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).
Continued report comparing oil suction systems on various chassis, discussing issues and proposing strainer design improvements.
| Identifier | ExFiles\Box 14\2\ Scan033 | |
| Date | 15th February 1929 guessed | |
| contd :- -2- an open bottom half test would confirm this. The Arrol Aster engine is fitted with leather flap valves over the wholes through the cross webs but we do not want to propose anything of this nature. ------------------------- The next question (which perhaps should have been the first) is why is this trouble not complained of on the Phantom and India Chassis. The base chambers of these chassis are no better but rather worse than SS.{S. Smith} for uncovering the oil suction ports under the conditions discussed. The 3 systems compared are as follows : SEE ORIGINAL FOR SKETCH. There is one important difference to be observed between SS.{S. Smith} and the other two chassis. On the SS.{S. Smith} the pump proceeds to evacuate all the air from the strainer before touching a drop of oil while on the others, and in particular the Phantom, the pump sucks at the oil as soon as any flows through the coarse gauze and goes on happily working with the upper part of the strainer full of air. No doubt as soon as the engine picks up in speed the air will be evacuated owing to the difference of pressure caused by the resistance of the gauze. The Phantom is particularly good in having the minimum of air capacity on the suction side of the pump. ------------------------- In designing the SS.{S. Smith} originally we endeavoured to arrange the strainer in the ideal way with the dirt on the outside and this led us into drawing off the oil from the top. We now have in hand a scheme for using a dip pipe with the present type of strainer and an alternative with the strainer inverted on the lines of the India chassis. We propose that one of them be adopted and at the same time some of the work undertaken on the sump is of value in keeping the oil in its proper place and perhaps should be adopted as well. e.{Mr Elliott - Chief Engineer} | ||