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).
Crankshaft modifications for a supercharged Bentley engine, specifically the reduction of bearings.
| Identifier | ExFiles\Box 3\6\ 06-page202 | |
| Date | 16th June 1934 | |
| X453 To Sg.{Arthur F. Sidgreaves - MD} and WOF. from E.{Mr Elliott - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} E.3/HP.16.6.34. re Bentley. In connection with the scheme for adding the centrifugal supercharger to the Bentley engine, we are also proposing to alter the crankshaft from 7 to 4 bearings, as we feel that the increase of boost should raise the speed on which the power curve peaks and this will call for a higher major critical speed on the crankshaft if we are to take full advantage of this improvement. It has usually been held in the past that a supercharged engine should have a main bearing on both sides of each cylinder, but we find that the Graham Paige are only using a 5 bearing shaft on their 8 cylinder engine and also we feel that the additional roughness which we expect may be introduced by leaving out bearings can be dealt with by using a sufficiently flexible engine mounting, and that the passengers will be unaware of it as far as the chassis and body phenomena are concerned. E.{Mr Elliott - Chief Engineer} | ||