Country of origin China[1]
First flight 2015-09-20
Designer Academy of Aerospace Liquid Propulsion Technology[1]
Associated L/V Long March 6 and Long March 7[2][3]
Predecessor RD-120[1]
Status In service
Liquid-fuel engine
Propellant LOX[4] / RP-1[4]
Mixture ratio 2.5[4]
Cycle Oxidizer-rich Staged combustion[4]
Chamber 1[4]
Thrust (vac.) 176.5 kN (39,700 lbf)[4]
Thrust (SL) 147.1 kN (33,100 lbf)[4]
Chamber pressure 12 MPa (1,700 psi)[4]
Isp (vac.) 342 seconds (3.35 km/s)[4]
Length 2,325 millimetres (91.5 in)[4]
Diameter 946 millimetres (37.2 in)[4]
Used in
Long March 6 second stage and Long March 7 second stage.[2][3][4]

The YF-115 is a Chinese liquid rocket engine burning LOX and kerosene in an oxidizer-rich staged combustion cycle.[4] A high efficiency/high thrust environmental friendly rocket engine was always an objective within Programme 863. But the Chinese industry was not mature enough to produce such a rocket until they obtained examples (and probably documentation) of the Russian RD-120 in the early 1990.[5] Development began in the 2000s, along with its sibling, the bigger YF-100, which would power the LM-5, LM-6 and LM-7 boosters and first stages.[5][6][7] Testing was directed by the China National Space Administration (CNSA) commencing in 2005. Development works are mainly carried out by the Xi'an Aerospace Propulsion Institute. It will be used as upper stage engine for China's next generation of medium and light environmental-friendly launch vehicles, namely the Long March 6 and the Long March 7.[5][6][7] During early 2012, the engine system successfully passed vacuum testing.[8] It is China's first upper stage rocket engine to adopt the staged-combustion cycle.

In the LM-6 upper stage it will use a single YF-115 with gimbaled mount. While the LM-7 upper stage will use four such engines. But in this latter case, two engines will be fixed and two will be gimbaled.[4]


  1. ^ a b c "YF-100" (in Chinese). Retrieved 2015-07-02. 
  2. ^ a b Gunter Dirk Krebs. "CZ-6 (Chang Zheng-5)". Gunter's Space Page. Retrieved 2015-07-02. 
  3. ^ a b Gunter Dirk Krebs. "CZ-7 (Chang Zheng-5)". Gunter's Space Page. Retrieved 2015-07-02. 
  4. ^ a b c d e f g h i j k l m n "长征七号运载火箭 (The Long March 7 Launch Vehicle)" (in Chinese). baike.com. Retrieved 2015-07-03. 
  5. ^ a b c "Chang Zheng-5 (Long March-5)". SinoDefence. Retrieved 2015-07-02. 
  6. ^ a b "Chang Zheng-6 (Long March-6)". SinoDefence. Retrieved 2015-07-02. 
  7. ^ a b "Chang Zheng-7 (Long March-7)". SinoDefence. Retrieved 2015-07-02. 
  8. ^ "长征七号火箭发动机抽真空系统顺利通过试验 (Long March 7 rocket engine system passes vacuum test)" (in Chinese).