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).
Letter from Zenith Carburetter Co. regarding carburetter setup, fuel consumption, and economy jets for a 25 HP engine.
| Identifier | ExFiles\Box 122\1\ scan0199 | |
| Date | 12th June 1935 guessed | |
| THE ZENITH CARBURETTER CO. Limited. Sheet No............ 2. We understand that the pump fitted to the 25 HP engine delivers fuel at from 1.5 to 2 lbs. per square inch, and it would appear that a 2.5, or at most a 3m/m seating should be ample for your requirements. We are forwarding to you one of each of the above under separate cover. Mr. Ratcliffe, in his letter reports that the consumption is heavy, but we would point out that the carburetter as you have it at present is not fitted with an economy jet, which jet is very necessary if good consumption figures are to be aimed at. We are sending you, also under separate cover, a range of economy jets varying from 140 to 190, as it might be that you would like to test for yourselves the effect of these. It has been our experience that when using a downdraft carburetter some very efficient form of "hot spot" which is really hot is necessary, and in this connection it would seem that exhaust gas is the only medium capable of supplying the desired amount of heat. We take leave to offer a suggestion for the induction pipe, as shown on the accompanying hand sketch which we trust you will excuse. We think that best results might be obtained by mounting the carburetter as close to the induction | ||