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The Franklin O-500 (company designation 6AL-500 and 6A8-215) was an American air-cooled aircraft engine that first ran in the mid-1940s. The engine was of six-cylinder, horizontally-opposed layout and displaced 500 cu in (8 L). The power output was 215 hp (160 kW).

Variants

6AL-500

(alternative designation) 215 hp (160 kW) at 2,500 rpm, with crankcase/prop-shaft extension for pusher installation.

6A8-215-B8F

215 hp (160 kW) at 2,500 rpm, with crankcase/prop-shaft extension for pusher installation.

6A8-215-B9F

same as B8F but with different ignition components.

Applications

• Convair 106 Skycoach
• Piaggio P.136
• Republic RC-3 Seabee
• Waco Aristocraft

Specifications (6AL-500 / 6AB-215-B8F)

Data from Aircraft engines of the World 1950.

General characteristics

• Type: 6-cylinder air-cooled horizontally opposed aircraft piston engine
• Bore: 5 in (127.0 mm)
• Stroke: 4.25 in (108.0 mm)
• Displacement: 500.76 cu in (8.2 L)
• Length: 66.3 in (168.4 cm)
• Width: 33.9 in (86.1 cm)
• Height: 27.4 in (69.6 cm)
• Dry weight: 488 lb (221 kg)

Components

• Valvetrain: 1x OHV exhaust and inlet per cylinder operated by push-rods and rockers
• Fuel system: 1x Marvel-Schebler MA4-5 updraught carburetor
• Fuel type: 80 octane Gasoline
• Oil system: Pressure feed at 35–45 psi (2.4–3.1 bar)
• Cooling system: Air-cooled with cooling fan and shrouds

Performance

• Power output: 215 hp (160 kW) at 2,500 rpm
• Specific power: 0.43 hp/cu in (19.6 kW/L)
• B.m.e.p.: 136 psi (9.38 bar)
• Compression ratio: 7:1
• Specific fuel consumption: 0.5 lb/(hp⋅h) (0.30 kg/kWh)
• Power-to-weight ratio: 0.44 hp/lb (0.72 kW/kg)

See also

Comparable engines

• Lycoming O-540

Related lists

• List of aircraft engines

References

1. Wilkinson, Paul H. (1950). Aircraft engines of the World 1950 (8th ed.). London: Sir Isaac Pitman & Sons Ltd. p. 152-153.

Further reading

• Gunston, Bill (1986). World encyclopaedia of aero engines. P. Stephens. p. 57. ISBN 9780850597172.
• Gunston, Bill (2006). World Encyclopaedia of Aero Engines (5th ed.). Stroud: Sutton Publishing. ISBN 978-0-7509-4479-3.
• Gunston, Bill (1989). World Encyclopaedia of Aero Engines (2nd ed.). Cambridge, England: Patrick Stephens Limited. ISBN 978-1-85260-163-8.

• Franklin aircraft engines
• 1940s aircraft piston engines
• Boxer engines