YF-1

YF-1B

Country of origin	China
Date	1958-1969
Designer	Academy of Aerospace Liquid Propulsion Technology, Ren Xinmin, Mo Tso-hsin, Zhang Guitian
Associated LV	DF-3A, DF-4 and Long March 1
Predecessor	С2.1100
Successor	YF-20
Status	Retired
Liquid-fuel engine
Propellant	N2O4 / UDMH
Cycle	Gas Generator
Configuration
Chamber	1
Nozzle ratio	10
Performance
Thrust, vacuum	303.6 kN (68,300 lbf)
Thrust, sea-level	275.3 kN (61,900 lbf)
Chamber pressure	7.1 MPa (1,030 psi)
Specific impulse, vacuum	267.4 seconds (2.622 km/s)
Specific impulse, sea-level	242.5 seconds (2.378 km/s)
Burn time	140s
Dimensions
Diameter	56 centimetres (22 in)
Used in
DF-3A, DF-4 and Long March 1 first stage.
References
References	[1][2][3][4][5][6] [7][8]

The YF-1 was a Chinese liquid rocket engine burning N₂O₄ and UDMH in a gas generator cycle. It is a basic engine which when mounted in a four engine module forms the YF-2. It was used as the basis for developing a high altitude version known as the YF-3.^[2][9]

Some authors state that it was a direct copy of С.2.1100/С.2.1150 La-350 booster engine developed by Isayev OKB-2 (NII-88).^[10] What is known is that the engine development had great trouble with combustion instabilities and it took a long time to have a reliable combustion.

Versions

The basic engine has been used since the DF-3 rocket and has been the main propulsion of the Long March 1 orbital launch vehicles.^[2]

• YF-1: Core engine. Flown originally on the DF-3. Used UDMH/AK27S as propellant. Allegedly a copy of OKB-2's С.2.1150.^[3][10]
• YF-1A: Core engine. Improved version that would power the DF-3A, DF-4 and Long March 1.^{[3][2][10][11]}
• YF-1B: Core engine. Improved version used on the Long March 1D. Switched propellants to UDMH/N₂O₄^[2]
• YF-3: Upper stage version. Used on the DF-4.^[2]
• YF-3A: Improved upper stage version. Used on the Long March 1.^[2]

Modules

While the basic engine was used multiple times, it was only used as a single engine for booster application. It is usually bundled into modules of multiple engines.

The relevant modules for first stage application are:

• YF-2: A module comprising four YF-1. Flown originally on the DF-3.^[3]
• YF-2A: A module comprising four YF-1A. Improved version. Used on the DF-3A, DF-4 and Long March 1.^[3][2]
• YF-2B: A module comprising four YF-1B. Improved version. Final version used on the Long March 1D.^[2]

See also

• DF-3A
• DF-4
• Long March 1 (rocket family)
• Long March 1
• Long March 1D

References

1. Norbert Bgügge. "Asian space-rocket liquid-propellant engines". B14643.DE. Archived from the original on 2015-07-17. Retrieved 2015-07-25.
2. Norbert Bgügge. "Propulsion CZ-1". B14643.DE. Retrieved 2015-07-25.
3. Norbert Bgügge. "The Chinese DF-3 missile". B14643.DE. Archived from the original on 2015-10-17. Retrieved 2015-07-25.
4. "Long March". Rocket and Space Technology. Retrieved 2015-07-25.
5. "CZ-1". Encyclopedia Astronautica. Archived from the original on May 1, 2002. Retrieved 2015-07-25.
6. "YF-2A". Encyclopedia Astronautica. Archived from the original on 2015-08-24. Retrieved 2015-07-25.
7. "YF-3". Encyclopedia Astronautica. Archived from the original on 2015-08-24. Retrieved 2015-07-25.
8. Harvey, Brian (2004). "Launch Centers Rockets and Engines". China's Space Program — From Conception to Manned Spaceflight. Springer Science & Business Media. p. 230. ISBN 978-1852335663. Retrieved 2015-07-15.
9. Mowthorpe, Matthew (2004). "Chinas Military Space Program". The Militarization and Weaponization of Space. Lexington Books. p. 90. ISBN 978-0739107133. Retrieved 2015-07-15.
10. "Dong Feng-3 (CSS-2)". SinoDefence. Archived from the original on 2015-11-23. Retrieved 2015-07-25.
11. "Dong Feng-4 (CSS-3)". SinoDefence. Archived from the original on 2015-11-23. Retrieved 2015-07-25.