{{Short description|American piston aircraft engine}} {{Use dmy dates|date=December 2022}} {{Use American English|date=December 2022}} <!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. --> {{infobox aero engine |name= O-150/4AC |image = File:Franklin 4 AC-150-A (1938) aircraft engine - San Diego Air & Space Museum annex Gillespie Field.jpg |caption = 4AC-150 engine on display at the [[San Diego Air & Space Museum]] |engine_type= [[Piston]] [[aircraft engine]] |national_origin = United States |manufacturer= [[Franklin Engine Company]] |first_run= 1938 |major_applications= |number_built = |developed_from = |developed_into = |variants_with_their_own_articles = }}

The '''Franklin O-150''' (company designation '''4AC-150''') was an American air-cooled aircraft engine of the late 1930s. The engine was of [[Flat-four engine|four-cylinder, horizontally-opposed layout]] and [[Engine displacement|displaced]] {{convert|150|cuin|L|abbr=on|0}}. The power output was nominally {{convert|40|hp|kW|abbr=on|0}}.

==Applications== *[[Aeronca 50 Chief]] *[[Bartlett Zephyr]] *[[Clutton-Tabenor FRED]] *[[Fetterman Chickadee]] *[[Payne MC-7 pusher]] *[[Piper J-3 Cub]] *[[Rose Parakeet]] *[[Taylorcraft B|Taylorcraft BF-65]] *[[Taylorcraft L-2]]

==Engines on display== *[[Aerospace Museum of California]] - Franklin 0-150 (4AC-150)

==Specifications (4AC-150)== [[File:Air Zoo December 2019 150 (Franklin Model 4AC150).jpg|thumb|O-150 on display at the [[Air Zoo]]]] {{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 all the World's Aircraft 1938.''<ref name=JAWA1938>{{cite book |title=Jane's all the World's Aircraft 1938 |editor1-last=Grey |editor1-first=C.G. |year=1938 |publisher=Sampson Low, Marston & company, ltd |location=London |editor2-last=Bridgman|editor2-first=Leonard|page=85d}}</ref> |type=4-cylinder air-cooled [[horizontally opposed]] aircraft piston engine |bore={{convert|3.625|in|abbr=on}} |stroke={{convert|3.625|in|abbr=on}} |displacement={{convert|149.6|cuin|L|abbr=on|2}} |length= {{convert|27.5|in|cm|abbr=on}} |diameter= |width={{convert|34.375|in|cm|abbr=on|1}} |height={{convert|18.375|in|cm|abbr=on|1}} |weight={{convert|155|lb|abbr=on}} |valvetrain=Pushrod and rocker operated overhead valves. One intake, one exhaust |supercharger= |turbocharger= |fuelsystem=Stromberg NA-S2 updraught carburetor |fueltype=[[Octane rating|70 Octane]] gasoline |oilsystem=Wet sump full pressure system |coolingsystem=Air-cooled |power={{convert|40|hp|abbr=on}} at 1,875 rpm |specpower= |compression=6.66:1 |fuelcon={{convert|4.4|USgal/h|L/h|abbr=on}} |specfuelcon=0.54 lb/hp/h |oilcon= |power/weight= }}

==See also== {{aircontent <!-- include as many lines are appropriate. additional lines/entries with carriage return. --> |see also= |related= |similar engines= *[[Lycoming O-145]] |similar aircraft=<!-- similar or comparable aircraft --> |lists=<!-- related lists --> *[[List of aircraft engines#Franklin|List of aircraft engines]] }}

==References== {{Commons category}} ;Notes {{reflist}} ;Bibliography {{refbegin}} * Gunston, Bill. (1986) ''World Encyclopedia of Aero Engines''. Patrick Stephens: Wellingborough. p.&nbsp;57 {{refend}}

{{Franklin aeroengines}} {{US military piston aeroengines}}

[[Category:Franklin aircraft engines]] [[Category:1930s aircraft piston engines]] [[Category:Boxer engines]] [[Category:Four-cylinder engines]] [[Category:Air-cooled aircraft piston engines]]