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).
Carburettor trials and future development plans for various designs, including up-draught and down-draught types.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan448 | |
| Date | 28th September 1931 | |
| HS.{Lord Ernest Hives - Chair} ) FROM R.{Sir Henry Royce} BY.{R.W. Bailey - Chief Engineer} ) C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} ORIGINAL CARBURATION. R4/M28.9.31. X7080 X5080 After considerable trials and experiments with double carburetters with fixed throats, it has been agreed that we should continue to compare the best of the single expanding carburetters and the double fixed throat carburetters because we are not yet satisfied that we can get our luxury carriage town running as reliably and economically with fixed throat carburetters as with the single expanding type. Other combinations have been ruled out, and as pointed out by R.{Sir Henry Royce} when they were suggested, the down draught design is considered to be not only dangerous through cylinder wear and seizing, but not to have any real advantage, and also the horizontal type (of which the S. U. is especially suitable) is not applicable to our designs, being less desirable from a petrol distribution point of view, and the risk of liquid petrol getting into the cylinders, so we are confining our attention to the up-draught carburetter which we have so long used in both car and aero work. Derby have in hand at present some improvements to the twin carburetter so as to overcome the heaviness of the floats which we have arranged to counter-balance by throwing out of the centre the shaft connecting the two floats. They have the separate carburetters for the Japan type of 25HP. and we hope to send them an up-draught single carburetter of the semi-expanding type like the down draught one, which they have. This we think may prove better than our present design because it is a straight through carburetter. It will have an emulsion main jet and throttle edge carburation, and will be expanding by virtue of extra air and an automatic decrease in the petrol restriction. To find out whether such a scheme is likely to prove successful we have suggested that a Claudel up-draught carburetter be tested on a P. 2. engine up to 1500 RPM., the throttle valve size of the carburetter being approximately 35 mm., which equals 1.4". R.{Sir Henry Royce} HS{Lord Ernest Hives - Chair} 30 SEP 1931 RECEIVED | ||