This is a Chinese rocket engine manufacturer, which is important for its range of engines and the ability to make space flights, to position satellites, and missiles

-One of the first engines of this company was the one shown below.

In general, all engines use liquid fuel, using turbopumps like the very bulky one we see and with exhaust nozzle. This is possibly Vernier type thruster to intervene in the rocket direction.

"Two of the first engines"

-The YF-20A model, which delivers 76,500 Kgf. of thrust with N2O4/UDM propellants, is a cluster of various engines, generally four.

“YF-20A” (PiP)

-The YF-20B was used from 1975 to 1999 having made 172 shots. With 83,250 Kgf thrust for about 170 sec.

-The YF-22 that delivers 73,200 Kgf is a group or cluster when it is coupled to four YF-23s, with 1124 Kgf. each. They were used between 1972 and 1982.

-The YF-25 has one chamber and produces 80,300 Kgf of thrust. Sometimes it appears as FY-25.

"Group of 4 YF engines"

-The YF-2A used nitric acid and UDMH, giving 31200 Kgf. It was used in rockets of the CZ-1 series between 1970 and 1995. It consisted of a 4-engine cluster of YF-1s

-The YF-3 delivered 30000 Kgf. and made a flight in 1995. The YF-40 only gives 5,000 Kgf (1988-1999).

-Another cluster, the YF-73, has four small engines of only 1,125 Kgf. using LOX/LH2.

“Beijing YF-73” (PiP)

From appendix 9: We are getting to know more engines that are built in that country and are used in space and defense programs like this relationship with CALT for the famous "Long March" rockets.

-CALT is the "China Academy of Launch-Vehicle Technology" who designs the material. The engines for these rockets are built at Beijing W.J.

"Range of Calt's Long March rockets"

"YF-21C"

-The YF-21 C engine is used in the CZ-4 rocket. The YF-21C engine is a four-engine cluster, but each of them receives the YF-20C designation.

-In the CZ-4's second stage they mounted a YF-24B engine, which is a cluster of a Dayf-20-1 (YF-22) main engine, and a set with four YF-23 (Dayf-21-1) Vernier thrusters.

"YF-24B"

"YF-40A"

"YF-73"

-The YF-73 works with Lox/LH2 and delivers 11 kN. The turbopump is driven by a gas generator. This engine is still in development. The engines are gimballed, so they can oscillate to direct the carrier, in this case the CZ-3.

"YF-77"

"YF-100"

-The YF-100 id the engine for the Long March 5.

-List of engines for this brand: FB-1, YF-1, YF-2A, YF-3, YF-120t, YF-20A, YF-20B, YF-22, YF22, YF22A y 23A, YF-22B, YF-23, YF-25, YF-25/23, YF-40, YF-50t, YF-75.

NOTA = More info at <astronautix.com>

From appendix 10: We have new photos to add to, or replace in the main text.

"YF-1 combustion chamber"

"YF-1 turbo pump"

"YF-2 is a 4 x YF-1 cluster"

“YF-3” (photo S. Grahn)

“YF-40A” (in the CZ-1)

"FG-36 in the CZ-1D's third stage"