Piaggio P.XI
# Piaggio P.XI

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.

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 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.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.100/2v

    (geared, rated altitude 10,000 m (33,000 ft))

## Applications

* Breda Ba.65
* Breda Ba.88
* CANT Z.516
* CANT Z.1007
* Caproni Ca.135
* Caproni Ca.161
* Reggiane Re 2000
* Saab 17C
* Savoia-Marchetti SM.79B
* 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.

### General characteristics

* 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 $m^2$ (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 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.

### 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)
