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).
Notes on road shocks, supercharging, and bearing materials.
| Identifier | ExFiles\Box 178\2\ img116 | |
| Date | 8th January 1936 | |
| -2- (9) Road Shocks. Cy. maintains that it is important to arrange correct steering geometry and as near as possible a wheel movement in which the camber does not change. Although a new tight steering box will for a time eliminate road shocks, the moment it becomes loose shocks will reappear if they are inherent in the front end. If we do not lose controllability by lowering the roll centre on the Ph.III, we recommend doing so as an improvement for road shocks. (10) Supercharging. Graham-Paige and Auburn are the only two Companies using superchargers. Graham-Paige apparently went to the supercharger because this method of obtaining more power was cheaper than enlarging the bore of the engine, but everyone agrees this latter method gives better fuel economy. There was a difference of opinion as to the best supercharger drive, but General Motors Research Laboratory prefer the Auburn epicyclic steel roller to the Graham type. Grahams, however, said that if any dirt get into the oil, rapid wear of the Auburn type would take place, and the parts would have to be renewed. A supercharger should be regarded as a means of getting more power from an engine in which the bore cannot be enlarged and a new engine is not available. (11) Bearing Materials. There were varying opinions as to the pros and cons of Cadmium bearings, but as Hopkins says the total output of Cadmium in the States is insufficient to provide bearings for the Ford cars alone, its use is not likely to continue. General Motors Research Laboratory have produced a lead bronze strip bearing which they say will run at white metal clearances. We have brought back sufficient bearings to try these out in one of our engines. They say that the reason why the normal lead bronze requires a large clearance is because of the crankcase and crankshaft deflections causing very high localised loads on the edges of the bearings. If, however, we shape the bearings like those in white metal that have run endurance, lead bronze will be able to run at a small clearance. In this connection we shall try the Packard arrangement of crankshaft balance weights which they say causes the | ||