De Havilland Gipsy Major

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The de Havilland Gipsy Major or Gipsy IIIA was a 4-cylinder, air-cooled, inline engine used in a variety of light aircraft in the 1930s including the famous Tiger Moth biplane. The engine was a slightly modified Gipsy III which was effectively a de Havilland Gipsy engine modified to run inverted so that the cylinders pointed downwards below the crankcase. This allowed the propeller shaft to be kept in a high position without having the cylinders blocking the pilot's forward view over the nose of the aircraft. One disadvantage of the inverted configuration was the high oil consumption (up to 4 pints per hour) requiring regular refills of the external oil tank. The Major was a slightly bored out (118 mm from 114 mm) Gipsy III. First built in 1932, total production of all Gipsy Major versions was 14,615 units.

Examples are on display at the Mosquito Aircraft Museum.

[edit] Aircraft

• De Havilland Tiger Moth
• Miles Magister
• Miles Whitney Straight
• Saab 91 Safir
• Ikarus Aero 2
• RWD-5bis
• DHC-1 Chipmunk

[edit] Specifications (Gipsy Major)

General characteristics

• Type: 4-cylinder air-cooled inverted inline piston aircraft engine
• Bore: 4.646" (118 mm)
• Stroke: 5.512" (140 mm)
• Displacement: 373.7 in³ (6.124 L)
• Length: 48.3" (1227 mm)
• Width: 20.0" (508 mm)
• Height: 29.6" (752 mm)
• Dry weight: 300 lb (136 kg) Mk 1F to 322 lb (146 kg) Mk 1D

Components

• Valvetrain: OHV
• Fuel system: Downdraught Hobson A.I.48 H3M (Mk 1C and Mk 7) or H1M (others)
• Cooling system: Air-cooled

Performance

• Power output: 122 hp at 2,100 rpm - 145 hp (108 kW) at 2,550 rpm
• Specific power: 0.39 hp/in³ (17.6 kW/L)
• Compression ratio: 5.25:1 (Mk 1 and 1F) or 6.0:1 (others)
• Power-to-weight ratio: 0.48 hp/lb (0.78 kW/kg)

[edit] See also