{{Short description|1920s American aircraft piston engine}} {{Use American English|date=February 2026}} <!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. --> {{infobox aero engine |name=R-680 |image=Lycoming R-680-BA Aircraft Engine.jpg |caption=Lycoming R-680 |engine_type=[[Piston]] [[aircraft engine|aero-engine]] |manufacturer=[[Lycoming Engines]] |national_origin=[[United States]] |first_run=1929 |major_applications= {{ubl|[[Beechcraft AT-10 Wichita]] | [[Stinson Reliant]]| [[Curtiss-Wright AT-9]] | [[Stinson Airliner]] }} |produced=1930–1945 out of production |number_built= over 26.000 |developed_from= |variants_with_their_own_articles= |developed_into= }}
The ''' Lycoming R-680''' is a nine-cylinder air-cooled [[radial engine|radial]] engine, the first aero engine produced by [[Lycoming Engines|Lycoming]]. The engine was produced in two types, the E and B series; both are essentially the same. The B4E was available in a trainer version with a front exhaust collector "ring" for use without cylinder air baffles. R-680 received Approved Type Certificate No. 42 on 4 Feb 1930.
==Variants== ;R-680 :Rated at {{convert|210|hp|abbr=on}} at 2,000 rpm. ;R-680B4E :Rated at {{convert|225|hp|abbr=on}} at 2,100 rpm.<ref name="janes">Bridgman 1988</ref> ;R-680BA :Rated at {{convert|240|hp|abbr=on}} ;R-680E3A :Rated at {{convert|285|hp|abbr=on}} at 2,200 rpm.<ref name="janes"/> ;R-680-6 :Rated at {{convert|245|hp|abbr=on}} ;R-680-9 :Rated at {{convert|300|hp|abbr=on}} at 2,200 rpm. ;R-680-13 :Rated at {{convert|300|hp|abbr=on}} at 2,200 rpm.<ref name="janes"/>
==Applications== * [[AT-10 Wichita|Beech AT-10 Wichita]] * [[Boeing-Stearman Model 75|Boeing-Stearman PT-13]] * [[Cessna AT-17|Cessna AT-8/AT-17]] * [[Curtiss-Wright AT-9]] * [[Fleetwings BQ-2]] * [[Spartan NP|Spartan NP-1]] * [[Stinson Airliner]] * [[Stinson Reliant]] * [[Stinson L-1 Vigilant]] * [[Travel Air 4000]] * [[Waco S Series]]
== Specifications (R-680-E3A) == {{pistonspecs| <!-- If you do not understand how to use this template, please ask at [[Wikipedia talk:WikiProject Aircraft]] --> <!-- Please include units where appropriate (main comes first, alt in parentheses). If data are missing, leave the parameter blank (do not delete it). For additional lines, end your alt units with </li> and start a new, fully formatted line with <li> --> |ref=''Jane's Fighting Aircraft of World War II.''<ref name="janes"/> |type=Nine-cylinder air-cooled radial |bore=4 <small>{{frac|5|8}}</small> in (117 mm) |stroke=4 <small>{{frac|1|2}}</small> in (114 mm) |displacement=680 in³ (11.15 litres) |length=37.5 in (953.1 mm) |diameter=43.5 in (1104 mm) |width= |height= |weight=515.46 lb (233.9 kg) |valvetrain=One inlet and one exhaust valve per cylinder at 30 degrees. |supercharger= |turbocharger= |fuelsystem=single-barrel carburetor |fueltype=87 [[octane rating]] [[gasoline]] |oilsystem=Full pressure type |coolingsystem=Air-cooled |power=330 hp (246 kW) at 2,300 rpm at sea level |compression=7:1 |specpower= |fuelcon= |specfuelcon= |oilcon= |power/weight=0.64 hp/lb (1.05 kW/kg) |reduction_gear= }}
==See also== {{aircontent <!-- other related articles that have not already linked: --> |see also=
<!-- designs which were developed into or from this aircraft: --> |related=
<!-- aircraft that are of similar role, era, and capability this design: --> |similar aircraft=
<!-- relevant lists that this aircraft appears in: --> |lists= *[[List of aircraft engines]]
<!-- For aircraft engine articles. Engines that are of similar to this design: --> |similar engines= *[[Bristol Jupiter]] *[[Continental R-670]] *[[Jacobs R-755]] *[[Pratt & Whitney R-985]] *[[Wright R-790 Whirlwind]] <!-- See [[WP:Air/PC]] for more explanation of these fields. --> }}
==References== {{commons category}}
===Notes=== {{reflist}}
===Bibliography=== {{refbegin}} *{{cite book |last=Bridgman |first=Leonard |title= Jane's Fighting Aircraft of World War II|year=1988 |publisher= Crescent Books|location= New York|isbn=0-517-67964-7}} {{refend}} <!--==External links==-->
{{Lycoming aeroengines}} {{US military piston aeroengines}}
[[Category:1920s aircraft piston engines]] [[Category:Aircraft air-cooled radial piston engines]] [[Category:Lycoming aircraft engines|R-680]] [[Category:Nine-cylinder engines]]