Franklin O-500
# Franklin O-500

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)
