| Stella P.X | |
| Engine Type: | Air cooled radial |
| Designer: | Renzo Spolti |
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.
Piaggio acquired a license from Gnome et Rhône in 1925 for their engines derived from the Bristol Jupiter. The designs proved successful and, using this experience, the company designed a range of related radial engines named "Stella", meaning star.[1] The 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 was 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, 146mm and 165mm respectively, but was substantially more powerful than the comparable 9K. 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. The basic version, the R., had reduction gear, while the R.C. was also equipped with a compressor.
The engine powered the Italian aircraft that served during World War II. The IMAM Ro.43 was particularly noteworthy for its performance in the Battles of Cape Spartivento and Cape Matapan.
