RD-8

RD-8 (РД-8)
Country of originSoviet Union
First flightApril 13, 1985
DesignerYuzhnoye Design Bureau
ManufacturerYuzhmash
ApplicationSecond Stage Vernier
Associated LVZenit
SuccessorRD-809M
StatusIn Production
Liquid-fuel engine
PropellantLOX / RG-1
Mixture ratio2.4
CycleStaged Combustion
Configuration
Chamber4
Performance
Thrust, vacuum78.45 kN (17,640 lbf)
Chamber pressure7.747 MPa (1,123.6 psi)
Specific impulse, vacuum342 s (3.35 km/s)
Burn time1100 s
Gimbal range±33°
Dimensions
Length1,500 mm (59 in)
Diameter4,000 mm (160 in)
Dry mass380 kg (840 lb)
Used in
Zenit family second stage
References
References

The RD-8 (Russian: РД-8 and GRAU Index: 11D513) is a Soviet / Ukrainian liquid propellant rocket engine burning LOX and RG-1 (a rocket grade kerosene) in an oxidizer rich staged combustion cycle. It has four combustion chambers that provide thrust vector control by gimbaling each of the nozzles in a single axis ±33°. It was designed in Dnipropetrovsk by the Yuzhnoye Design Bureau as the vernier thruster of the Zenit (GRAU: 11K77) second stage. As such, it has always been paired with the RD-120 engine for main propulsion.

It can only be started once, and as a high altitude engine it has a thrust of 78.45 kN (17,640 lbf) and a specific impulse of 342 s (3.35 km/s). It is the first ever steering engine to use the staged combustion cycle, and as such is the basis for a family of planned engines for the Mayak launch vehicle family.

The engine itself is built like a hollow cylinder, with a cylindrical space in the center so the RD-120 nozzle can pass through.

Derivatives

Whilst Yuzhnoye's propulsion experience had been mostly on hypergolic propellants engines, like RD-855 or RD-861, they are considered too toxic for current ecological standards. While Yuzhnoye still offer to develop hypergolic propulsion, such as RD-843 for the Vega's AVUM stage or the Tsyklon-4 project, Yuzhnoye selected a more environmentally friendly LOX and kerosene propellant for the Mayak launch vehicle family.

Not only had Yuzhnoye mastered the most complex cycle for the propellant (oxidizer rich staged combustion cycle) with the RD-8, but they had worked closely with NPO Energomash during the RD-120 program. The manufacturing is done at its sister company of Yuzhmash in Dnipropetrovsk, and the RD-120 thrust augmentation project of 2001 to 2003 had been a mixed project between the three companies.

On the base of this experience, a family of derivatives engines were proposed. While the RD-801 and RD-810 are really just based on the general technology, the other members of the family are related enough that they reuse many components of the RD-8. One characteristic of this family is the limitation of keeping the preburner output temperature below 500 °C (932 °F).

See also

References

  1. 1 2 Gunter Dirk Krebs (2015-12-15). "Zenit family". Gunter's Space Page. Retrieved 2016-07-14.
  2. 1 2 Brügge, Norbert (2016-07-11). "Ukrainian space-rocket and missile liquid-propellant engines". b14643.eu. Retrieved 2016-07-14.[dead link]
  3. 1 2 3 4 5 6 7 8 9 10 Degtyarev, A . V.; Shulga, V . A.; Zhivotov, A . I.; Dibrivny, A . V. (2013). "Создание семейства кислородно-керосиновых жидкостных ракетных двигателей на базе отработанных технологий для перспективных ракет-носителей гп "Кб «Южное"" [The development of LOX - kerosene liquid rocket engines family for perspective launch vehicles of SDO Yuzhnoye based on proven technologies] (PDF). Авиационно - космическая техника и технология (in Russian). 2013 nr. 01 (98). National Aerospace university them. NE Zhukovsky: 44–50. ISSN 1727-7337. Archived from the original (PDF) on 2016-08-16. Retrieved 2016-07-14.
  4. ↑ "RD-8". Defense Industry Of Ukraine Products And Services. Archived from the original on 2016-08-18. Retrieved 2016-07-14.
  5. 1 2 3 "RD-8". Yuzhnoye. Archived from the original on 2016-07-09. Retrieved 2016-07-14.
  6. 1 2 3 "Liquid rocket engine RD-8". Yuzhmash. Retrieved 2016-07-14.
  7. 1 2 "Двигатели 1944-2000: Аавиационные, Ракетные, Морские, Промышленные" [Aviadvigatel 19442-2000: Aviation, rocketry, naval and industry] (PDF) (in Russian). pp. 265–266. Retrieved 2015-07-25.
  8. 1 2 Hendrickx, Bart; Vis, Bert (2007-10-04). Energiya-Buran: The Soviet Space Shuttle (UK 2007 ed.). Springer. p. 80. ISBN 978-0-387-69848-9.
  9. ↑ Zak, Anatoly (2013-01-31). "Stage II of the Zenit rocket". Russian Space Web. Retrieved 2016-07-14.
  10. ↑ "RD-802". Defense Industry Of Ukraine Products And Services. Archived from the original on 2016-08-18. Retrieved 2016-07-14.
  11. ↑ "RD-809". Yuzhnoye. Archived from the original on 2016-07-09. Retrieved 2016-07-14.
  12. 1 2 "RD-809K". Yuzhnoye. Archived from the original on 2016-07-09. Retrieved 2016-07-14.
  13. ↑ "Liquid rocket engine RD-809K – Production Association Yuzhny Mashinbuilding Plant". Archived from the original on 2021-12-10. Retrieved 2025-08-24.