RD-251
| Country of origin | USSR |
|---|---|
| First flight | December 16th, 1965 |
| Designer | OKB-456 |
| Manufacturer | PA Yuzhmash |
| Associated L/V | R-36, Tsyklon-2 and Tsyklon-3 |
| Status | Out of Production |
| Liquid-fuel engine | |
| Propellant | N2O4 / UDMH |
| Mixture ratio | 2.6 |
| Cycle | Oxidizer Rich Staged Combustion |
| Configuration | |
| Chamber | 2 |
| Performance | |
| Thrust (vac.) | 788 kN (177,000 lbf) |
| Thrust (SL) | 882 kN (198,000 lbf) |
| Chamber pressure | 8.33 MPa (1,208 psi) |
| Isp (vac.) | 301 s (2.95 km/s) |
| Isp (SL) | 270 s (2.6 km/s) |
| Dimensions | |
| Dry weight | 788 kg (1,737 lb) |
| Used in | |
| R-36, Tsyklon-2 and Tsyklon-3 first stage | |
| References | |
| References | |
The RD-250 (GRAU Index 8D518) is the base version of a dual nozzle family of liquid rocket engines, burning N2O4 and UDMH in the oxidizer rich staged combustion cycle. The RD-250 was developed by OKB-456 for Yangel's PA Yuzhmash ICBM, the R-36 (missile) (8K67). Its variations were also used on the Tsyklon-2 and Tsyklon-3 launch vehicles. It was supposed to be used on the Tsyklon-4, but since the cancellation of the project it should be considered as out of production.
The engine has seen different versions made:
Some of these engines were bundled into modules of multiple engines. The relevant modules and auxiliary engines are:
...
Wikipedia