Franklin O-335
| O-335/6AC | |
|---|---|
| |
| Type | Flat-6 |
| National origin | United States |
| Manufacturer | Franklin Engine Company |
| Major applications | Bell 47 |
The Franklin O-335 (Company designations variations on 6A4) was a series of air-cooled aircraft engines of flat-six configuration.
Design and development
These engines were commonly vertically mounted and used to power many early helicopters in the United States. They were closely related to the 2A4 and 4A4 2- and 4-cylinder engines. In various subtypes, the 6A4 remained in continuous production from 1945 to the time Franklin's United States operations ceased in 1975, with versions continuing in Polish production into the 1990s.
In 1947 this engine was modified into a water-cooled version by the Tucker Car Corporation for use in the 1948 Tucker Sedan. Tucker liked the engine so much that he purchased the Aircooled Motors/Franklin Engine Company, and it remained under the ownership of the Tucker family until 1961.
Variants
- O-335-1
- Military designation of vertical installation model for helicopters
- O-335-3
- Similar to -1 but changes in starter installation
- 6A-335
- 180 hp (134.2 kW) at 2,800rpm
- 6AL-335
- 150 hp (111.9 kW) at 2,600 rpm
- 6A4-125
- 125 hp (93.2 kW) at 2,200rpm
- 6A4-130
- 130 hp (96.9 kW) at 2,200rpm
- 6A4-135
- 135 hp (100.7 kW) at 2,450rpm
- 6A4-140
- 140 hp (104.4 kW) at 2,375rpm
- 6A4-145
- 145 hp (108.1 kW) at 2,600rpm
- 6A4-150
- 150 hp (111.9 kW) at 2,600rpm
- 6A4-165
- 165 hp (123.0 kW) at 2,800rpm
- 6A4-200
- 200 hp (149.1 kW) at 3,100rpm
- 6AG-335
- 220 hp (164.1 kW) at 3,400rpm
- 6AG4-185
- 185 hp (138.0 kW) at 3,100rpm
- 6AGS-335
- 260 hp (193.9 kW) at 3,400rpm
- 6AS-335
- 240 hp (179.0 kW) at 3,200rpm
- 6V-335-B
- 210 hp (156.6 kW) at 3,100rpm
- 6V-335-A1A
- 200 hp (149.1 kW) at 3,100rpm
- 6V-335-A1B
- 200 hp (149.1 kW) at 3,100rpm
- 6V4-165
- 165 hp (123.0 kW)
- 6V4-178
- 178 hp (132.7 kW) at 3,000rpm
- 6V4-200
- 200 hp (149.1 kW) at 3,100rpm
- 6VS-335
- 225 hp (167.8 kW) at 3,200rpm
Applications
Specifications (6AL-335 / 6A4-150-B3)
Data from [1]
General characteristics
- Type: 6-cylinder air-cooled horizontally opposed direct drive supercharged aircraft piston engine
- Bore: 4.5 in (114.3 mm)
- Stroke: 3.5 in (88.9 mm)
- Displacement: 335 cu in (5.49 L)
- Length: 37.4 in (950.0 mm)
- Width: 30.8 in (782.3 mm)
- Height: 21.6 in (548.6 mm)
- Dry weight: 307 lb (139.3 kg)
Components
- Valvetrain: OHV, 1x inlet valve, 1x exhaust valve operated by pushrods
- Supercharger: mechanically driven supercharger
- Fuel system: 1x Marvel-Schebler MA-3SPA updraught carburettor
- Fuel type: 80 Octane gasoline
- Oil system: 80 S.U. secs (15.6 cSt) grade pressure fed at 40 psi (275,790 Pa), wet sump
- Cooling system: Air-cooled
- Delco-Remy direct cranking electric starter motor
Performance
- Power output:
- (Take-off): 150 hp (111.9 kW) at 2,600 rpm for take-off
- (Normal): 150 hp (111.9 kW) at 2,600 rpm at sea level
- (Cruising): 112 hp (83.5 kW) at 2,350 rpm at sea level
- Specific power: 0.45 hp/(cu in) (20.35 kW/l)
- Compression ratio: 7:1
- Specific fuel consumption: 0.51 lb/(hp h) (0.311 kg/(kW h), 229.5 US gal/(hp h)) cruising
- Oil consumption: 0.01 lb/(hp h) (0.006 kg/(kW h), 4.5 US gal/(hp h)) cruising
- Power-to-weight ratio: 0.488 hp/lb (0.8 kW/kg)
- B.m.e.p.: 137 psi (945 kPa)
See also
Related development
- Franklin 2 series
- Franklin 4 series
- Franklin 6 series
- Franklin 8 series
- Franklin 12 series
- Franklin O-335
- Franklin O-805
Comparable engines
Related lists
Notes
- ^ Wilkinson, Paul H. (1945). Aircraft Engines of the world 1945. New York: Paul H. Wilkinson. pp. 80–81.
References
- Gunston, Bill. (1986) World Encyclopedia of Aero Engines. Patrick Stephens: Wellingborough. p. 57
- Erickson, Jack. Horizontally Opposed Piston Aero Engines
- Wilkinson, Paul H. (1945). Aircraft Engines of the world 1945. New York: Paul H. Wilkinson. pp. 80–81.
- US Department of Transportation Federal Aviation Administration Type Certificate Data Sheet E-238 Revision 12, December 8, 1994.