Piaggio P.XI

P.XI
Preserved Piaggio P.XI
Type	Radial engine
Manufacturer	Piaggio
Developed from	Gnome-Rhône Mistral Major

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] Isotta Fraschini also produced a version of the 14K called the K.14.

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

• Breda Ba.65
• Breda Ba.88
• CANT Z.1007
• Caproni Ca.135
• Caproni Ca.161
• Reggiane Re 2000
• Saab 17C
• Savoia-Marchetti SM.79-II
• Savoia-Marchetti SM.84

Specifications (P.XI R.C.40)

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

General characteristics

• Type: 14-cylinder radial engine
• Bore: 146 mm (5.748 in)
• Stroke: 165 mm (6.496 in)
• Displacement: 38.673 l (2,360.0 cu in)
• Length: 1,700 mm (66.93 in)
• Diameter: 1,328 mm (52.28 in)
• Dry weight: 650 kg (1,433 lb)
• Frontal Area: 1.39 m² (15.0 sq ft)

Components

• 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 482.6 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.

Performance

• Power output:
  
• Take-off: 1,000 PS (735 kW) at 2,200rpm
• Military: 1,000 PS (735 kW) at 2,200rpm at 4,000 m (13,000 ft)
• Cruising: 1,000 PS (735 kW) at 1,800rpm at 4,000 m (13,000 ft)
• Specific power: 19.1 kW/l (0.49 hp/cu in)
• Compression ratio: 6.0:1
• Specific fuel consumption: 0.292 kg/kW/hr (0.48 lb/hp/hr)
• Oil consumption: 0.0134 kg/k/w/hr (0.022 lb/hp/hr)
• Power-to-weight ratio: 1.15 kW/kg (0.699 hp/lb)

See also

Related development

• Gnome-Rhône Mistral Major

Related lists

• List of aircraft engines

References

Notes

1. Gunston 1989, p.110.
2. 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))
3. Thompson, Jonathan (1963). Italian Civil & Military Aircraft 1930-1945. New York: Aero Publishers Inc. ISBN 0-8168-6500-0. LCCN 63-17621.
4. Wilkinson, Paul H. (1945). Aircraft engines of the World 1945 (2nd ed.). London: Paul H. Wilkinson. pp. 306–307.

Bibliography

• 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