Piaggio P.X
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 designs, the engine was used to power a number of aircraft during World War II, including the IMAM Ro.37bis and IMAM Ro.43, used extensively by the Regia Aeronautica and Regia Marina respectively.
Design and development
Piaggio acquired a license from Gnome et Rhône in 1925 for their engines derived from the Bristol Jupiter.[1] The designs proved successful and, using this experience, the company designed a range of related radial engines named "Stella", meaning star.[2] The design was led by the engineer Renzo Spolti.[3] 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 was used as the design progressed, so the P.IX was followed by the P.X.[2]
The Stella P.X was a nine-cylinder version of the P.VII.[4] It retained the same bore and stroke as the original Gnome-Rhône designs, 146 mm (5.7 in) and 165 mm (6.5 in) respectively, but was substantially more powerful than the comparable 9K.[3] The engine had a two piece aluminium alloy crankcase, steel barrels for the cylinders and aluminium alloy heads. A Piaggio T2-80 updraught carburettor was fitted.[5] The basic version, the R., had reduction gear, while the R.C. was also equipped with a compressor.[2]
The engine powered the Italian aircraft that served during World War II.[6] The IMAM Ro.43 was particularly noteworthy for its performance in the Battles of Cape Spartivento and Cape Matapan.[7]
Variants
- P.X R.
- Normally aspirated and geared.
- P.X R.C.15
- Supercharged and geared, rated at 1,500 m (4,900 ft).
- P.X R.C.35
- Supercharged and geared, rated at 3,500 m (11,500 ft).
Applications
- IMAM Ro.37bis
- IMAM Ro.43
- IMAM Ro.44
- Savoia-Marchetti S.73
- Savoia-Marchetti S.74
- Savoia-Marchetti SM.81
Specifications (R.C.35)
Data from Wilkinson, 1945 [5]
General characteristics
- Type: 9-cylinder, single row, air cooled radial engine
- Bore: 146 mm (5.7 in)
- Stroke: 165 mm (6.5 in)
- Displacement: 24.9 L (1,519 in3)
- Length: 1,408 mm (55.4 in)
- Diameter: 1,280 mm (50 in)
- Dry weight: 430 kg (950 lb)
Components
- Valvetrain: 2 x overhead valves per cylinder operated by rockers and pushrods
- Supercharger: Centrifugal compressor
- Fuel type: 87 Octane petrol
- Cooling system: Air-cooled
Performance
- Power output:
- Take-off: 640 hp (477 kW) at 2,250 rpm
- Cruise: 450 hp (336 kW) at 1,800 rpm at 3,500 m (11,500 ft)
- Compression ratio: 6.0:1
- Specific fuel consumption: 300 g/kWh (0.48 lb/(hp·h))
- Oil consumption: 8 g/kWh (0.018 lb/(hp·h))
See also
Related development
Comparable engines
Related lists
References
Citations
- ^ Gunston 1986, p. 125.
- ^ a b c "PXI RC40 engine". Museo Piaggio. Archived from the original on 26 August 2017. Retrieved 27 March 2020.
- ^ a b Angle 1939, p. 584.
- ^ Wilkinson 1945, p. 60.
- ^ a b Wilkinson 1945, p. 302.
- ^ Green 1967, p. 111.
- ^ Sadkovich 1994, p. 98.
Bibliography
- Angle, Glenn Dale (1939). Aerosphere. New York.
{{cite book}}: CS1 maint: location missing publisher (link) - Green, William (1967). War Planes of the Second World War: Volume Six – Floatplanes. London: Macdonald. ISBN 978-3-56014-509-1.
- Gunston, Bill (1978). The Illustrated Encyclopedia of Combat Aircraft of World War II. London: Salamander Books. ISBN 978-0-86101-017-2.
- Gunston, Bill (1986). World Encyclopedia of Aero Engines. London: Guild Publishing. ISBN 978-0-85059-717-2.
- Sadkovich, James (1994). The Italian Navy in World War II. Westport: Greenwood Press. ISBN 978-0-31328-797-8.
- Thompson, Jonathon W. (1963). Italian Civil and Military Aircraft 1930–1945. USA: Aero Publishers Inc. ISBN 978-0-81686-500-0.
{{cite book}}: ISBN / Date incompatibility (help) - Wilkinson, Paul Howard (1945). Aircraft Engines of the World. New York: Paul H. Wilkinson. Retrieved 27 March 2020.