{{Short description|American air-cooled aircraft piston engine designed in the mid-1940s}} <!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. --> {{infobox aero engine |name= O-805/12AC |image = File:Franklin 805.jpg |caption = Franklin O-805 on display at the [[National Museum of the United States Air Force]] |engine_type= 12-cylinder horizontally opposed piston engine |national_origin = |manufacturer= [[Franklin Engine Company]] |first_run={{circa|1945}} |major_applications= |number_built = |developed_from = |developed_into = |variants_with_their_own_articles = }}
The '''Franklin O-805''' (company designation '''12AC''') was an American air-cooled aircraft piston engine, designed in the mid-1940s and was to be used in radio-controlled pilotless drones that were to be guided from an accompanying control plane. Due to project requirement changes and cancellations the engine was not produced.<ref>{{citation|title=Franklin O-805-2|author=NMUSAF|date=June 8, 2015|url=https://www.nationalmuseum.af.mil/Visit/MuseumExhibits/FactSheets/Display/tabid/509/Article/195703/franklin-o-805-2.aspx|publisher=[[National Museum of the United States Air Force]]}}</ref>
A smaller displacement 12-cylinder Franklin engine of 1941 was known as the '''O-595''' or '''12AC-596'''.
==Variants== ===O-805=== ;12AC-806:{{convert|450|hp|kW|abbr=on|0}}0 ;12ACG-806 (XO-805-1):{{convert|456|hp|kW|abbr=on|0}} at 3,200 rpm, geared to 0.632:1. ;12ACGSA-806 (XO-805-3 and O-805-5):{{convert|500|hp|kW|abbr=on|0}} at 3,200 rpm, supercharged and geared to 0.632:1 (XO-805-3), or to 0.587:1 (O-805-5).
===O-595=== ;12AC-596:{{convert|300|hp|kW|abbr=on|0}} at 2,600 rpm
;12ACG-596:{{convert|350|hp|kW|abbr=on|0}} at 3,500 rpm
==Applications (intended)== * [[Interstate XBQ-5]] * [[Interstate XTD2R-1]]
==Survivors== * There is an O-805-2 on display at the [[New England Air Museum]], [[Bradley International Airport]], Windsor Locks, CT <ref>{{Cite web|url=http://neam.org/index.php?option=com_content&view=article&id=1073|title = New England Air Museum}}</ref> * One surfaced and was sold privately in August, 2016, on eBay for US$8500.<ref>{{Cite web|url=http://bringatrailer.com/2016/08/29/13-liter-ww2-drone-engine-super-rare-franklin-0-805/|title = 13 Liter WW2 Drone Engine: Super Rare Franklin 0-805|date = 29 August 2016}}</ref>
==Specifications (12ACGSA-806/XO-805-3)== {{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= |type=12-cylinder air-cooled [[Flat engine|horizontally opposed]] aircraft piston engine |bore={{convert|4.625|in|mm|abbr=on|1}} |stroke={{convert|4.0|in|mm|abbr=on|1}} |displacement={{convert|806.4|cuin|L|abbr=on|1}} |length= |diameter= |width= |height= |weight= |valvetrain=OHV |supercharger= |turbocharger= |fuelsystem= |fueltype= |oilsystem= |coolingsystem=Air-cooled |power={{convert|500|hp|kW|abbr=on|0}} at 3,200 rpm |specpower= |compression= |fuelcon= |specfuelcon= |oilcon= |power/weight=
|designer= |reduction_gear=0.632
|general_other= |components_other= |performance_other= }}
==See also== {{aircontent <!-- include as many lines are appropriate. additional lines/entries with carriage return. --> |see also= |related= |similar aircraft=<!-- similar or comparable aircraft --> |lists=<!-- related lists --> *[[List of aircraft engines]] }}
==References== ;Notes {{reflist}}
==External links== {{Commons category}} *[http://home.comcast.net/~aeroengine/FrkFam.html A table showing the relationship of the military models]
{{Franklin aeroengines}} {{US military piston aeroengines}} {{Aeroengine-specs}}
[[Category:1940s aircraft piston engines]] [[Category:Franklin aircraft engines]] [[Category:Boxer engines]] [[Category:12-cylinder engines]] [[Category:Air-cooled aircraft piston engines]]