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).
Conclusions from flexible engine mounting tests, discussing clutch performance and issues arising from increased smoothness.
| Identifier | ExFiles\Box 14\5\ Scan293 | |
| Date | 11th June 1934 | |
| X-7005 To Hs.{Lord Ernest Hives - Chair} from Hs{Lord Ernest Hives - Chair}/Ra, c. to Wor.{Arthur Wormald - General Works Manager} c. to S. c. to By.{R.W. Bailey - Chief Engineer} c. to Ds. c. to Hdy.{William Hardy} c. to LV. Hs{Lord Ernest Hives - Chair}/R.9/KM.11.6.34. FLEXIBLE ENGINE MOUNTING. We have now come to fixed conclusions on our flexible engine mounting tests. We find that with our existing clutch no matter what linkage we use between the pedal and the operating mechanism, jaggers will occur if the engine is allowed complete freedom of movement. The reason that the Terraplane clutch does not jagger under the same conditions is that it is a cork clutch running in oil, which gives an exceptionally smooth take-up. We are investigating this type of clutch, but it has never been regarded as being so durable as the single plate dry clutch. It is not fitted by any of the more reputable American manufacturers such as Chryslers and General Motors. Since Chryslers have an engine mounting which appears to be as flexible as the Terraplane, it would seem to be possible to make a single plate dry clutch which is much smoother in take-up than our own. This is the line upon which we are working. Any clutch modification however requires a lot of testing before it can be put into production. In the meantime, however, it is found that if the engine movement is partially restrained an intermediate degree of smoothness results and the clutch behaves satisfactorily. In the case of the 20/25 the engine movement is restricted by the two links in the front. On the 40/50 the front feet are more widely spaced which gives us the same results. It is in this condition that the two cars will run 10,000 miles. The increased smoothness of the rubber engine mounting is sufficient to show up (1) carburetter noise, (2) exhaust fish tail noise. Both these points are receiving attention and modifications are in hand which will be fitted to the 10,000 miles cars. Hs{Lord Ernest Hives - Chair}/KM. | ||