title: Béarn 6
text: # Béarn 6
  
  The Béarn 6 was a six-cylinder air-cooled piston aircraft engine produced in France in the late 1930s, 1940s and early 1950s.
  
  ## Design and development
  
  The Béarn 6 suffered from lack of development and was not a commercial success, most production engines had been removed from service by 1950 due to poor reliability.
  
  ## Applications
  
  * Dassault MD-303
  * Nord 2101 Norazur
  * Dewoitine HD.731
  * SFCA Lignel 16
  * S.C.A.N. 20
  * SNCASO SO.90
  * SNCASE SE-700A
  * S.N.C.A.C. NC.420
  
  ## Specifications (Béarn 6D)
  
  Data from Aircraft Engines of the World 1946.
  
  ### General characteristics
  
  * Type: 6 cylinder, inverted, in-line, four-stroke piston engine
  * Bore: 130 mm (5.12 in)
  * Stroke: 135 mm (5.31 in)
  * Displacement: 10.7 L (653 cu in)
  * Length: 1,500 mm (59.06 in)
  * Width: 450 mm (17.72 in)
  * Height: 825 mm (32.48 in)
  * Dry weight: 290 kg (640 lb)
  * Frontal Area: 0.33 $m^2$ (3.6 sq ft)
  
  ### Components
  
  * Valvetrain: 2 overhead valves per cylinder, pushrod actuated.
  * Supercharger: Gear driven single-speed supercharger with 11.15:1 gear ratio.
  * Fuel system: 1x Zenith 80RGSL-05 updraught carburettor with automatic boost control
  * Fuel type: 87 octane petrol
  * Oil system: Pressure fed at 4.8 bar (70 psi), dry sump
  * Cooling system: Air-cooled
  * Reduction gear: Planetary reduction gear, 0.67:1 ratio adapted for Ratier or Chauvière variable-pitch propellers
  * Starter: Air Equipment 51020 electric inertia starter
  * Ignition: 2 x R.B. GPBA magnetos, 2 x spark plugs per cylinder fed by a shielded ignition harness.
  
  ### Performance
  
  * Power output:
     * Take-off: 310 kW (410 hp) at 2,800rpm, 1,160 mm (46 in) / +3.6 kg (7.9 lb) boost with 100/130 octane petrol
     * Normal: 260 kW (350 hp) at 2,700rpm at 2,000 m (6,600 ft)
     * Cruising: 190 kW (260 hp) at 2,200rpm at 2,000 m (6,600 ft)
  * Specific power: 27.89 kW/L (0.63 hp/cu.in)
  * Compression ratio: 7.2:1
  * Specific fuel consumption: 0.322 kg/(kW h) (0.53 lb/(hp h))
  * Oil consumption: 0.00669 kg/(kW h)(0.011 lb/(hp h))
  * Power-to-weight ratio: 0.968 kW/kg (0.585 hp/lb)
  