Rolls-Royce Crecy

The Rolls -Royce Crecy was a liquid -cooled, 90 -degree V12, two-stroke aircraft engine with 26,1 liters capacity with a slider control, compressor and direct injection. The engine was named after the Battle of Crécy.

History

The development of the cylinders began in 1937 under the project manager Harry Wood, the cylinders were even designed by Sir Harry Ricardo. The first complete engine was built in 1941 and generated an output of 1400 hp. However, there were problems with the cooling due to strong vibrations. The firing angle was 30 degrees, and the typical boost pressure at about 1 kg / cm ² bore × 129.54 × 165.1 mm stroke, the compression ratio at 7:1, and the weight at 820 kg. The recoil of the exhaust is estimated to be about 30 percent of the total output of the engine. The engine was so much louder than usual aggregates.

Unlike other two - stroke engines, a compressor used to compress the mixture in the cylinders. Is used, a layer charge in a spherical enlargement of the combustion chamber in which two spark plugs the rich mixture ignited. Air-fuel mixture ratio of 15 to 20 were not available, in order to regulate the power between 60 and 100 percent. The lean mixtures reduced the peak pressure and thus allowed a higher compression or higher compressor pressure. At least one engine was set up for use with diesel fuel.

In addition, a compressor throttling is used to allow the idle speed. The angles of the blades of the impeller was adjusted from 30 to 60 degrees. This allowed the fuel consumption can be reduced as less power to drive the compressor was necessary.

Sir Henry Tizard, chairman of the Aeronautical Research Council was a proponent of the engine. The machine itself power was already interesting, but the exhaust recoil at high speeds and altitudes made ​​the Rolls- Royce Crecy to a hybrid between conventional aircraft engines and jet engines.

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