Editing Straight-twin engine (section)

== Other uses ==
[[File:Rotax 503 display.JPG|thumb|[[Rotax 503]] aircraft engine]]
Other uses include [[tractor]]s (such as various John Deere models until 1960),<ref name="JohnDeereArt" /> [[snowmobile]]s,<ref name="PS_May1984" /><ref name="SnowmobileServiceManual" /> [[personal watercraft]]s,<ref name="PopMechMay2003FighterJets" /><ref name="FieldAndStreamOct1972" /> and [[all-terrain vehicle]]s.<ref name="AM_TG_Feb2003" /><ref name="BigBore" /><ref name="Best2UpATV" /> Design variations include two-stroke, four-stroke, petrol, diesel,<ref name="OGPEMay2006" /> [[Engine cooling#Air-cooling|air-cooling]], [[Engine cooling#Liquid cooling|water-cooling]], [[naturally aspirated engine|natural aspiration]] and [[turbocharger|turbocharging]].<ref name="AutoEngOct2008" />

[[Ultralight aviation|Ultralight aircraft]], single seat gyro-copters and small homebuilt aircraft have also used straight-twin engines,<ref name="UltralightCliche" /> often using engines originally designed for snowmobiles such as the [[Hirth 2704]] and Cuyuna 430-D.<ref name="PS_May1984" /><ref name="MachineDesignSnowAir" /><ref name="BergerBurr" /> Purpose-built engines for ultralight aircraft include the [[Rotax 503]] and [[Rotax 582]].<ref name="RotaxOperManual" /> Straight-twin engines are sometimes also used in large scale [[radio-controlled aircraft]].<ref name="InTwinSpecSheet" /><ref name="TaplinDesignManufacturingProfiles" />
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