Hirth HM 515

{{Infobox Aircraft Begin

|name = Hirth HM 515

|image =

|caption =

}}{{Infobox Aircraft Engine

|type=Inline piston engine

|manufacturer= Hirth-Motoren GmbH, Stuttgart-Zuffenhausen

|national origin= Germany

|first run=

|major applications=Siebel Si 202C Hummel

|number built =

|program cost =

|unit cost =

|developed from = Hirth HM 500

|developed into =

|variants with their own articles =

}}

The Hirth HM 515 was a four-cylinder air-cooled inverted inline engine, intended to power light aircraft of the 1940s. Due to World War II, demand for the light aircraft to be powered by the HM 515 dried up and only the Siebel Si 202C Hummel was powered by development engines before further work was abandoned.

The HM 515 closely followed the Hirth formula of Elektron (magnesium alloy) castings for the crank case and covers, with roller bearings and metered oil feeds for light weight, smooth running and low oil consumption. Only a small number were produced before the war precluded further production of the light aircraft class that the engine was intended to power. Flight testing was carried out in the Si 202Cs driving a {{cvt|1.8|m|0}} propeller, but no production ensued.{{cite web |title=Siebel Si 202 Hummel |url=http://www.histaviation.com/Siebel_Si_202_Hummel.html |website=www.histaviation.com |accessdate=4 February 2020 |archive-date=17 May 2017 |archive-url=https://web.archive.org/web/20170517184553/http://www.histaviation.com/Siebel_Si_202_Hummel.html |url-status=dead }}

Specifications (HM 515)

{{pistonspecs

|ref=Flugzeug-Typenbuch. Handbuch der deutschen Luftfahrt- und Zubehör-Industrie 1944{{cite book |last=Schneider |first=Helmut (Dipl.Ing.) |title=Flugzeug-Typenbuch. Handbuch der deutschen Luftfahrt- und Zubehör-Industrie 1944 |date=1944 |publisher=Herm. Beyer Verlag |location=Leipzig |isbn=381120484X |edition=Facsimile reprint 1986 |language=German |page=396}}

|type=4-cylinder air-cooled inverted in-line piston engine

|bore={{cvt|95|mm|2}}

|stroke={{cvt|105|mm|2}}

|displacement={{cvt|2.980|L|cuin|2}}

|length={{cvt|976|mm|1}}

|diameter=

|width= {{cvt|334|mm|1}}

|height={{cvt|570|mm|1}}

|weight={{cvt|68|kg|0}} dry, unequipped

::::{{cvt|74|kg|0}} wet, equipped

|valvetrain=1 inlet and 1 exhaust under-valve per cylinder driven by pushrods and rockers

|supercharger=

|turbocharger=

|fuelsystem=1x Pallas MF 35 carburetor

|fueltype=80 Octane

|oilsystem=dry sump, pressure feed with scavenge

|coolingsystem=air-cooled

|power=

:*{{cvt|65|PS|hp kW|0}} at 2,100 rpm for take-off

:*{{cvt|60|PS|hp kW|0}} at 2,040 rpm (high power rating) at sea level

:*{{cvt|55|PS|hp kW|0}} at 1,990 rpm (max. continuous) at sea level

|specpower={{cvt|21.8|PS/L|hp/cuin kW/L|2}}

|compression=6.2:1

|fuelcon=

|specfuelcon={{cvt|0.205|kg/PSh|lb/hph kg/kWh|3}} at max continuous

|oilcon={{cvt|0.001|-|0.003|kg/PSh|lb/hph kg/kWh|3}} at max continuous

|power/weight={{cvt|0.96|PS/kg|hp/lb kW/kg}}

B.M.E.P.: {{cvt|9.30|atm|bar psi}}

}}

Hirth HM 515

Specifications (HM 515)

References

Further reading