View source for 2si 690

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{|{{Infobox Aircraft Begin
| name=2si 690
| image=
| caption=
}}{{Infobox Aircraft Engine
|type= [[Two-stroke]] [[aircraft engine]]
|manufacturer=[[2si]]
|national origin=[[United States]]
|first run=
|major applications=
|produced=
|number built=
|program cost=
|unit cost=
|developed from=
|variants with their own articles=
}}
|}
The '''2si 690''' is a family of in-line three cylinder, liquid-cooled, [[two-stroke]], dual ignition, [[aircraft engine]]s that were designed for [[ultralight aircraft]].<ref name="Cliche">Cliche, Andre: ''Ultralight Aircraft Shopper's Guide'' 8th Edition, page G-3 Cybair Limited Publishing, 2001. {{ISBN|0-9680628-1-4}}</ref>
The basic engine was originally designed and produced by [[JLO-Motorenwerke]] of [[Germany]] and was later acquired by the [[AMW Cuyuna Engine Company]] of [[Beaufort, South Carolina]] and marketed under the ''Cuyuna'' brand name. Later the engine was marketed by Cuyuna under the [[Two Stroke International]] (2si) brand. Cuyuna no longer markets engines for aircraft use although the 690 is still in production as an industrial and marine engine.<ref name="Cliche" /><ref name="About2si">{{cite web|url = http://www.2si.com/2si_company_profile.htm|title = 2si Company Profile|accessdate = 2010-02-16|year = n.d.|archiveurl = https://web.archive.org/web/20100115032358/http://www.2si.com/2si_company_profile.htm|archivedate = 2010-01-15|url-status = dead}}</ref><ref name="690L70">{{cite web|url = http://www.2si.com/690l-70_690al-70_spec.htm|title = Engine Models 690L – 70 and 690AL-70 Industrial Configuration|accessdate = 2010-02-22|year = n.d.|archiveurl = https://web.archive.org/web/20100115163459/http://www.2si.com/690l-70_690al-70_spec.htm|archivedate = 2010-01-15|url-status = dead}}</ref><ref name="690L70Marine">{{cite web|url = http://www.2si.com/marine__engine__model__690lspec.htm|title = Marine Engine Model 690-L70|accessdate = 2010-02-22|year = n.d.|archive-url = https://archive.today/20130116004218/http://www.2si.com/marine__engine__model__690lspec.htm|archive-date = 2013-01-16|url-status = dead}}</ref>
==Development==
The 690 is a conventional three-cylinder engine that weighs {{convert|89|lb|kg|0|abbr=on}} in its L70 aircraft and marine versions. The aircraft engine features dual [[capacitor discharge ignition]] (single in the marine and industrial versions), reed valve porting, tuned exhaust system, three slide venturi-type [[carburetor]]s, liquid cooling, fuel pumps, a cast iron cylinder liner, ball, needle and roller bearings throughout. The aircraft version was offered with an optional gearbox reduction dive system and a centrifugal clutch. The current industrial and marine version has an available gearbox with ratios of 2.04, 2.65 or 3.06:1. Starting is electric start only.<ref name="Cliche" /><ref name="690L70" />
<!-- ==Operational history== -->
==Variants==
;690-L70 aircraft engine
:Gasoline aircraft engine with triple carburetors, {{convert|70|hp|kW|0|abbr=on}} at 6250 rpm, weight {{convert|89|lb|kg|0|abbr=on}}, out of production.<ref name="Cliche" />
;690L-70 industrial and marine engine
:Gasoline industrial and marine engine, triple carburetors, {{convert|70|hp|kW|0|abbr=on}} at 6250 rpm, weight {{convert|89|lb|kg|0|abbr=on}}, electric starter mounted on the accessory cover end. Still in production.<ref name="690L70" /><ref name="690L70Marine" />
;690AL-70 industrial and marine engine
:Gasoline industrial and marine engine, triple carburetors, {{convert|70|hp|kW|0|abbr=on}} at 6250 rpm, weight {{convert|89|lb|kg|0|abbr=on}}, electric starter mounted on the power take-off end. Still in production.<ref name="690L70" /><ref name="690L70Marine" />
==Applications==
;Aircraft
*[[RagWing RW11 Rag-A-Bond]]
*[[RagWing RW19 Stork]]
*[[RagWing RW22 Tiger Moth]]
*[[Sky Science PowerHawk]]
*[[St Andrews Viking]]
*[[Viking Aircraft Viking II]]
==Specifications (690-L70 aircraft engine) ==
{{pistonspecs|
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|ref=Cliche<ref name="Cliche" /> & 2si<ref name="690L70" />
|type=Three-cylinder, two-stroke aircraft engine
|bore={{convert|69.5|mm|in|2|abbr=on}}
|stroke={{convert|60|mm|in|2|abbr=on}}
|displacement=684 cc (41.7 cu in)
|length={{convert|21.6|in|mm|0|abbr=on}}
|diameter=
|width={{convert|19.05|in|mm|0|abbr=on}}
|height={{convert|13.9|in|mm|0|abbr=on}}
|weight={{convert|89|lb|kg|0|abbr=on}}
|valvetrain=reed valve porting
|supercharger=
|turbocharger=
|fuelsystem=
|fueltype=Minimum 92 octane
|oilsystem=premixed oil and fuel at 50:1
|coolingsystem=liquid cooled
|power={{convert|70|hp|kW|0|abbr=on}} at 6250 rpm
|specpower=
|compression=
|fuelcon=5.1 US gal/h (19.3 L/h) at 75% power
|specfuelcon=
|oilcon=
|power/weight=
|designer=
|reduction_gear=optional gearbox
|general_other=
|components_other=
|performance_other=
}}
==See also==
{{aircontent
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|see also=
*[[List of aircraft engines]]
*[[Hirth 3701]]
*[[Rotax 618]]
|related=<!-- related developments -->
|similar aircraft=<!-- similar or comparable aircraft -->
|lists=
}}
==References==
{{Reflist}}
<!-- ==External links== -->
{{2si}}
[[Category:Two-stroke aircraft piston engines]]
[[Category:Straight-three engines]]