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Rocket engine From Wikipedia, the free encyclopedia
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 gas-generator open cycle.[7] The RD-250 was developed by OKB-456 for Yangel's PA Yuzhmash ICBM, the R-36 (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.
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Country of origin | USSR |
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First flight | December 16th, 1965 |
Designer | OKB-456 |
Manufacturer | PA Yuzhmash |
Associated LV | R-36, Tsyklon-2 and Tsyklon-3 |
Status | Out of Production |
Liquid-fuel engine | |
Propellant | N2O4 / UDMH |
Mixture ratio | 2.6 |
Cycle | Gas-generator |
Configuration | |
Chamber | 2 |
Performance | |
Thrust, vacuum | 882 kN (198,000 lbf) |
Thrust, sea-level | 788 kN (177,000 lbf) |
Chamber pressure | 8.33 MPa (1,208 psi) |
Specific impulse, vacuum | 301 s (2.95 km/s) |
Specific impulse, sea-level | 270 s (2.6 km/s) |
Dimensions | |
Dry mass | 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 engine has seen different versions made:
Some of these engines were bundled into modules of multiple engines. The relevant modules and auxiliary engines are:
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-261 | 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 kN (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 |
Several experts think that technology from the RD-250 engine could have been transferred to North Korea from Ukraine. This transfer would explain the rapid progress of North Korea in the development of two new missiles: the intermediate-range Hwasong-12 and the intercontinental ballistic missile (ICBM), Hwasong-14. Due to complexity of the technology involved in this type of engine, modifications or reverse engineering seem difficult to achieve. Thus it is believable that complete hardware could have been bought on black market and directly shipped to North Korea, by Russia or Ukraine.[10] Conversely, there is analysis[11] (made by two Ukrainian authors) suggesting an alternative mechanism for North Korea to receive R-36 missile engines, or an entire missile, from USSR or Russia.