From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Page detailing engine development, covering issues with detonation, airflow tests, mixture distribution, and gas analysis results.
| Identifier | ExFiles\Box 148\2\ scan0101 | |
| Date | 28th November 1938 | |
| -8- Rm{William Robotham - Chief Engineer}/FWK.8/JH.28.11.38. had a larger magnitude than the rise in pressure caused by the exhaust ports opening. The difficulty was eventually overcome by modification to the exhaust manifold. Inaudible detonation could be seen on the indicator cards and this enabled the very limit of power to be obtained from the engine consistent with a low specific fuel consumption figure. The engine was developed almost entirely by the use of the indicator together with airflow tests through the manifolds and cylinder head. In conducting the airflow tests the parts to be studied were covered with a layer of grease and aluminium dust was then blown through the particular passage. In this way a well defined formation was produced on the surface. It is significant to note that of all the intake parts only about 70% of them were really doing any good and after the back four ports had been blanked off there was actually a slight improvement in performance all round. Great importance was attached to correct distribution of mixture to each of the four combustion chambers. The apparatus used for this test consisted of thermo couples inserted into the central electrodes of the sparking plugs. The temperatures thus measured gave an indication as to whether any particular cylinder had an over-lean or over strong mixture. Gas analysis tests were taken by the Orsatt method. The accuracy of this method was found to be within 2%. Throughout the running of the engine, there was a maximum of oxygen in the exhaust amounting to about 10%. Thus only 50% of the oxygen available was being consumed. It was hoped that the figure would be reduced by a further 50% in the near future with a consequent improvement in fuel economy and power output. | ||