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).
Engine testing, discussing carburettor performance, induction systems, and oil consumption issues.
| Identifier | ExFiles\Box 36\2\ scan 187 | |
| Date | 10th October 1928 guessed | |
| .contd :- -3- make the best use of the mixture control. With four carburetters there is a greater tendency to obtain uncompensated and disturbing effects due to air intakes when in flight, than with fewer carburetters. This suggests that the blower type of induction - as mention by Mr. Royce - not necessarily supercharged, offers considerable possibilities in obtaining the economical conditions of working we have proved to be possible, and it is conceivable that the extra power observed by such a mixer would be appreciably outweighed by the improved distribution and the less tendency for it to be upset by external conditions. Throughout the throttled stages we worked with high water temperature, usually slightly over 90°C, and found this considerably improved the efficiency at the lower powers due to the lessened piston friction. The oil temperature was also kept reasonably high. A factor we did not anticipate encountering was oiling up of the plugs as we expected the very weak mixtures would result in hot plugs and therefore keep them free from oiling up. This however we found to be a very real danger on this type of test and was the only thing that caused us anxiety during the whole test after the stoppage due to this trouble. We however found we could deal with this trouble by opening up to about half throttle occasionally to heat up the electrodes and burn away the deposit. We admit this engine did not prove very good for oil consumption and in future for this type of work should reduce the oil consumption to the absolute minimum consistent with reliable lubrication. We are happy that it was this contd :- | ||