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Franklin 6 series

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Franklin 6 series

The Franklin 6 is a series of air-cooled aircraft and helicopter engines of flat-6 configuration, produced from the 1930s to the 1970s, that found widespread use in helicopters and some light aircraft, (Military designation O-335, O-405 and O-425), as well as in the 1948 Tucker Sedan (with the engine modified for water cooling).

Contents

Variants

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Applications

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Specifications (6ACV-403)

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General characteristics

  • Type: 6-cylinder air-cooled horizontally opposed vertically mounted helicopter piston engine
  • Bore: 4.625 in (117.5 mm)
  • Stroke: 4 in (101.6 mm)
  • Displacement: 403 cu in (6.60 l)
  • Width: 33.7 in (856.0 mm)
  • Height: 43.4 in (1,102.4 mm)
  • Dry weight: 458 lb (207.7 kg)

    • Components

  • Valvetrain: OHV, 1x inlet valve, 1x exhaust valve operated by pushrods
  • Fuel system: 2x Bendix-Stromberg PS-5C pressure updraught carburettors
  • Fuel type: 80 Octane gasoline
  • Oil system: 120 S.U. secs (25.1 cSt) grade pressure fed at 55 psi (379,212 Pa), dry sump
  • Cooling system: Air-cooled
  • Delco-Remy 108567-541 vertical geared electric starter motor

    • Performance

  • Power output: 245 hp (182.7 kW) at 3,275 rpm for take-off
  • Specific power: 0.61 hp/(sq in) (27.758 kW/L)
  • Compression ratio: 7:1
  • Specific fuel consumption: 0.5 lb/(hp h) (0.304 kg/(kW h), 225 US gal/(hp h)) cruising
  • Oil consumption: 0.015 lb/(hp h) (0.09 kg/(kW h), 7 US gal/(hp h)) cruising
  • Power-to-weight ratio: 0.357 hp/lb (0.587 kW/kg)

    • References

    Franklin 6 series Wikipedia
    (Text) CC BY-SA