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 . The engine was named after the Battle of Crécy .
history
The development of the cylinders began in 1937 under project manager Harry Wood, with the cylinders himself being designed by Sir Harry Ricardo . The first complete engine was built in 1941 and had an output of 1400 hp . However, there were problems with the cooling due to strong vibrations . The ignition angle was 30 degrees and the typical boost pressure was around 1 kg / cm², bore × stroke 129.54 mm × 165.1 mm, the compression ratio was 7: 1 and the weight was 820 kg. The engine's exhaust gases exerted a thrust that was considered equivalent to an additional 30 percent propulsion power. It was therefore considerably louder than usual aggregates.
In contrast to other 2-stroke engines, a compressor was used to force the rich mixture into the cylinders, where it was ignited by two spark plugs in stratified charge in a spherical extension of the combustion chamber . Air-fuel mixture ratios from 15 to 20 were available to control 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 has been set up to run on diesel fuel .
Compressor throttling was also used to allow idling. The angle of the rotor blades of the impeller could be adjusted from 30 to 60 degrees. This made it possible to reduce fuel consumption, as less power was required to drive the compressor.
Sir Henry Tizard , Chairman of the Aeronautical Research Council, was a proponent of the engine. The performance of the machine itself was interesting, but the exhaust gas recoil at high speeds and altitudes made the Rolls-Royce Crecy a hybrid between conventional aircraft engines and the jet engines .
By the end of research in December 1945, only six Rolls-Royce Crecy had been built. The serial numbers were even because Rolls-Royce always assigned even numbers to the machines that turned clockwise . Crecy number 10 reached 2500 hp on December 21, 1944. Subsequent tests on individual cylinders achieved outputs equivalent to 5000 hp for the entire engine.