title: Franklin O-150
text: # Franklin O-150
  
  The Franklin O-150 (company designation 4AC-150) was an American air-cooled aircraft engine of the late 1930s. The engine was of four-cylinder, horizontally-opposed layout and displaced 150 cu in (2 L). The power output was nominally 40 hp (30 kW).
  
  ## Applications
  
  * Aeronca 50 Chief
  * Bartlett Zephyr
  * Clutton-Tabenor FRED
  * Fetterman Chickadee
  * Payne MC-7 pusher
  * Piper J-3 Cub
  * Rose Parakeet
  * Taylorcraft BF-65
  * Taylorcraft L-2
  
  ## Engines on display
  
  * Aerospace Museum of California - Franklin 0-150 (4AC-150)
  
  ## Specifications (4AC-150)
  
  Data from Jane's all the World's Aircraft 1938.
  
  ### General characteristics
  
  * Type: 4-cylinder air-cooled horizontally opposed aircraft piston engine
  * Bore: 3.625 in (92.1 mm)
  * Stroke: 3.625 in (92.1 mm)
  * Displacement: 149.6 cu in (2.45 L)
  * Length: 27.5 in (70 cm)
  * Width: 34.375 in (87.3 cm)
  * Height: 18.375 in (46.7 cm)
  * Dry weight: 155 lb (70 kg)
  
  ### Components
  
  * Valvetrain: Pushrod and rocker operated overhead valves. One intake, one exhaust
  * Fuel system: Stromberg NA-S2 updraught carburetor
  * Fuel type: 70 Octane gasoline
  * Oil system: Wet sump full pressure system
  * Cooling system: Air-cooled
  
  ### Performance
  
  * Power output: 40 hp (30 kW) at 1,875 rpm
  * Compression ratio: 6.66:1
  * Fuel consumption: 4.4 gal/h (17 L/h)
  * Specific fuel consumption: 0.54 lb/hp/h
  