{{Short description|12-cylinder inverted-V aircraft engine}} {{infobox aero engine |name= Delta |image = Isotta Fraschini Delta RC131.jpg |caption = Preserved Delta RC131 |engine_type= V12 piston engine |national_origin = |manufacturer= Isotta Fraschini |first_run=1927 |major_applications= |number_built = {{circa|3,300}} |developed_from = |developed_into = |variants_with_their_own_articles = }}

The '''Delta''' was a 12-cylinder inverted-V aircraft engine built by Isotta Fraschini prior to and during World War II.<ref>Gunston 1989, p.82.</ref>

==Design and development== The Delta is a fairly rare example of a large air-cooled inline engine, which normally have cooling problems with the rearmost cylinders. It produced about 750&nbsp;hp in common versions, although others were rated up to 900&nbsp;hp. The Delta was not widely used, although it could be found on a number of production aircraft and some advanced prototypes.

The engine included a number of otherwise advanced features. For instance, the valves were powered by dual overhead cams driven by power shafts at the rear of the engine. Exhaust ports were arranged to exit toward the middle of the engine, one cylinder bank being the mirror of the other, allowing the piping to be ganged below the engine nacelle.

==Variants== ; Delta R.C.20/55 ID-IS ; Delta R.C.21/60 ; Delta R.C.35 ; Delta R.C.35 I ; Delta R.C.35 IS ; Delta R.C.40 IS ; Delta R.C.40 ID-IS ; Delta R.C.48 ; Delta III R.C.40 ; Delta IV R.C.17/50

==Applications== [[File:CANT z515-i.jpg|thumb|Delta-powered CANT Z.515 floatplane]] *Ambrosini SAI.107 *Ambrosini SAI.207 prototype *Ambrosini SAI.403 prototype *CANT Z.515 *Caproni Ca.313 *Caproni Ca.314 *Caproni Ca.331 *Caudron C.714 (C.760) prototype *Henschel Hs 129 prototype *Reggiane Re.2001 prototype * Savoia-Marchetti SM.86

==Specifications (Delta RC35-IDS)== thumb|Frontal view of sectioned engine {{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=''Aircraft engines of the World.''<ref>Wilkinson 1945, p. 286.</ref> |type=12-cylinder air-cooled 60 degree inverted vee |bore={{convert|132|mm|in|abbr=on}} |stroke={{convert|160|mm|in|abbr=on}}<!-- Articulated connecting rods, second dimension not given in source) --> |displacement={{convert|26.7|L|cuin|abbr=on}} |length= {{convert|2000|mm|in|1|abbr=on}} |width= {{convert|840|mm|in|1|abbr=on}} |height= {{convert|883|mm|in|1|abbr=on}} |weight=510 kg (1,124 lb) |valvetrain= Two poppet valves per cylinder, sodium cooled exhaust valves, double overhead camshafts |supercharger=Single-stage, single-speed centrifugal type supercharger, gear ratio 9.8:1 |fuelsystem=Four Isotta Fraschini downdraft carburetors |fueltype=80/87 octane petrol (aviation gasoline) |oilsystem=Dry sump, double scavenge pump, single pressure pump |coolingsystem=Air-cooled |power=<li> :*{{convert|770|hp|kW|abbr=on|order=flip}} at 2,600 rpm (take off) :*{{convert|750|hp|kW|abbr=on|order=flip}} at 2,600 rpm at {{convert|4000|m|ft|abbr=on|}} |specpower=21.5 kW/L (0.47 hp/in³) |compression=6.4:1 |fuelcon= |specfuelcon= 270 grams/hp*hour maximum, 250 grams/hp*hour cruise (70%) |oilcon= |power/weight=1.1 kW/kg (0.68 hp/lb) |reduction_gear= Ratio 0.64:1 }}

==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 as 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= *Allison V-1710 *Hispano-Suiza 12X *Rolls-Royce Merlin

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==References== {{Commons category}} {{reflist}}

===Bibliography=== {{refbegin}} *Gunston, Bill. ''World Encyclopedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989. {{ISBN|1-85260-163-9}} *''Jane's Fighting Aircraft of World War II''. London. Studio Editions Ltd, 1989. {{ISBN|0-517-67964-7}} * Wilkinson, Paul H. ''Aircraft engines of the World 1945''. New York, Paul H. Wilkinson, 1945. {{refend}}

{{Isotta Fraschini aeroengines}}

Delta Category:Aircraft air-cooled V piston engines Category:1920s aircraft piston engines Category:Inverted V12 aircraft engines