip od american F-35 plane. The nozzle is usable only for takeoff and landing, is not intended to improve maneuverability. It's service life is at least 1500 cycled Její životnost je nejméně 1500 turn cycles. Control system of engine is electronical with hydromechanical backup.

Further developement lead to advanced version R-79M with the thrust of 176.5 kN, with FADEC, new combustion chamber and 2D vectoring axisymmetrical (?) nozzle with deflection up to ± 20 degrees. The engine was considered in the first phase of S.22 plane preliminar design which lead to experimental plane S-37.

Another engine based on R-79V-300 is the R-179-300, thrust class 200 kN, developed in mid 90s. Engine characteristics class it to generation 4+, self control system pushes it near the 5th generation. Expected application was on varions types of military planes - from light combat planes to high performance fighter planes, probably mainly made by Sukhoi design bureau. R-179-300 with flat vectorized nozzle is a rival to Lyulka's (Saturn's) AL-41F.

Finally the VK-21 is an unaugmented modification of R-179-300 it thrust class of 120 kN. Kilometrical fuel comsumption is said to be almost the same while flying subsonicaly and supersoncaly, so the engine's optimal for the new (second) generation of supersonic passenger planes with weight of 40 to 110 tons. VK-21 has been developed around 1999.

R134-300 if a turbofan engine without afterburner for passenger planes with supercruise at speed of M=2,0. The engine seems to be parametrically very close to VK-21, it's the same type maybe.

BASIC CHARACTERISTICS OF R-79V-300, R-179-300 and VK-21

Type - R-79V-300 R-179-300 VK-21 R-134-300 *
Thrust - maximal (H=0, M=0) kp     11300 11000
- afterburner (H=0, M=0) kp 15680 20400    
- cruise (H=11km, M=0,9) kp     2000  
Thrust - maximal thrust (H=0, M=0) kg.kp-1.h-1 0,647 0,628    
- afterburner (H=0, M=0) kg.kp-1.h-1 1.66* 1,85    
- cruise (H=16km, M=2) kg.kp-1.h-1     1,14 1,14
- cruise (H=11km, M=0,9) kg.kp-1.h-1     0,835  
Airflow kg.s-1 180 180 180 179
Overall pressure ratio - 22 25 22,4 22,4
Bypass ratio - 0,81 0,73 0,81 0,81
Turbine inlet temperature °C 1357*   1327 1327
Maximal diameter mm 1720
1370*
1750 1250 1250
Lenght mm 5230
4780*
5610 4640 5320
Weight kg 2750 2880 2350  
Dry weight kg 1850*     1900