The Renault 12R was an

air-cooled Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. Air-cooled designs are far simpler than their liquid-cooled ...

inverted V12 aircraft engine developed by the

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engineering company

Renault Renault S.A., commonly referred to as Groupe Renault ( , , , also known as the Renault Group in English), is a French Multinational corporation, multinational Automotive industry, automobile manufacturer established in 1899. The company curr ...

in the 1930s. The design was based on mounting two 6Q six-cylinder engines on a single crankshaft. In production, the engine was rated between , although a high performance version built for the sole Caudron C.712 racing special produced . More than one third of production went to power the Caudron C.714 light fighter that fought in the early stages of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

for the

and

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Design and development

The 12R was developed by Renault in the 1930s. The design was derived from the successful Renault Bengali, using the same construction techniques and being of essentially steel construction. It was based on the 4.46, a test engine developed by mounting two 6Q six-cylinder engines on the same

crankshaft A crankshaft is a mechanical component used in a reciprocating engine, piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating Shaft (mechanical engineering), shaft containing one or more crankpins, ...

. The engine retained the bore and stroke of the smaller engine. The

cylinder A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite ...

s and

piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder (engine), cylinder a ...

s were made of forged steel and connected in pairs to an eight bearing crankshaft. The

crankcase A crankcase is the housing in a reciprocating engine, piston engine that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block. Two-stroke engines typically use a crankcase-compression design, res ...

was made of aluminium alloy coated with magnesium. A centrifugal

supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement (engine), displacement. It is a form of forced induction that is mechanically ...

was mounted to the rear. The engine was produced in both right handed and left handed versions, the difference being the direction of

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

rotation. Designed to be fitted to a range of aircraft, both civil and military, the engine was originally rated at when first introduced in 1935. However, the majority manufactured, 290 out of a total production of 325, were the 12Rc introduced in 1939. Of these, 120 powered the Caudron C.714 light fighter which served in

. In addition to examples of the aircraft ordered the

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, thirty-five were delivered to the

Polish Air Force The Polish Air Force () is the aerial warfare Military branch, branch of the Polish Armed Forces. Until July 2004 it was officially known as ''Wojska Lotnicze i Obrony Powietrznej'' (). In 2014 it consisted of roughly 26,000 military personnel an ...

in France and a further six to the

Finnish Air Force The Finnish Air Force (FAF or FiAF; ; ) is one of the branches of the Finnish Defence Forces. Its peacetime tasks are airspace surveillance, identification flights, and production of readiness formations for wartime conditions. The Finnish Air ...

, although the latter were not used in combat. The most powerful version was the 12R Spécial of 1937 which produced at 3250 rpm and powered the single C.712 racing aircraft derived from the fighter.

Variants

;Renault 12R: ;Renault 12Rb: ;Renault 12Rc: ;Renault 12Rm: ;Renault 12Ro: ;Renault 12R-00: LH rotation ;Renault 12R-01: RH rotation ;Renault 12R-02: ;Renault 12R-03: ;Renault 12R-09: ;Renault 12R Spécial:

Applications

* Caudron C-446 * Caudron C.560 * Caudron C.581 * Caudron C.710 * Caudron C.712 * Caudron C.714 * Caudron C.870 * Dewoitine D.720 * Dewoitine D.750 * Hanriot H.220 (prototype only) * Romano R.110

Specifications (12R-00)

References

Citations

Bibliography

* * * * * * * * * * {{Renault aeroengines 1930s aircraft piston engines Inverted V12 aircraft engines 12R Aircraft air-cooled V piston engines