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).
Improvements to the Continental Phantom engine's induction system to increase power, with a comparison to the Bentley engine.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan140 | |
| Date | 22th April 1931 | |
| X. FROM E.{Mr Elliott - Chief Engineer} C. to SG.{Arthur F. Sidgreaves - MD} WOR{Arthur Wormald - General Works Manager} C. to HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} ORIGINAL CONTINENTAL PHANTOM. It has always been said that the Phantom engine has consistently refused to develop more power at high speed whatever valve timing or induction system has been tried. We believe the valves are large enough to carry on the power curve for some distance yet, and that the desired result could probably be obtained by using two separate carburetters as close up to the two banks of three cylinders as possible. On the occasion of our last visit to Derby we took up with us a rough scheme of an induction system on these lines applied to the existing engine which we had made to find out how much length of induction pipe could be saved over the existing twin carburetter scheme. The carburetters were arranged between cyls. 1. and 2. on the front pipe, and 5. and 6. on the rear pipe, so that a supply of exhaust gas could be obtained from the cyl. head for hot jackets if desired. The resultant reduction of the average distance between carburetter and inlet valves was 6.5" or 36% on the existing twin pipe. With the pipes cast into the cyl. head, external cover plates and no exhaust heating, the reduction would be still greater. On the Bentley engine this latter scheme is used and owing to the fact that the cylinder head is not detachable the longitudinal induction passage can be close up to the valves which reduces the length of the pipe subjected to water heating, and minimises the risk of overheating the charge. The two Bentley carburetters are horizontal and arranged so as not to be directly opposite any one cylinder. What sort of distribution is obtained we do not know but the engines do not run particularly well idling, a phenomenon for which the S.U. carburetters are probably responsible. E.{Mr Elliott - Chief Engineer} | ||