Franklin 6V4
1946 - 1970
Description
The Franklin 6V4 is an air cooled 6-cylinder boxer engine, built by Aircooled Motors Inc., in Syracuse in the state of New York. It It has been mainly used in the small helicopter Bell 47.
Technical specifications
| Manufacturer | Aircooled Motors, Syracuse, New York, USA, from 1946 to 1970 |
| Type | 6V4-200-C32 |
| Description | aircraft engine with 6-opposed cylinders (boxer-type), aluminium alloy crankcase composed of two parts with 5 main bearings, cylinders with integrated aluminium alloy head and internal hot-forced steel liners |
| Stroke | 89 mm |
| Bore | 114 mm |
| Displacement | 5.5 litri |
| Compression ratio | 8.5 |
| Power | 200 hp at 3100 rpm |
| Valvetrain system | 2 overhead valves per cylinder, operated by pushrods and rocker arms |
| Fuel feeding system | with one single-barrel Marvel Schebler MA4-5 gasoline carburetor |
| Ignition system | with two spark plugs per cylinder fed by two magneto distributors Scintilla S6RN-23 |
| Cooling system | air-fed |
| Lubrication system | forced by a gear pump |
| Weight | 135 kg (dry) |
| Mass-to-power ratio | 0.76 kg/hp |
| Specific power | 36.4 hp/litre |
| Propeller speed ratio | 9:1 by means of an epicyclic gear train |
Application
Augusta Bell 47 helicopter, model G, E, HTL-3 (millitary) and H1
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