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).
Instructions for modifications to the Twin Choke Carburetter designs LeC's 2960 and 2962.
| Identifier | ExFiles\Box 13\3\ 03-page357 | |
| Date | 30th October 1931 | |
| L. Swindall. Please note & return To. By/Ogh. c. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X7080 BY/SS{S. Smith}2/N.30.10.31. RECEIVED 31 OCT 1931 P.2. Twin Choke Carburetter - LeC's 2960 and 2962. Before completing our instructions for the latest design of Twin Choke Carburetter to the above LeC's, the Experimental Dept. wish to embody the following modifications which have been found necessary on the earlier designs. 1. Variable Valve Sleeve E.81748 - to be modified as shown on V.1059 and the base circle of the valve E.81749 should be reduced to give less initial lap over the holes; Experimental Dept. suggest an initial lap of a quarter the diameter of the holes. 2. Choke E.81598 - Increase the diameter to 1.300 as shown on V.1022. 3. Throttle Valve Locations - Limits should be made as close as possible for locating the throttles accurately and preventing leaks. Experimental Dept. have asked for the ends of the throttle spindle bushes to be machined flush with bore in position, and the throttles fitted with out flats. This method was tried on the early 20 HP. carburetter and discarded because of throttle end movement when in the open position. 4. Slow Running Scheme - The eccentric hole type of slow running as shown on LeC.2924-25HP. 'Single' carburetter should be adapted in place of that detailed from LeC.2905. The Experimental Dept. have fitted a temporary scheme as shown on V.1058, V.1077 and V.1101. This design work should be dealt with as soon as possible as it will affect the throttle body casting E.82568, issued to the Experimental Dept. today. Continued. | ||