:Piaggio Stella P.IX

Piaggio acquired a license from Gnome et Rhône in 1925 for their engines derived from the Bristol Jupiter and, in 1933, brought out a developed version, created under the direction of engineer Renzo Spolti.{{sfn|Angle|1939|page=584}} The engine had nine cylinders and was therefore named P.IX. It was one of a range of Piaggio radial engines named Stella, or Star, all based on the same radial design.{{sfn|Gunston|1986|page=125}}

The engine had cylinders that had steel barrels and aluminium heads. Aluminium alloy pistons were connected to a split crankshaft via articulated connecting rods. The valves were enclosed.{{sfn|Angle|1941|page=143}} Each cylinder retained the same bore and stroke as the Gnome-Rhône 9K, {{convert|146|mm|in|lk=on}} and {{convert|165|mm|in|abbr=on}} respectively.{{sfn|Angle|1939|page=584}} However, it was more powerful and was rated at {{convert|600|hp|kW|0|lk=on}} when fitted with a supercharger.{{sfn|S.A. Piaggio e.C.|1939}}

The engine was used to power aircraft that served during the Second Italo-Ethiopian War, Spanish Civil War and Second World War, including one hundred and forty Savoia-Marchetti SM.81s, a Regia Aeronautica transport, and the majority of the production of the IMAM Ro.37bis reconnaissance aircraft. Most had retired by 1943.{{sfn|Passingham|1977|page=182}}{{sfn|Thompson|1963|page=199}}

;P.IX R.: Normally aspirated and geared.{{sfn|Gunston|1986|page=125}}

;P.IX R.C.: Supercharged and geared.{{sfn|Gunston|1986|page=125}}

;P.IX R.C.10: Supercharged and geared, rated at {{convert|1000|m|ft|abbr=on}}.{{sfn|Abate|Alegi|1992|page=245}}

;P.IX R.C.40: Supercharged and geared, rated at {{convert|4000|m|ft|abbr=on}}.{{sfn|Angle|1941|page=143}}

• CANT Z.504{{sfn|Thompson|1963|page=55}}
• CANT Z.506 prototype{{sfn|Thompson|1963|page=62}}
• Caproni Ca.131{{sfn|Abate|Alegi|1992|page=244}}
• Caproni Ca.132{{sfn|Abate|Alegi|1992|page=245}}
• Caproni Ca.301{{cite web|title=AP.1|website=Airwar|url=http://www.airwar.ru/enc/aww2/ap1.html|access-date=3 March 2020}}
• Caproni Ca.305
• Caproni CH.1{{sfn|Green|Swanborough|1994|page=108}}
• IMAM Ro.37bis{{sfn|Thompson|1963|page=199}}
• IMAM Ro.43 prototype{{sfn|Fitzsimmons|1971|page=2217}}
• Piaggio P.10bis{{sfn|Thompson|1963|page=222}}
• Piaggio P.16{{sfn|Thompson|1963|page=220}}
• Savoia-Marchetti S.73{{sfn|Thompson|1963|page=258}}
• Savoia-Marchetti SM.79 prototype{{sfn|Thompson|1963|page=260}}
• Savoia-Marchetti SM.81{{sfn|Passingham|1977|page=182}}

{{pistonspecs|

|ref=Piaggio, 1939{{sfn|S.A. Piaggio e.C.|1939}}

|type= 9-cylinder, single row, air cooled radial engine

|bore= {{convert|146|mm|in|abbr=on}}

|stroke= {{convert|165|mm|in|abbr=on}}

|displacement= {{convert|24.9|L|in3|0|abbr=on}}

|length= {{convert|1050|mm|in|abbr=on}}

|diameter= {{convert|1408|mm|in|abbr=on}}

|width=

|height=

|weight={{convert|430|kg|lb|abbr=on}}

|valvetrain= 2 x overhead valves per cylinder operated by rockers and pushrods

|supercharger= Centrifugal compressor

|turbocharger=

|fuelsystem=

|fueltype= 87 Octane petrol

|oilsystem=

|coolingsystem= Air-cooled

|power=

• Take-off: {{convert|610|hp|kW|0|abbr=on}} at 2100 rpm
• Cruise: {{convert|600|hp|kW|0|abbr=on}} at 2100 rpm at {{convert|4000|m|ft|0|abbr=on}}

|specpower=

|compression= 6.0:1

|fuelcon=

|specfuelcon=

|oilcon=

|power/weight=

|designer=

|reduction_gear=

|general_other=

|components_other=

|performance_other=

}}

{{aircontent

|see also=

|related=

• Gnome-Rhône 9K

|similar aircraft=

|lists=

• List of aircraft engines

|similar engines=

• Alfa Romeo 125
• Nakajima Kotobuki
• Pratt & Whitney R-1340 Wasp

}}

{{reflist}}

• {{cite book |last1=Abate |first1=Rosario |last2=Alegi |first2=Gregory |last3=Apostollo |first3=Giorgio |title=Aeroplani Caproni: Gianni Caproni and his aircraft, 1910-1983 |date=1992 |publisher=Associazione Museo dell'Aeronautica G. Caproni |place=Trento |oclc=237798156 |ref=CITEREFAbateAlegi1992}}
• {{cite book |first=Barnard |last=Fitzsimmons |title=The Illustrated Encyclopedia of 20th Century Weapons and Warfare |volume=20 |place=New York |publisher=Columbia House |year=1971 |oclc=8842839}}
• {{cite book |first=Glenn Dale |last=Angle |title=Aerosphere |year=1939 |place=New York |publisher=Aircraft Publications}}
• {{cite book |first=Glenn Dale |last=Angle |title=Modern Aircraft Engines |place=New York City |publisher=Aircraft Publications |year=1941 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015006075827 |oclc=658901703}}
• {{cite book |first=Bill |last=Gunston|title=World Encyclopedia of Aero Engines |place=London |publisher=Guild Publishing |year=1986 |isbn=978-1-85260-509-4 }}
• {{cite journal |last=Passingham |first=Malcolm |title=Savoia-Marchetti SM81 |journal=Aircraft Illustrated |date=May 1977 |volume=10 |number=5 |pages=182–187}}
• {{cite book |author=S.A. Piaggio e.C. |title=Instruzione per l'uso del motore P IX R C 40 |place=Rome |publisher=Ministero dell’Aeronautica |year=1939 }}
• {{cite book |last1=Green |first1=William |first2=Gordon |last2=Swanborough |title=The Complete Book of Fighters: An Illustrated Encyclopedia of Every Fighter Aircraft Built and Flown |publisher=SMITHMARK Publishers |place=New York |date=1994 |isbn=0-8317-3939-8}}
• {{cite book |last=Thompson |first=Jonathon W. |title=Italian Civil and Military Aircraft 1930–1945 |year=1963 |publisher=Aero Publishers Inc. |location=USA |isbn=0-8168-6500-0}}

{{Piaggio aeroengines}}

Category:1930s aircraft piston engines

Category:Air-cooled aircraft piston engines

P.IX