Hirth HM 515

from Wikipedia, the free encyclopedia

The Hirth HM 515 was a piston aircraft engine made by the German manufacturer Hirth and intended for general aviation .

development

The four-cylinder gasoline engine with OHV valve control presented in 1938 was only manufactured in small numbers from 1940 after a sample test had been carried out because, due to the war, there was no longer any need for such weakly powered aircraft. It could have been used in the so-called Volksflugzeugs such as Bücker Bü 180 , Fieseler Fi 253 Spatz , Haller Ha 22 and 23, Klemm Kl 105 , Pause Mücke, Siebel Si 202 or Gotha Go 150 .

The first engine was long-term tested in a Siebel Si 202 Hummel.

construction

The structural design of the motor reveals its derivation from the previous Hirth HM 500 . Like this one, it was an air-cooled engine with four hanging cylinders. The propeller was driven directly from the crankshaft without a gearbox. The equipment carrier was flanged to the rear end of the otherwise one-piece and completely closed crankcase. There was also the Pallas MF 35 cross-flow carburetor, which supplied the engine with a mixture and had a switchable preheating. The multi-split crankshaft , which was assembled in the crankcase, allowed the use of roller bearings instead of the otherwise common plain bearings, which also applied to the undivided connecting rods. Only the piston pins had sliding bearings. The pistons were each sealed by two compression rings and an oil control ring. The tightly ribbed cylinders made of special gray cast iron, together with the cylinder heads made of a light metal alloy, were each connected to the crankcase by four tie rods. The camshaft mounted in the housing operated the overhead valves via tappets, push rods and rocker arms , one each for inlet and outlet. Their resting places served simple coil springs as valve springs . 3.5 liters of lubricant were available for dry sump lubrication , which were circulated by a pressure pump and a return pump. The oil tank was part of the equipment rack. The HM 515 could be operated with a single or a double Bosch magneto ignition system, which only acted on one spark plug per cylinder. The ignition timing was adjusted by hand. The engine was started with the help of an insertable crank.

Technical specifications

  • Start Power: 65 hp (48 kW) at 2100 min -1
  • Travel Power: 55 hp (40.5 kW) at 1,990 min -1
  • Specific consumption: 205 g / PSh (278.5 g / kWh)
  • Displacement: 2.98 l
  • Stroke: 105 mm
  • Bore: 95 mm
  • Compression: 6.2: 1
  • Length: 976 mm
  • Width: 334 mm
  • Height: 570 mm
  • Installation weight: 74 kg
  • Firing order: 1 - 3 - 4 - 2

swell

  • Kyrill von Gersdorff, Helmut Schubert, Stefan Ebert: Aircraft engines and jet engines. Bernard & Graefe publishing house, ISBN 978-3-7637-6128-9 .
  • Helmut Schneider: Airplane type book. 5th edition, Herm. Beyer Verlag, Leipzig 1944.