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The Lorraine 12Rcr Radium was an inverted liquid-cooled 60º V-12 piston engine, designed specifically for use by French racing seaplanes competing in the Coupe d'Aviation Maritime Jacques Schneider (commonly known as the Schneider Trophy) air races in the early 1930s.

12Rcr Radium
Type	V-12 inverted water-cooled racing piston engine
National origin	France
Manufacturer	Lorraine-Dietrich
First run	March 1931
Number built	3 complete engines with other part-completed engines used as maock-ups

Design and development

From the first Schneider Trophy race in 1913, France had a deep desire to fulfil the requirements of Jacques Schneider by winning the competition three times consecutively. Despite this desire, success for French aircraft was not forthcoming. To help address shortcomings, the STIAé ( service technique et industriel de l'aéronautique) issued a specification to three companies for a racing float-plane to compete in the 1932 Schneider Trophy. Power for the three aircraft was to be supplied by an engine specifically designed for the task, the Lorraine 12Rcr Radium.

The 12 Rcr was an inverted V-12 liquid-cooled engine with supercharger and reduction gearbox. Designed to deliver 2,000–2,200 hp (1,500–1,600 kW) at 4,000 rpm, the 12 Rcr had a high specific power from a displacement of only 28.7 l (1,750 cu in) and weight of 510 kg (1,120 lb). Testing on the bench was also carried out with Rateau Turbo-chargers, but

Operational history

Six engines were ordered, but it is unclear how many were completed, as the examples supplied to Bernard and Nieuport-Delage were merely empty shells for use as mock-ups. Bench testing commenced in March 1931, two months after the intended delivery to the airframe manufacturers, progressing slowly, leading to the first delivery of a complete engine to Dewoitine in July 1931. The second engine was tested at the Lorraine plant up to 3,000 rpm, but this highlighted concerns over the airworthiness of the engine, which was rejected for flight use. Once Great Britain had permanently secured the Schneider Trophy, further development of the Schneider racers and their specialised engines was abandoned.

Applications

The 12Rcr was intended to power the following racing seaplanes:

Bernard H.V.220

Nieuport-Delage NiD.651

Dewoitine HD.412

Specifications (12Rcr)

Data from [1]

General characteristics

• Type: V-12 inverted liquid-cooled piston engine
• Bore: 145 mm (5.7 in)
• Stroke: 145 mm (5.7 in)
• Displacement: 28.7 l (1,750 cu in)
• Dry weight: 510 kg (1,120 lb) dry

Components

• Supercharger: Rateau mechanical two-stage supercharger with a hydromechanical drive running at 7:1 crankshaft speed.

Performance

• Power output: 1,500–1,600 kW (2,000–2,200 hp) at 4,000 rpm
• Specific power: 0.3487 kg/kW (0.5733 lb/hp)}

References

Further reading

• Novara, A.A. V.V (1985). L'aviation - Grande Encyclopédie Illustrée (in French). .De Agostini Institut Géographique. p. 133.
• Bodemer, Alfred; Laugier, Robert (1987). DOCAVIA 25 : les Moteurs à pistons aeronautiques français (1900/1960) Tome II (in French) (Version 1, éd. 1998 ed.). Editions Larivière.
• Liron, Jean (1990). Les avions Bernard: DOCAVIA 31 (in French). Éd. Larivière. ISBN 2-84890-065-2.
• Grey, C.G., ed. (1931). Jane's all the World's Aircraft 1931. London: Sampson Low, Marston & company, ltd. p. 40d.

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