YF-40

The YF-40 is a Chinese liquid rocket engine burning N₂O₄ and UDMH in a gas generator cycle. It has dual gimbaling combustion chambers.

YF-40B

Country of origin	China
First flight	1995-06-01
Designer	Academy of Aerospace Liquid Propulsion Technology
Associated LV	Long March 1D, Long March 4
Status	In Production
Liquid-fuel engine
Propellant	N2O4 / UDMH
Mixture ratio	2.14
Cycle	Gas Generator
Configuration
Chamber	2
Nozzle ratio	55
Performance
Thrust, vacuum	103 kN (23,000 lbf)
Chamber pressure	4.6 MPa (670 psi)
Specific impulse, vacuum	303 seconds (2.97 km/s)
Burn time	412s
Gimbal range	±4.5°
Dimensions
Length	120 centimetres (47 in)
Diameter	63 centimetres (25 in)
Dry mass	83 kg (183 lb)
Used in
Long March 1D second stage and Long March 4 third stage.
References
References	[1][2][3][4][5][6]

Originally it was developed for the Long March 1D second stage.^[6] It is used on the third stage of the Long March 4 family of launch vehicles.^[1][3][7]