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).
The power output of an expanding carburetter tested on a Phantom II engine.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan118 | |
| Date | 5th November 1929 | |
| To R.{Sir Henry Royce} from HS{Lord Ernest Hives - Chair}/ACL. c. Sg.{Arthur F. Sidgreaves - MD} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} Ey. Hs{Lord Ernest Hives - Chair}/ACLA/AD5.11.29. X7080 R.R. EXPANDING CARBURETTER - POWER OUTPUT ON PHANTOM II ENGINE. Most of the work on the Expanding Choke Carburetter has been carried out on a Phantom I engine but we have now obtained a power curve of this carburetter on the Phantom II engine. The carburetter used for these tests had the following modifications :- 1. Choke increased to 1.525 dia. 2. Restrictor reduced to 1.300 dia. 3. Stromberg aero type slow running discharge nozzle near throttle edge. This took the place of the original brass discharge nozzle and could be rotated to expose the required amount of slot above the throttle edge to obtain the correct slow running mixture. The power curve compared with that of a standard Phantom II carb. is appended. The max. power obtained with the expanding choke carburetter was 148.5 B.H.P. at 2750 R.P.M. The standard carburetter gave a max. of 133.2 B.H.P. A gain of 15.3 B.H.P. or 11% is given by the expanding carburetter. A gain of 9% is given at 2000 R.P.M. The mixture was adjusted for each speed as we have not yet got the correct | ||