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).
Modifications made to an EAC carburetter for slow running.
| Identifier | WestWitteringFiles\M\2Jan1925-March1925\ Scan27 | |
| Date | 15th January 1925 | |
| R.R. 493A (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -6- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/ACL/1/M15.1.25. it would be necessary to modify the diaphragm ports and increase the size of the low speed throat in the correct ratio and then rely upon some other means such as bye-pass operated by the throttle as employed in the Zenith carburetter, to supply our slow running or correct metering at the lower depressions. Experiments with an EAC. carb. converted to work at the same depressions as the standard 40/50 HP. carburetter. The details of the alterations to the EAC. carburetter are as follows :- High speed throat .900 diam. The diaphragm ports in the high speed throat were made the same as the 40/50 HP. The extra air ports in the air valve cylinder were made the same as in the standard 40/50 HP. air valve cylinder except that they were made longer so that the air valve would not be at its maximum lift before the maximum speed (i.e. 2500 r.p.m.) of the engine. A spring giving a rating of 82 ozs/inch. was fitted. The low speed throat was .600 diam. The spring was proportioned to be equivalent to that of the standard 40/50 HP. carburetter taking account of the larger area of the air valve of the EAC. carburetter. Curves No.4. - are supplied showing that the depress-ions in the mixing chamber of the above carburetter and the standard 40/50 HP. carburetter are approximately the same. A print of the alterations is attached. The above carburetter simply amounts to a contd :- | ||