| 词条 | HM4 |
| 释义 |
|name = HM4 |image = |image_size = |caption = |country_of_origin= France |date = |first_date = |last_date = |designer = Société d'Etudes pour la Propulsion par Réaction |manufacturer = |purpose = Cryogenic Engine Testbed |associated = CNES |predecessor = |successor = HM7 |status = Retired |type = liquid |oxidiser = Liquid oxygen |fuel = Liquid hydrogen |mixture_ratio = 5.0 |cycle = Gas-generator |pumps = |description = |combustion_chamber=4 |nozzle_ratio = |thrust = {{convert|40|kN|abbr=on|sigfig=4|lk=on}} |thrust_at_altitude= |thrust(Vac) = |thrust(SL) = |thrust_to_weight= |chamber_pressure= 24kg/cm2 |specific_impulse= |specific_impulse_vacuum= {{convert|412|isp|abbr=on}} |specific_impulse_sea_level= |total_impulse = |burn_time = |capacity = |dimensions = |length = |diameter = |dry_weight = 198 kg |used_in = |references = |notes = Testbed engine, never flew }} The HM4 was a first non-American cryogenic rocket engine.{{Check|date=October 2016}}[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] HistoryHM4 evolved from a liquid fuel combustion chamber development projects H2 and H3 led by Société d'Etudes pour la Propulsion par Réaction (SERP) tested between 1961 and 1963 with an intention of using H2 as an upper stage to proposed Diamant Hydrogen variant with a turbopomp derived from Mirage IIIC. However, both projects were abandoned in 1964 and replaced by HM4 engine in 4-chamber configuration producing {{convert|40|kN|abbr=on|sigfig=4|lk=on}} each for a total of {{convert|160|kN|abbr=on|sigfig=4|lk=on}}. First test of a new engine concluded in March 1967. In total 85 trials of HM4 took place with a combined burn time of 2300 seconds, including the longest tested burn time of 350 seconds. Engine was proposed by SERP to be used in ELDO-B project, an evolution of Europa rocket, in a single-chamber configuration to be developed by Rolls-Royce, however project was canceled in 1969 and instead development focused on HM7 which was later used in Ariane 1 upper stage.[2] References1. ^{{cite web|url=http://www.snecma.com/-actualites-snecmag-.html?rubrique51&lang=en&previous=36|archive-url=https://web.archive.org/web/20140812214400/http://www.snecma.com/-actualites-snecmag-.html?rubrique51&lang=en&previous=36|archive-date=2014-08-12|title=Snecma rocket engines and Ariane launchers: a powerful, winning combination|quote=At the same time, we had developed the HM7 engine, a descendent 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.|author=SnecMag|date=8 August 2012|accessdate=16 December 2015|deadurl=yes|df=}} 2. ^1 {{cite web|url=http://www.mirage-buochs.ch/~miragebu/tl_files/MVB/Systeme/SEPR%20844/Cahier33_ROTHMUND.pdf|title=La cooperation franco-allemande dans le domaine des moteurs-fusées cryotechniques|author=Christophe Rothmund|publisher=Snecma, Vernon|language=fr|pages=83–85|format=PDF|accessdate=10 August 2014}} 3. ^{{cite web|url=http://www.space-propulsion.com/launcher-propulsion/rocket-engines/hm7b-rocket-engine.html#moved|title=HM-7 and HM-7B Rocket Engine - Thrust Chamber|author=Airbus Air and Defence|accessdate=16 December 2015}} 3 : Space program of France|Rocket engines using hydrogen propellant|Rocket engines using the gas-generator cycle |
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