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).
Carburetter issues for the 20/25 HP model, focusing on the float chamber and proposed modifications.
| Identifier | ExFiles\Box 102\1\ scan0234 | |
| Date | 27th December 1934 | |
| To E.{Mr Elliott - Chief Engineer} cc S.S.G.S. From HS{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation} NOR. BY.{R.W. Bailey - Chief Engineer} to NX. HS{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation}2/KW.27.12.34. 20/25 HP. Carburetter. With further reference to our report HS{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation}24/KW.8.10.34. In the above report we mentioned one of the serious troubles being experienced by production with the horizontal carburetter. This is due to a very large extent to the fact that the depression in the float chamber is unnecessarily high, owing to the interference from the throttle edge as explained in our previous report. The result of this factor in practice is that the carburetter is very sensitive to any leakage which may and does occur in the vicinity of the float chamber. A separate passage must be employed and incorporated in the air intake casting for the purpose of float chamber balance. Float Chamber Lid.{A. J. Lidsey} A better washer should be used beneath this lid{A. J. Lidsey}, such as the thicker kind of "vellumoid" which is available. Also this lid{A. J. Lidsey} should be held down by 3 screws instead of 2 as at present. There is normally a metal label, rivetted to this lid{A. J. Lidsey} mentioning R.R. and S.U. patents. The fixing is such that serious leakage takes place in many cases. We suggest that this label should be moved to a position similar to the 2nd. label (re adjustment of the carburetter etc.) Square Section and reversed Throttle Action. A carburetter has been made and thoroughly tested, incorporating the following modifications. Carb. body E.80068 modified to EX.15739, which reverts to square internal section, and incorporates a reversed throttle action. The merits of these two points will be considered separately. | ||