The Piaggio P.X, or Piaggio Stella P.X, was an Italian nine-cylinder radial aircraft engine produced by Rinaldo Piaggio S.p.A. Based on experience license-producing

Gnome et Rhône Gnome et Rhône was a major French aircraft engine manufacturer. Between 1914 and 1918 they produced 25,000 of their 9-cylinder Delta and Le Rhône 110 hp (81 kW) rotary designs, while another 75,000 were produced by various licen ...

designs, the engine was used to power a number of aircraft during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, including the IMAM Ro.37bis and

IMAM Ro.43 The IMAM Ro.43 was an Italian reconnaissance single float seaplane, serving in the Regia Marina between 1935 and 1943. Design and development The Ro.43 was designed to meet a 1933 requirement by the ''Regia Marina'' (the Italian navy) for a c ...

, used extensively by the

Regia Aeronautica The Italian Royal Air Force (''Regia Aeronautica Italiana'') was the name of the air force of the Kingdom of Italy. It was established as a service independent of the Royal Italian Army from 1923 until 1946. In 1946, the monarchy was abolis ...

and

Regia Marina The ''Regia Marina'' (; ) was the navy of the Kingdom of Italy (''Regno d'Italia'') from 1861 to 1946. In 1946, with the Italian constitutional referendum, 1946, birth of the Italian Republic (''Repubblica Italiana''), the ''Regia Marina'' ch ...

respectively.

Design and development

Piaggio acquired a license from

in 1925 for their engines derived from the

Bristol Jupiter The Bristol Jupiter was a British nine-cylinder single-row piston radial engine built by the Bristol Aeroplane Company. Originally designed late in World War I and known as the Cosmos Jupiter, a lengthy series of upgrades and developments turn ...

. The designs proved successful and, using this experience, the company designed a range of related radial engines named "Stella", meaning star. Design was led by the engineer Renzo Spolti. The engines were initially known by their number of cylinders, so the first nine-cylinder model in the range was the P.IX of 1933. However, a progressive number in Roman numerals were used as the design progressed, so the P.IX was followed by the P.X. The Stella P.X was a nine cylinder version of the P.VII. It retained the same bore and stroke as the original Gnome-Rhône designs, and respectively, but was substantially more powerful than the comparable 9K. The engine had a two piece aluminium alloy crankcase and steel barrels for the cylinders and aluminium alloy heads. A Piaggio T2-80 updraught

carburettor A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meterin ...

was fitted. The basic version, the R., had reduction gear, while the R.C. was also equipped with a

compressor A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can transp ...

. The engine powered Italian aircraft that served during

. The

was particularly noteworthy for its performance in the Battles of

Cape Spartivento Domus de Maria is a ''comune'' (municipality) in the Province of South Sardinia in the Italian region Sardinia, located about southwest of Cagliari. Domus de Maria borders the following municipalities: Pula, Santadi, and Teulada. See also ...

and Cape Matapan.

Variants

;P.X R.: Normally aspirated and geared. ;P.X R.C.15: Supercharged and geared, rated at . ;P.X R.C.35: Supercharged and geared, rated at .

Applications

* IMAM Ro.37bis *

IMAM Ro.44 The IMAM Ro.44 was a fighter seaplane developed in Italy, a single seater derivative of the IMAM Ro.43, Ro.43 that first flew in October 1936. While the Ro.43 had serious problems, the Ro.44 was an utter failure. Armed with two 12.7 mm machi ...

Savoia-Marchetti S.73 The Savoia-Marchetti S.73 was an Italian three-engine airliner that flew in the 1930s and early 1940s. The aircraft entered service in March 1935 with a production run of 48 aircraft. Four were exported to Belgium for SABENA, while seven others ...

Savoia-Marchetti S.74 The Savoia-Marchetti S.74 was a four-engine airliner developed by Savoia-Marchetti for ''Ala Littoria''. Design and development The prototype first flew on 16 November 1934. Only three were ever built. Operational history The aircraft were used ...

Savoia-Marchetti SM.81 The Savoia-Marchetti SM.81 ''Pipistrello'' (Italian: bat) was the first three-engine bomber/transport aircraft serving in the Italian ''Regia Aeronautica''.Angelucci and Matricardi 1978, p. 188. When it appeared in 1935, it represented a real s ...

Specifications (R.C.35)

References

Citations

Bibliography

* * * * * * * {{Piaggio aeroengines Aircraft air-cooled radial piston engines 1930s aircraft piston engines P.X