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).
Engine bearing materials, crankcases, and design considerations discussed with A.E.C.
| Identifier | ExFiles\Box 116\1\ scan0094 | |
| Date | 13th January 1938 | |
| -2- Rm{William Robotham - Chief Engineer}/Mths.{Reg Matthews}8/MH.{M. Huckerby}13.1.38. The main bearings are not grooved completely, but there are two feed holes in each journal and two holes in the crankpin spaced similarly to the latest Bentley practice. They normally use Aluminium for crankcase but for this job they intend using a cast iron crankcase. We have agreed to let them have bearings for trial since their rubbing speed is rather low being only 65% of that of the Bentley. Further Details discussed. A.E.C. are diamond boring their main bearings and are to diamond bore the bearings we supply them with. Their normal bearings have exceedingly thick shells approximately .375 thick, the reason for this is, so they say, that the bearings, particularly white metal give better results than on thin shells. They used to use quite a normal thickness of steel backing at one time until one of their customers specified thick shells for the bearings, saying that they would give better results, from the experience of engines in this customer's hands they were compelled to agree that thick shells were certainly better than thin ones. A.E.C. have their own plant for producing Lead-Bronze bearings and both main and big end bearings are produced by the centrifugal method. They have also tried "Satco" and have had varying results, in some cases the bearings have failed through poor adhesion and others have just cracked up due to load. They have also tried most of the brands of white-metal and Cadmium silver bearings, all of which have so far failed. A.E.C. wanted to try our bearings placed alternately along the engine with Lead-Bronze, but we did not agree to this as we thought it would not be fair to our bearing material since we should be running with much less clearance than Lead-Bronze, and therefore, there would be a tendency with a stiff crankcase and crankshaft for our bearings to take most of the load. When we suggested this reason, A.E.C's thought that there would be enough deflection in the shaft to give all bearings an equal chance, we did not agree, and particularly so, since they informed us that for the engine in question they were to use a cast iron crankcase instead of the normal Aluminium. contd. | ||