Hirth HM 506

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HM 506
Type Inline piston engine
National origin Germany
Manufacturer Hirth Motoren GmbH
Major applications Bücker Bü 133

The Hirth HM 506 was a six-cylinder air-cooled inverted inline engine that was developed from the earlier four-cylinder HM 504.[1] The HM 506 was a popular engine for light aircraft of the 1930s to 1940s and powered the Bücker Bü 133A model trainer. The engine featured a cast magnesium alloy crankcase.


Specifications (HM 506)[edit]

Data from Grey 1972, p. 60d-61d

General characteristics

  • Type: 6-cylinder air-cooled inverted inline
  • Bore: 105 mm (4.13 in)
  • Stroke: 115 mm (4.53 in)
  • Displacement: 5.976 L (364.7 cu in)
  • Length: 1,276 mm (49.8 in)
  • Width: 490 mm (19.1 in)
  • Height: 735 mm (28.66 in)
  • Dry weight: 149 kg (328 lbs)


  • Valvetrain: 1 inlet and 1 exhaust valve per cylinder, operated by push-rods and rockers
  • Fuel system: 2 Sum down draught carburetters, automatic mixture control and suitable for inverted flight. Twin Bosch magnetos.
  • Oil system: Fresh oil, metered for each cylinder. Rockers in oil bath.
  • Cooling system: air




  1. ^ a b Gunston 1989, p.77.


  • Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. ISBN 0-7153-5734-4. 
  • Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9

External links[edit]