Béarn 6
# 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)
