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).
Test No. 6 detailing modifications to induction pipes and carburetters, with results and conclusions.
| Identifier | ExFiles\Box 124\3\ scan0261 | |
| Date | 4th December 1934 | |
| -5- Test No. 6. Lec.4222 With reference to E/Ltd.3/HP.26.11.34. Induction pipe as Test No. 3. Special adaptors fitted between carburetters and induction pipe, these being arranged so that the slope suggested in Lec.4222 is obtained, the adaptors being water jacketed, and for this test the carburetters were also tilted themselves at an angle of 5o, to get as near as possible to the conditions in the above Lec. Adequate arrangement was also provided for draining any petrol which collected at the carburetter "bridge". Result. No further improvement over Test No. 3. The possible reason being that the heavy vapour issuing from the throttle edge is carried into the main pipe before use can be made of the 5o slope. Another point is, that the passage of air through the carburetter is sufficient to carry any petrol back into the main pipe which might be flowing down the slope. Conclusion. On such an engine as the SpectreCodename for Phantom III, where distance or capacity between the carburetters and the inlet ports is limited, camshaft overlap is the main controlling factor with regard to slow running. Also, if the wet mixture present in the induction pipe is allowed free access to the inlet ports, distribution is impaired. From the tests carried out it also appears that extra heat applied to the pipe is not sufficient in itself to control the wet vapour, as this wet mixture must be delayed in the pipe for the hot spot to do its work. In the design of induction pipe as on the Bentley, the wet mixture which falls to the bottom of the pipe is carried into the cylinders before sufficient effect has resulted from the hot spots. Hs{Lord Ernest Hives - Chair}/C.T.Salt. | ||