Liquid
rocket engine
RD-261

Cyclone-4 LV first stage sustainer engine provides second stage starting up to the first space speed in the upper air layers. 

The RD-261 consists of 3 double-chambers blocks which are assembled on a single frame fixing to a completed unit. Each block has its own turbo pump set and produced on the scheme without afterburning of turbine operating body. Combustion products of main propellant components are used as a turbine operating body.

Technical characteristics

Value

Propellant components

NTO (N2O4) + UDMH ((CH3)2N2H2)

Combustor pressure, kgs/sq.cm

88,8

Specific propulsive burn at the sea level, s 

268,5

Sea level thrust, s

251082

Vacuum specific propulsive burn, s

299,0

Vacuum thrust, s

279603 

Propellant mixture ratio

2,65

Firing time, s120