Hirth HM 506

1930s German aircraft engine

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.

Applications

Bücker Bü 133 A
Fieseler Fi 99
Fieseler Fi 157 (UAV prototype)
Fieseler Fi 158 (UAV prototype)
Gotha Go 241
Klemm Kl 35 B (D-ERLQ)

Specifications (HM 506A)

Data from Jane's All the World's Aircraft 1938,^[2] Flugzeug-Typenbuch. Handbuch der deutschen Luftfahrt- und Zubehör-Industrie 1944^[3]

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 (364.68 cu in)
Length: 1,276 mm (50.2 in)
Width: 490 mm (19.3 in)
Height: 735 mm (28.9 in)
Dry weight: 149 kg (328 lb) dry, unequipped

174 kg (384 lb) wet, equipped

Components

Valvetrain: 1 inlet and 1 exhaust valve per cylinder, operated by push-rods and rockers
Fuel system: 2x SUM 713/1 down draught carburetters, automatic mixture control and suitable for inverted flight.
Fuel type: 80 Octane
Oil system: Fresh oil, metered for each cylinder. Rockers in oil bath.
Cooling system: air

Performance

Power output:

160 PS (158 hp; 118 kW) at 2,500 rpm (5 minutes) at sea level
145 PS (143 hp; 107 kW) at 2,420 rpm (30 minutes) at sea level
130 PS (128 hp; 96 kW) at 2,330 rpm (max. continuous / cruise) at sea level

Specific power: 26.8 PS/L (0.43 hp/cu in; 19.71 kW/L)
Compression ratio: 6.2:1
Specific fuel consumption: 0.220 kg/PSh (0.492 lb/(hp⋅h); 0.299 kg/kWh) at max continuous
Oil consumption: 0.003 kg/PSh (0.007 lb/(hp⋅h); 0.004 kg/kWh) at max continuous
Power-to-weight ratio: 1.075 PS/kg (0.481 hp/lb; 0.791 kW/kg)
B.M.E.P.: 9.65 atm (9.78 bar; 141.8 psi)

References

^ Gunston, Bill (1989). World Encyclopaedia of Aero Engines (2nd ed.). Cambridge, England: Patrick Stephens Limited. p. 77. ISBN 978-1-85260-163-8.
^ Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. pp. 60d–61d. ISBN 0-7153-5734-4.
^ Schneider, Helmut (Dipl.Ing.) (1944). Flugzeug-Typenbuch. Handbuch der deutschen Luftfahrt- und Zubehör-Industrie 1944 (in German) (Facsimile reprint 1986 ed.). Leipzig: Herm. Beyer Verlag. p. 396. ISBN 381120484X.