The RD-856 (Russian: Ракетный Двигатель-856, romanized: Raketnyy Dvigatel-856, lit. 'Rocket Engine 856', GRAU index: 8D69M), also known as the RD-69M, is a four-nozzle liquid-fuel rocket vernier engine, burning a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide (N2O4) oxidizer in a gas generator cycle.[3] It was used on the R-36, Tsyklon-2 and Tsyklon-3 second stage as thrust vector control by gimbaling of its nozzle.[3] The engine is distributed through a cylindrical structure that is integrated around the main engine RD-252 module. The structure includes aerodynamic protection for the nozzles.[2] The engine was started by a pyrotechnic ignitor.[2]
| Country of origin | Soviet Union |
|---|---|
| First flight | December 16, 1965 |
| Last flight | January 30, 2009 |
| Designer | Yuzhnoye Design Bureau |
| Manufacturer | Yuzhmash |
| Application | Vernier |
| Associated LV | R-36, Tsyklon-2 and Tsyklon-3 |
| Status | Out of production |
| Liquid-fuel engine | |
| Propellant | N2O4 / UDMH |
| Mixture ratio | 1.98 |
| Cycle | Gas generator |
| Configuration | |
| Chamber | 4 |
| Performance | |
| Thrust, vacuum | 54.23 kN (12,190 lbf) |
| Chamber pressure | 7.160 MPa (1,038.5 psi) |
| Specific impulse, vacuum | 280.5 s (2.751 km/s) |
| Burn time | Up to 163 s |
| Restarts | 1 |
| Gimbal range | ±30° |
| Dimensions | |
| Length | 0.9 m (2 ft 11 in) |
| Diameter | 3.35 m (11.0 ft) |
| Dry mass | 112.5 kg (248 lb) |
| Used in | |
| R-36, Tsyklon-2 and Tsyklon-3 second stage vernier | |
| References | |
| References | [1][2][3] |
The engine was serially produced between 1965 and 1992. It was first launched on December 16, 1965 on an R-36 and its last launch was on January 30, 2009 with the last launch of the Tsyklon-3. The production capability was restarted for the Tsyklon-4 but with the apparent cancellation of the program the engine would still be out of production.[4]
See also
editReferences
edit- ^ "RD-856". Encyclopedia Astronautica. Archived from the original on June 27, 2002. Retrieved 2016-07-06.
- ^ a b c Pillet, Nicolas. "Tsiklone - Le deuxième étage" [Tsyklon - The second stage] (in French). Kosmonavtika.com. Retrieved 2016-07-06.
- ^ a b c "RD-856". Yuzhnoye. Archived from the original on 29 May 2015.
- ^ Krebs, Gunter Dirk (2016-04-24). "Tsiklon". Gunter's Space Page. Retrieved 2016-07-05.
External links
edit- Yuzhnoye Design Bureau English-language home page Archived 2021-06-29 at the Wayback Machine
- Yuzhmash Home Page
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