The Piaggio P.XI was an Italian 14-cylinder radial aircraft engine. The P.XI was a licensed derivative of the French Gnome-Rhône Mistral Major 14K produced in Italy.^[1]

Further development led to the P.XIX. This featured an increased compression ratio from 6:1 to 7:1 and an rpm increase from 2,400 to 2,600.

Variants

P.XI
P.XIbis
P.XI R.C.15: (geared, rated altitude 1,500 m (4,900 ft))
P.XI R.C.30: (geared, rated altitude 3,000 m (9,800 ft))
P.XI R.C.40D: ^[2]
P.XI R.C.40S: 740 kW (1,000 PS) (geared, rated altitude 4,000 m (13,000 ft)), opposite rotation to 40D.
P.XI R.C.40bis: (geared, rated altitude 4,000 m (13,000 ft))
P.XI R.2C.40: 740 kW (1,000 PS), (geared, rated altitude 4,000 m (13,000 ft)), two-speed supercharger.
P.XI C.40: (direct drive, rated altitude 4,000 m (13,000 ft))
P.XI R.C.44: (geared, rated altitude 4,400 m (14,400 ft))
P.XI R.C.50: (geared, rated altitude 5,000 m (16,000 ft))
P.XI R.C.60: (geared, rated altitude 6,000 m (20,000 ft))
P.XI R.C.72: (geared, rated altitude 7,200 m (23,600 ft))
P.XI R.C.l00
P.XI R.C.100/2v: (geared, rated altitude 10,000 m (33,000 ft))

Applications

Data from Italian Civil & Military Aircraft 1930-1945 and Aircraft Engines of the World 1945.^[3]^[4]

Type: 14-cylinder radial engine
Bore: 146 mm (5.75 in)
Stroke: 165 mm (6.50 in)
Displacement: 38.6 L (2,356 cu in)
Length: 1,700 mm (66.9 in)
Diameter: 1,328 mm (52.3 in)
Dry weight: 650 kg (1,433 lb)
Frontal Area: 1.39 m² (15.0 sq ft)

Valvetrain: 2 x overhead valves per cylinder operated by rockers and pushrods
Supercharger: Centrifugal compressor, geared to 7.9:1
Fuel system: 1 x Piaggio T2-100 dual downdraught carburettor with automatic boost and mixture control
Fuel type: 87 octane
Oil system: Pressure fed at 483 kPa (70 psi), dry sump
Cooling system: Air
Reduction gear: Epicyclic reduction gear ratio 0.62:1
Starter: Garelli compressed air starter
Ignition: 2 x Marelli MF14 magnetos, 2 x spark plugs per cylinder fed by a shielded ignition harness.

^ Gunston 1989, p.110.
^ Grey, C.G.; Bridgman, Leonard (1938). Jane's All the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. :740 kW (1,000 PS) (geared, rated altitude 4,000 m (13,000 ft))
^ Thompson, Jonathan (1963). Italian Civil & Military Aircraft 1930-1945. New York: Aero Publishers Inc. ISBN 0-8168-6500-0. LCCN 63-17621.
^ Wilkinson, Paul H. (1945). Aircraft engines of the World 1945 (2nd ed.). London: Paul H. Wilkinson. pp. 306–307.

Thompson, Jonathan (1963). Italian Civil & Military Aircraft 1930-1945. New York: Aero Publishers Inc. ISBN 0-8168-6500-0. LCCN 63-17621.
Wilkinson, Paul H. (1945). Aircraft engines of the World 1945 (2nd ed.). London: Paul H. Wilkinson. pp. 306–307.
Grey, C. G.; Bridgman, Leonard (1938). Jane's All the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd.
Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9

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