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).
Trade-off between engine performance versus smoothness and silence by lowering compression on S.S. cars.
| Identifier | ExFiles\Box 65a\3\ scan0087 | |
| Date | 23th July 1929 | |
| S/W. SECRET. x7770 Sg{Arthur F. Sidgreaves - MD}6/D23.7.29. To Hs.{Lord Ernest Hives - Chair} from Sg.{Arthur F. Sidgreaves - MD} c. to R.{Sir Henry Royce} c. to Wor.{Arthur Wormald - General Works Manager} c. to BY.{R.W. Bailey - Chief Engineer} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to C. c. to PN.{Mr Northey} Re: S.S. Cars. Referring to Hs{Lord Ernest Hives - Chair}5/MJ17.7.29, I am rather sorry to see that at this juncture there is a suggestion of lowering the compression with the consequent result of loss of performance, as whilst I appreciate that by so doing the engine is smoother and more silent, the question of loss of performance is of importance, but as smoothness and silence are also of very great importance to us it really becomes in both instances a question of degree. I presume you have made some definite tests indicating the difference in performance and I should be very glad to see these, and if possible, arrange a trial with you of a car the performance of which has not been lowered and one on which it has. The question is a very difficult one, because we really want to be no worse in smoothness and silence than the Phantom, but we also want, and were promised from the start, the improvement in performance, and whilst all the tests that I have made have indicated that we have not retained the smoothness and silence of the Phantom, they have, at the same time, indicated that the difference in performance between the two models is not as great as we had originally anticipated would be the case. We must bear in mind that from the very start the improvement in performance of the SS.{S. Smith} was one of the main reasons for its being put into production and on looking up some of the early memos. on the subject I see that this was made quite a feature of, but at the same time there was never the slightest suggestion that we should have to suffer in consequence of this increased performance in loss of smoothness and silence. I am pleased to note that there is no suggestion that the power compression should be made standard, and I sincerely hope that it will not be found necessary even to adopt this in cases where maximum performance is not required, because we have to bear in mind the fact that even if we deliver a car to someone whom we have reason to believe does not require maximum performance, it is quite possible that the car will be used, tried and judged on its merits by other people, or might even change hands at a fairly early stage in its history. Sg.{Arthur F. Sidgreaves - MD} | ||