Editing Scramjet (section)

{{Short description|Jet engine where combustion takes place in supersonic airflow}}
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[[File:Scramjet operation en.svg|thumb|300px]] 
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A '''scramjet''' ('''supersonic combustion ramjet''') is a variant of a [[ramjet]] [[airbreathing jet engine]] in which [[combustion]] takes place in [[supersonic]] [[airflow]].  As in ramjets,<ref>{{Cite web|url=https://www.enginehistory.org/Rockets/LorinRamjet/LorinRamjet.shtml|title=Lorin Ramjet|website=www.enginehistory.org}}</ref> a scramjet relies on high vehicle speed to compress the incoming air forcefully before combustion (hence ''ram''jet), but whereas a ramjet decelerates the air to [[speed of sound|subsonic]] velocities before combustion using [[shock cone]]s, a scramjet has no shock cone and slows the airflow using shockwaves produced by its ignition source in place of a shock cone.<ref>''Analysis of Ignition Process in a Scramjet at Low and High Fueling Rates'', Gareth Dunlap, Elias Fekadu, Ben Grove, Nick Gabsa, Kenneth Yu, Camilo Munoz, Jason Burr.</ref> This allows the scramjet to operate efficiently at extremely high speeds.<ref>{{cite journal |title=Supersonic combustion in air-breathing propulsion systems for hypersonic flight. |journal=[[Annual Review of Fluid Mechanics]] |year=2018 |last=Urzay |first=Javier |volume=50 |issue= 1|pages=593–627 |doi=10.1146/annurev-fluid-122316-045217|bibcode=2018AnRFM..50..593U |doi-access=free }}</ref>

Although scramjet engines have been used in a handful of operational military vehicles, scramjets have so far mostly been demonstrated in research test articles and experimental vehicles.