Editing Ramjet (section)

===Germany===
In 1936, [[Hellmuth Walter]] constructed a test engine powered by [[natural gas]]. Theoretical work was carried out at [[BMW]], [[Junkers]], and [[Deutsche Forschungsanstalt für Luftfahrt|DFL]]. In 1941, [[Eugen Sänger]] of DFL proposed a ramjet engine with a high combustion chamber temperature. He constructed large ramjet pipes with {{convert|500|mm|in}} and {{convert|1000|mm|in}} diameter and carried out combustion tests on lorries and on a special test rig on a [[Dornier Do 17]]Z at flight speeds of up to {{convert|200|m/s|km/h}}. Later, as petrol became scarce in Germany, tests were carried out with blocks of pressed coal dust as a fuel (see e.g. [[Lippisch P.13a]]), which were not successful due to slow combustion.<ref>{{cite book |last=Hirschel |first=Ernst-Heinrich |author2=Horst Prem |author3=Gero Madelung |title=Aeronautical Research in Germany |publisher=Springer |year=2004 |pages=242–243 |isbn=3-540-40645-X}}</ref>