Hirth HM 508

The Hirth HM 508 was an air-cooled, eight-cylinder, 60° cylinder bank angle inverted-V aircraft engine built in Germany in the 1930s.^[1] It had a bore and stroke of 105 mm × 115 mm (4.1 in × 4.5 in) and developed 210 kW (280 hp) at 3,000 rpm.

HM 508
Type	Inline inverted 'V' piston engine
Manufacturer	Hirth
Major applications	Messerschmitt Bf 108

Variants

HM 8U

HM 508A

HM 508B

HM 508C

270 PS (266 hp; 199 kW)^[2]

HM 508D

280 PS (276 hp; 206 kW) at 3000 rpm^[3]

HM 508E

150 kW (200 hp)

HM 508F

HM 508G

HM 508H

180 kW (240 hp), low fuel consumption variant, with centrifugal supercharger geared at 3.86:1 crankshaft speed for long-range record breaking aircraft.

Applications

• Ambrosini S.7
• Gotha Go 146
• Gotha Go 149
• Heinkel He 116
• IMAM Ro.63
• Messerschmitt Bf 108
• Siebel Fh 104
• Weserflug We 271 Experimental aircraft

Specifications (HM 508D)

Data from Flugzeug-Typenbuch. Handbuch der deutschen Luftfahrt- und Zubehör-Industrie 1944,^[4] Jane's fighting aircraft of World War II,^[3] Jane's all the World's Aircraft 1938^[5]

General characteristics

• Type: 60° V-8, inverted air-cooled piston engine
• Bore: 105 mm (4.13 in)
• Stroke: 115 mm (4.53 in)
• Displacement: 7.96 L (486 cu in)
• Length: 1,292 mm (50.87 in)
• Width: 683 mm (26.89 in)
• Height: 815 mm (32.09 in)
• Dry weight: 222 kg (489 lb) dry, unequipped

241 kg (531 lb) wet, equipped

Components

• Valvetrain: 1 inlet and 1 exhaust under-valve per cylinder driven by pushrods and rockers
• Supercharger: Centrifugal supercharger geared at 4.47:1 crankshaft speed
• Fuel system: 2x Pallas-Zenith 65 VAH2 carbutettors
• Fuel type: 87 Octane gasoline
• Oil system: Pressure system for crankshaft, pistons and reduction gear at 1.5–2.5 atm (22.04–36.74 psi; 1.52–2.53 bar): splash lubrication for camshaft and supercharger
• Cooling system: Air-cooled
• 1x Double Bosch magneto

Performance

• Power output:
  

• 280 PS (276 hp; 206 kW) at 3,000 rpm (5 minutes) at sea level
• 258 PS (254 hp; 190 kW) at 2,920 rpm (30 minutes) at sea level
• 225 PS (222 hp; 165 kW) at 2,790 rpm (max. continuous) at sea level

• 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: 0.005 kg/PSh (0.011 lb/(hp⋅h); 0.007 kg/kWh) at max continuous
• Power-to-weight ratio: 1.266 PS/kg (0.566 hp/lb; 0.931 kW/kg)
• B.M.E.P.: 10.2 atm (10.3 bar; 150 psi)
• Reduction gear: Stoekicht sun and planet gears 0.666:1

See also

Comparable engines

• Argus As 10

Related lists

• List of aircraft engines

References

1. Gunston, Bill (1989). World encyclopaedia of aero engines (Fully rev. 2nd ed.). London: P. Stephens. p. 77. ISBN 1-85260-163-9.
2. 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. pp. 398–399. ISBN 381120484X.
3. Bridgman, Leonard, ed. (1989). Jane's fighting aircraft of World War II (1995 ed.). New York: Military Press. p. 294. ISBN 0517679647.
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. pp. 400–401. ISBN 381120484X.
5. Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's all the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. pp. 60d – 61d.