title: De Havilland Gipsy Twelve
text: # De Havilland Gipsy Twelve
  
  The de Havilland Gipsy Twelve was a British aero engine developed by the de Havilland Engine Company in 1937. Approximately 95 were manufactured. It was known as the Gipsy King in Royal Air Force service.
  
  ## Applications
  
  * de Havilland DH.91 Albatross
  * de Havilland DH.93 Don
  
  ## Engines on display
  
  Preserved de Havilland Gipsy Twelve engines are on public display at the following museums:
  
  * de Havilland Aircraft Museum
  * London Science Museum.
  
  ## Specifications (Gipsy King I)
  
  Data from Lumsden
  
  ### General characteristics
  
  * Type: Inverted 60 degree V-12 piston engine
  * Bore: 4.646 in (118 mm)
  * Stroke: 5.512 in (140 mm)
  * Displacement: 1121.3 cu in (18.4 L)
  * Length: 82.6 in (2,098 mm)
  * Width: 31.5 in (800 mm)
  * Height: 37.4 in (950 mm)
  * Dry weight: 1,058 lb (480 kg)
  
  ### Components
  
  * Valvetrain: Overhead valve
  * Supercharger: Single speed
  * Fuel type: 87 Octane petrol
  * Cooling system: Air cooled
  * Reduction gear: Spur geared, reduction ratio 0.667:1
  
  ### Performance
  
  * Power output: 425 hp at 2,450 rpm at 0 psi boost (five minutes maximum)
  * Compression ratio: 6:1
  * Power-to-weight ratio: 0.4 hp/lb
  