Rolls-Royce Archives
         « Prev  Box Series  Next »        

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).
Comparing the performance and practicality of various carburettor configurations for Continental Phantom & 25HP models.

Identifier  ExFiles\Box 13\3\  03-page396
Date  3rd March 1932
  
SG.{Arthur F. Sidgreaves - MD} FROM E.{Mr Elliott - Chief Engineer}
x7080.
C. to WOR.{Arthur Wormald - General Works Manager} Hs.{Lord Ernest Hives - Chair}
E1/MS.3.3.32. X.7080
K.5080
CARBURETTERS - CONTINENTAL PHANTOM & 25HP.

The best all round performance has been obtained with two SU carburetters, but there are serious objections, both technical and otherwise, to their use.

The two fixed choke RR carburetters mentioned in E1/M2323, as also the twin choke P. 2. carburetter, give a good boost at 1500., but are not so good at maximum speed. The value of this boost however is considerably discounted in making the carburetters reasonably silent in operation.

A single larger SU. carburetter gives a very good performance, in fact the power at maximum speed is practically as good as the two SUs., but somewhat discounted by rather more induction noise.

We see no reason why the new RR. expander should not do at least as well as the single SU. as regards performance, if made to the requisite dimensions, and as regards general handling and other features it should be much superior.

This latest carburetter has been made of the updraught form, and we know of no advantage to be gained by adopting the down draught pattern.

The natural question arising out of the foregoing is why not use two RR. expanding carburetters.

This would however be prohibitive as regards cost and complication for the comparatively small advance in performance gained.

It is true that the governor control mechanism could be deleted, but there would still be the features for throttle edge carburation, jet control for low and high speed, starter enrighment, and exhaust heat to be duplicated and connected up to the controls.

Also from the point of view of simplicity of appearance and adjustment, and of reliability, the single carburetter is much to be preferred.

E.{Mr Elliott - Chief Engineer}
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙