Editing Diesel engine (section)

====Early====
Diesel engines had been used in aircraft before World War II, for instance, in the rigid airship ''[[LZ 129 Hindenburg]],'' which was powered by four [[Daimler-Benz DB 602]] diesel engines,<ref>Kyrill von Gersdorff, Kurt Grasmann: ''Flugmotoren und Strahltriebwerke: Entwicklungsgeschichte der deutschen Luftfahrtantriebe von den Anfängen bis zu den internationalen Gemeinschaftsentwicklungen'', Bernard & Graefe, 1985, {{ISBN|9783763752836}}, p. 14</ref> or in several Junkers aircraft, which had [[Junkers Jumo 205|Jumo 205]] engines installed.<ref name="Reif_2012_103" />

In 1929, in the United States, the [[Packard Motor Company]] developed America's first aircraft diesel engine, the [[Packard DR-980]]—an air-cooled, 9-cylinder [[radial engine]]. They installed it in various aircraft of the era—some of which  were used in record-breaking distance or endurance flights,<ref name="flies_700_miles_1929_05_15_nytimes_com">[https://www.nytimes.com/1929/05/15/archives/flies-700-miles-fuel-cost-468-dieselmotored-packard-plane-goes-from.html "FLIES 700 MILES; FUEL COST $4.68; Diesel-Motored Packard Plane Goes From Michigan to Langley Field in Under Seven Hours. ENGINE HAS NINE CYLINDERS Oil Burner Is Exhibited Before Aviation Leaders, Met for Conference. Woolson Reports on Flight. Packard Motor Stocks Rise,"] May 15, 1929, ''[[New York Times]],'' retrieved December 5, 2022</ref><ref name="packard_2019_05_24_dieselworldmag_com">[https://www.dieselworldmag.com/diesel-engines/first-in-flight/ "The Packard DR-980 Radial Aircraft Diesel"] "First in Flight," "Diesel Engines," May 24, 2019, ''Diesel World'' magazine, retrieved December 5, 2022</ref><ref name="packard_diesel_buhl_earlyaviators_com">[https://www.earlyaviators.com/pimage26.htm "Packard-Diesel Powered Buhl Air Sedan, 1930"] (reproductions of early media articles and photos, with added information), ''Early Birds of Aviation,'' retrieved December 5, 2022</ref><ref name=enginehistory>[http://www.enginehistory.org/Diesels/CH1.pdf Aircraft Engine Historical Society – Diesels] {{webarchive|url=https://web.archive.org/web/20120212213152/http://www.enginehistory.org/Diesels/CH1.pdf |date=2012-02-12 }} Retrieved: 30 January 2009</ref> and in the first successful demonstration of ground-to-air radiophone communications (voice radio having been previously unintelligible in aircraft equipped with spark-ignition engines, due to [[electromagnetic interference]]).<ref name="packard_2019_05_24_dieselworldmag_com" /><ref name="packard_diesel_buhl_earlyaviators_com" /> Additional advantages cited, at the time, included a lower risk of post-crash fire, and superior performance at high altitudes.<ref name="packard_2019_05_24_dieselworldmag_com" />

On March 6, 1930, the engine received an [[Type Certificate|Approved Type Certificate]]—first ever for an aircraft diesel engine—from the [[U.S. Department of Commerce]].<ref name="diesel_aviation_engines_1940_enginehistory_org">Wilkinson, Paul H.: [https://www.enginehistory.org/Piston/Diesels/diesels.shtml "Diesel Aviation Engines,"] 1940, reproduced at Aviation Engine Historical Society, retrieved December 5, 2022</ref> However, noxious exhaust fumes, cold-start and vibration problems, engine structural failures, the death of its developer, and the industrial economic contraction of the [[Great Depression]], combined to kill the program.<ref name="packard_2019_05_24_dieselworldmag_com" />