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).
Issues with oil temperature on the Bentley and proposing design improvements.
| Identifier | ExFiles\Box 131\1\ scan0213 | |
| Date | 21th August 1936 | |
| To E.{Mr Elliott - Chief Engineer} from Rm.{William Robotham - Chief Engineer} X 11/4 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}9/KW.21.8.36. Oil Temperature on the Bentley. E.11/HP.20.8.36. We quite agree that the oil temperature on the Bentley is higher than we should like. The larger oil pump, however, should completely dispose of the poor oil pressure under idling conditions. Of course with Hall's metal bearings we have made this engine so that it does not mind hot oil and should hardly be justified in going to any great expense in cooling the oil therefore. We do feel, however, that the bottom half on the Bentley is now out of date and could with advantage be redesigned. In the first place we think it is an admission of failure to have to put an external oil filter such as the Tecalemit on the Bentley. We really did it in order to show that clean oil would overcome our bearing trouble, but we think basically one filter should do the job and that filter should be in the sump. We believe that one of the troubles is due to the fact that we draw the oil from the bottom of the crankcase and have no settling chamber. We think the filter should be of the double gauze type as used on the Phantom III. We have some experiments going forward on these lines. We think that an increased number of ribs would be justified. As we discovered on oil cooling tests on the Peregrine, it is essential to have as much rib area outside the crankcase as inside in order to get any benefit therefrom. We suggest that it is imperative that any new bottom half should start life in magnesium and continue in this material. The bottom half is really an ideal piece to make in magnesium. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||