The Franklin O-500^{[citation needed]} (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.^[1]

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)