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 and chassis design, focusing on frame twist, vibration, mounting, and a review of competitor practices.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan129 | |
| Date | 18th April 1931 guessed | |
| (2) I have now no anxiety about the twist of the frame doing any harm to the crankchamber because it and the gearbox are enormously strong, and I should like to see front arms on the engine and arms on the rear end of the gearbox so that torsionally the chassis shall be superior to anything we, or even all others, have ever had. In passing I think we ought to re-examine the Hispano to find out what their long experience of an engine similar to ours has lead them to adopt. One would naturally continue to use rubber in the mounting and the sandwich feet we have on P. 2. seem as good as anything one can think of at the moment. I do not remember exactly why we thought the 8 cyl. Vee inferior to the 12 Vee except for torque vibrations. With 8 cyls. or more we get a smooth drive between the crankshaft and camshaft, and a starter motor drive which is smooth enough to drive steadily at slow speeds. We should get no rattles in servo drive and only need quite a light flywheel so that there should be no trouble with whirling flywheel, no over-running vibrations, and the crankshaft is not only short but there is little or nothing to put it in torsional vibration though we should leave room for a damper in case of harmonics from power impulses. There is also extremely little pumping of gas from one crank compartment to another. Now we come to the practice of the first class cars in other countries. America has the Packard 8., Lincoln 8., Cadillac 12. and 16., and even Chrysler 8. In Germany there are the Mercedes 8. and Maybach 12. and many other examples. Will Mr. Elliott try these ideas over in rough drawings and applied to our chassis so that we can get the matter put before the RR. directors at an early date. Except for some doubt about the damper and the flywheel whirl there seems little to be said against the whole of P. 2. power unit, and but for booms the results seem very good indeed, and I have seen enough to fear a return to a frame which has no help from the engine for torsional stiffness. Our old Silver Ghost and P. 1. practice will not again be considered passable. The trouble with bonnets wearing their strips and knocking cannot now be considered passable because we know the reason, and they are curable. 18-EX. is better than any previous type. The damper I suggest for present 6 cyl. engines is similar to an ordinary brake drum internal type, probably aluminium steel lined, and the brake is a split ring covered on the outside with fibre or other no-seizing-material sprung outwards by its own | ||