The Conrad C.III was a six-cylinder,

water-cooled Cooling tower and water discharge of a nuclear power plant Water cooling is a method of heat removal from components and industrial equipment. Evaporative cooling using water is often more efficient than air cooling. Water is inexpensive and no ...

inline aircraft engine designed by Robert Conrad. It was used on some German training aircraft during

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

. The engine was mainly produced under license by the German

Nationale Automobil Gesellschaft Nationale is a World Cup downhill ski course in Crans-Montana, Switzerland, opened in 1940. Crans-Montana hosted the World Championships in 1987, and Swiss racers (Pirmin Zurbriggen, Maria Walliser, Erika Hess, and Peter Müller) dominated in f ...

Development

After having designed two aircraft engines for the German

Kaiserpreis The Kaiserpreis () auto race, named after Emperor Wilhelm II, was held in 1907. Like his brother's Prinz-Heinrich-Fahrt held from 1908 to 1911, it was a precursor to the German Grand Prix. As Camille Jenatzy had won the Gordon Bennett Cup in auto ...

aircraft engine competition of 1912/13, Robert Conrad prepared an six-cylinder aircraft engine for the second ''Kaiserpreis'' competition anticipated to take place in 1914–1915. Further improvements on the engine design were done in 1915 by Robert Conrad while he was working for the

Deutsche Motorenbau-Gesellschaft Deutsch ( , ) or Deutsche ( , ) may refer to: * or : the German language or in particular Standard German, spoken in central European countries and other places *Old High German language refers to Deutsch as a way to define the primary characteris ...

. His work resulted in a six-cylinder water-cooled engine with increased bore which was capable of delivering at 1400 rpm. After a successful type test in February 1916 the engine was assigned the designation C.III (C for Conrad) by the German military.Kyrill von Gersdorff, Kurt Grasmann. ''Flugmotoren und Strahltriebwerke'', Bernard & Graefe Verlag, 1981, Due to insufficient production capacity at the Deutsche Motorenbau-Gesellschaft, the engine was produced by the Nationale Automobil-Gesellschaft (NAG). After NAG subsequently adapted the engine, it was uprated to and successfully type tested in November 1916. The new 210 hp variant however turned out to be unreliable and so subsequent versions of the engine were again rated , although with various design improvements over the original C.III.

Variants

Engine production was undertaken by NAG under license. Despite various adaptions of the original design all variants had the same bore and stroke. ;C.III: initial design by Deutsche Motorenbau-Gesellschaft (Conrad), license produced by NAG as ''C.III Nag''.Jack Herris. ''Development of German Warplanes in WWI'', Aeronaut Books, 2012, ;C.III Nag: initial production variant of the ''C.III'' engine, license production by NAG, , wet-sump lubrication system.''Der NAG-Flugmotor 185 PS - C III NAG''
Aircraft engine manual, 1917. ;C.III Nag a: improved production variant, , improvements over the preceding ''C.III Nag'' include revised T-shaped intake manifolds and a dry-sump lubrication system with revised oil sump and oil pump.''185 PS NAG Flugmotor Typ C III Nag a'', Aircraft engine manual, 1918. ;C.III Nag b: improved production variant, , improvements over the preceding ''C.III Nag a'' include an oil pump fed valvetrain lubrication system, a revised air pump for pressurizing the fuel system and a revised central placement of the two carburettors, along with provisions for mounting a wireless generator on the admission side of the engine.''185 PS NAG Flugmotor Typ C III Nag b''
Aircraft engine manual, 1918. ;C.IIIa: adapted and uprated variant of the initial ''C.III'' design, , only small number of engines produced, turned out to be unreliable. ;C.IIIb Nag: , no further details given. ;C.IIIav Nag: , new design, no further details given.

Applications

The Conrad C.III (Nag) engine was primarily allocated for training machines because it was found to be too heavy for use in fighter aircraft.P M Grosz. ''Windsock Datafile No.79, RUMPLER C.I'', Albatros Productions, Ltd., 2000, * DFW C.Vc (training aircraft)P M Grosz. ''Windsock Datafile No.53, DFW C.V'', Albatros Productions, Ltd., 1995, * Rumpler C.Ic (Germ) (training aircraft, built by Germania Flugzeug-Werke) * Gotha G.IV (SSW) (training aircraft, built by Siemens-Schuckertwerke)Peter M Grosz. ''Gotha!'', Albatros Productions Ltd., 1994, * LVG D.III (one prototype aircraft built)

Preserved engines

* A preserve
''NAG C.III engine''
is on public display at the

Polish Aviation Museum The Polish Aviation Museum () is a large museum of historic aircraft and aircraft engines in Kraków, Poland. It is located at the site of the no-longer functional Kraków-Rakowice-Czyżyny Airport. This airfield, established by Austr ...

in Kraków *
''NAG C.III, serial number 13217''
is part of the

Museum of Applied Arts & Sciences The Powerhouse Museum, formerly known as the Museum of Applied Arts & Sciences (MAAS), is a collection of 4 museums in Sydney, owned by the Government of New South Wales. Powerhouse is a contemporary museum of applied arts and sciences, explorin ...

Barraclough Collection in Sydney * A preserve
''NAG C.III engine''
is part o

at the

Politecnico di Torino The Polytechnic University of Turin (, abbreviated as PoliTO) is the oldest Italian public technical university. The university offers several courses in the fields of Engineering, Architecture, Urban Planning and Industrial Design, and is consi ...

Specifications (C.III NAG)

References