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).
The measurement of crankshaft deflections for Wraith and Bentley crankshafts.
| Identifier | ExFiles\Box 132\1\ scan0043 | |
| Date | 11th May 1938 | |
| 1116 By.{R.W. Bailey - Chief Engineer} from Rm.{William Robotham - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} c. Hs.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Mx.{John H Maddocks - Chief Proving Officer} c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} MEASUREMENT OF CRANKSHAFT DEFLECTIONS. The attached report indicates the measurements so far taken on Wraith & Bentley crankshafts. We are reassured to find that the Bentley crankshaft behaves in the same way as the Wraith crankshaft. We have been living with the present Bentley shaft for four years, and it has not caused any serious wear on timing gears, even on the six cars on which textolite was fitted. We are not, however, satisfied that such torsional vibrations should come within the running range of the engine, because they cannot be good for bearings or timing gears when a spring drive is dispensed with. Work we have already done indicates that we can improve matters, and we propose to obtain further information by running the Oldsmobile engine on the test bed. We are quite satisfied with B.III engine as at present running on the road, because the overdrive reduces the max. useful revs. on top to under 4,000 at which speeds, as will be seen from the diagrams, the torsional oscillations are not severe. Rm.{William Robotham - Chief Engineer} | ||