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).
Gear design, lubrication, gearbox construction, and propeller shaft couplings, including comparisons with Cadillac.
| Identifier | ExFiles\Box 124\3\ scan0352 | |
| Date | 9th April 1935 | |
| -2- HDY.{William Hardy}1/MN.9.4.35. a 22% increase in mean diameter of the teeth for the top gear. We should not have thought that a reduction in number would give any advantage. We have compared the slackness in the teeth of the Cadillac with our practice and cannot find that we are inferior. Our Prod. Dept. is well aware of the need for a close fit and have no difficulty, we are informed, in meeting test requirements. The Cadillac has one advantage in this matter of slack in the teeth in that the teeth on the sleeve are ground and so distortion troubles are eliminated on this piece. We do not know whether the grinding has been done for this purpose, it may have been found of some help to prevent the pieces working out of mesh which we know is one of their troubles. 4. Thick Gear Oil. The value of this can very easily be determined but in any case it is doubtful whether this is a way out owing to synchromeshing troubles with thicker oil. 5. Small Cast Iron Boxes More Compact, Less Liable to Amplify Noise. To what extent we should be better off in various directions regarding silence with a cast iron we never seem to be able to find out although we have had a cast iron box on test. The conclusion from our own experiments seems to me to be that cast iron did not make much difference. At all events the favourable difference, if any, did not justify the extra weight. Our Phantom and 20/25 boxes are larger than those for American cars of the same power but my impression is that our own experience does not indicate any marked superiority for the small box not even when the power passing through the small box is much less than through the large. 6. Propeller Shaft Coupling to Third Motion Shaft Keyed and on Taper. We do not understand how the impression has been obtained that this is American construction as the almost invariable practice is to carry the coupling Contd: | ||