RD-250
| 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 | [1][2][3][4][5][6] |
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.
Versions
The engine has seen different versions made:
- RD-250 (GRAU Index 8D518): Base engine of the family. Used on the R-36. A bundle of three RD-250 form the RD-251 cluser.
- RD-250P (GRAU Index 8D518P): Improved version of the RD-250. Used on the R-36P. A bundle of three RD-250P form the RD-251P cluser.
- RD-250M (GRAU Index 8D518M): Improved version of the RD-250P. Used on the R-36-O. A bundle of three RD-250M form the RD-251M cluser.
- RD-250PM (GRAU Index 8D518PM): Improved version of the RD-250M. Used on the Tsyklon-3. A bundle of three RD-250PM form the RD-261 cluser.
- RD-252 (GRAU Index 8D724): Vacuum optimized version of the RD-250. Used on the R-36 and Tsyklon-2 second stages.[4]
- RD-262 (GRAU Index 11D26): Improved version of the RD-252. Used on the Tsyklon-3 second stages.[7]
Modules
Some of these engines were bundled into modules of multiple engines. The relevant modules and auxiliary engines are:
- RD-251 (GRAU Index 8D723): A module comprising three RD-250. Propulsion module of the R-36 (8K67) first stage.[3]
- RD-251P (GRAU Index 8D723P): A module comprising three RD-250P. Propulsion module of the R-36P (8K68) first stage.
- RD-251M (GRAU Index 8D723M): A module comprising three RD-250M. Propulsion module of the R-36-O (8K69) and Tsyklon-2 first stage.
- RD-261 (GRAU Index 11D69): A module comprising three RD-250PM. Propulsion module of the Tsyklon-3 first stage.[8]
Comparison
| Engine | RD-250 | RD-250P | RD-250M | RD-250PM | RD-252 | RD-262 |
|---|---|---|---|---|---|---|
| GRAU | 8D518 | 8D518P | 8D518M | 8D518PM | 8D724 | 11D26 |
| Module | RD-251 | RD-251P | RD-251M | RD-262 | N/A | N/A |
| Module GRAU | 8D723 | 8D723P | 8D723M | 11D69 | N/A | N/A |
| Development | 1962-1966 | 1967-1968 | 1966-1968 | 1968-1970 | 1962-1966 | 1968-1970 |
| Propellant | N2O4/UDMH | |||||
| Combustion chamber pressure | 8.336 MPa (1,209.0 psi) | 8.924 MPa (1,294.3 psi) | ||||
| Thrust, vacuum | 881.6 kN (198,200 lbf) | 881.6 kN (198,200 lbf) | 881.6 kN (198,200 lbf) | 881.7 kN (198,200 lbf) | 940.8 kN (211,500 lbf) | 941.4 kilonewtons (211,600 lbf) |
| Thrust, sea level | 788.5 kN (177,300 lbf) | 788.5 kN (177,300 lbf) | 788.5 kN (177,300 lbf) | 788.7 kN (177,300 lbf) | N/A | N/A |
| Isp, vacuum | 301 s (2.95 km/s) | 301 s (2.95 km/s) | 301 s (2.95 km/s) | 301.4 s (2.956 km/s) | 317.6 s (3.115 km/s) | 318 s (3.12 km/s) |
| Isp, sea level | 270 s (2.6 km/s) | 270 s (2.6 km/s) | 270 s (2.6 km/s) | 269.6 s (2.644 km/s) | N/A | N/A |
| Length | 2,600 mm (100 in) | 2,600 mm (100 in) | 2,600 mm (100 in) | N/A | 2,190 mm (86 in) | 2,190 mm (86 in) |
| Diameter | 1,000 mm (39 in) | 1,000 mm (39 in) | 1,000 mm (39 in) | N/A | 2,590 mm (102 in) | 2,590 mm (102 in) |
| Dry weight | 728 kg (1,605 lb) | 728 kg (1,605 lb) | 728 kg (1,605 lb) | N/A | 715 kg (1,576 lb) | 715 kg (1,576 lb) |
| Use | R-36 (8K67) 1st stage | R-36P (8K67P) 1st stage | R-36-O (8K67-O) and Tsyklon-2 1st stage | Tsyklon-3 1st stage | R-36, R36P, R-36-O, Tsyklon-2 2nd stage | Tsyklon-3 2nd stage |
See also
- UR-36 - ICBM for which this engine was originally developed for.
- Tsyklon-2 - launch vehicle based on the UR-36.
- Tsyklon-3 - Three stage launch vehicle developed from the Tsyklon-2.
- Rocket engine using liquid fuel
References
- 1 2 "NPO Energomash list of engines". NPO Energomash. Retrieved 2015-06-20.
- ↑ "RD-250". Encyclopedia Astronautica. Retrieved 2015-06-20.
- 1 2 "RD-251". Encyclopedia Astronautica. Retrieved 2015-06-20.
- 1 2 "RD-252". Encyclopedia Astronautica. Retrieved 2015-06-20.
- ↑ Pillet, Nicolas. "Tsiklone - Le premier étage" [Tsyklon - The first stage] (in French). Kosmonavtika.com. Retrieved 2016-07-04.
- ↑ Pillet, Nicolas. "Tsiklone - Le deuxième étage" [Tsyklon - The second stage] (in French). Kosmonavtika.com. Retrieved 2016-07-04.
- ↑ "RD-262". Encyclopedia Astronautica. Retrieved 2015-06-20.
- ↑ "RD-261". Encyclopedia Astronautica. Retrieved 2015-06-20.
External links
- Yuzhmash official information on the RD-261.
- Encyclopedia Astronautica information on RD-250 base engine.
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