The RD861 engine is intended for thrust creation and flight control of Cyclone LV third stage along the active leg of trajectory in all
reference channels. The flight control is effected through the turbine gas distribution between the control nozzles under commands of the
control system.
Main advantages
- The engine provides double start and thrus level regulation.
- It has high power-mass characteristics owing to application of a chamber tube design.
Consumer's characteristics of RD-861 engine
The one-chamber engine of double start with pump-fed hypergolic propellants is designed under the generator scheme. The turbine's working
medium is a gas produced by the gas generator through combustion of main propellants. During the startup the TPU's rotor is spinned-up by
one pyrostarter from their cluster.The control units are governed by helium delivered into their pilot cavities from a pressure vessel
installed on the engine.
| Vacuum thrust, kgf | 8026 |
| Vacuum specific impulse, s | 317 |
| Mass, kg | 123 |
| Absolute pressure in CC, kgf/cm2 | 90,5 |
| Absolute pressure at nozzle exit, kgf/cm2 | 0,053 |
| Mixture ratio (MR) | 2,10 |
| Thrust regulation range, % | ±5 |
| Mixture ratio deviation from the nominal value, % | ±3,8 |
Propellants
- oxidizer
- fuel |
NTO
UDMH |
Min absolute inlet pressure during operation, kgf/cm2, at temperature of 35°Ñ, kgf/cm2
- oxidizer
- fuel |
4,55
2,5 |
Max steering forces generated by steering nozzles in channels, kgf:
- pitch and yaw
- roll |
160
12 |
| Burn time, s | 130 |
Development of the engine began in 1968 and was completed in 1972.
The engine was accepted for serial production. |
Development of company
