| Country of origin |  France |
|---|---|
| Designer | Société d'Etudes pour la Propulsion par Réaction |
| Application | Cryogenic Engine Testbed |
| Successor | HM7 |
| Status | Retired |
| Liquid-fuel engine | |
| Propellant | LOX / LH2 |
| Mixture ratio | 5:1 |
| Cycle | Gas-generator |
| Configuration | |
| Chamber | 4 |
| Performance | |
| Thrust | 40 kN (8,992 lbf) |
| Chamber pressure | 24kg/cm2 |
| Specific impulse, vacuum | 412 s (4.04 km/s) |
| Dimensions | |
| Dry mass | 198 kg (437 lb) |
| References | |
| Notes | Testbed engine, never flew |
The HM4 was a first non-American cryogenic rocket engine.[dubious – discuss][1] Developed in France between 1967 and 1969 it never flew into space, was used purely as a testbed for new technologies.[2] Technologies developed in HM4 become a base for HM7 engine used in Ariane.[3]
- ^ SnecMag (8 August 2012). "Snecma rocket engines and Ariane launchers: a powerful, winning combination". Archived from the original on 2014-08-12. Retrieved 16 December 2015.
At the same time, we had developed the HM7 engine, a descendant of the first non-American cryogenic engine (using liquid hydrogen as fuel): the HM4, developed in the 1960s by the Société d'Etudes et de Propulsion par Réaction (SEPR) in Villaroche, the other entity behind the creation of our division.
- ^ Christophe Rothmund. "La cooperation franco-allemande dans le domaine des moteurs-fusées cryotechniques" (PDF) (in French). Snecma, Vernon. pp. 83–85. Archived from the original (PDF) on 4 March 2016. Retrieved 10 August 2014.
- ^ Airbus Air and Defence. "HM-7 and HM-7B Rocket Engine - Thrust Chamber". Retrieved 16 December 2015.