title: Piaggio P.XI
text: # 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)
  