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).
The investigation of engine rattles caused by the spring drive mechanism.
| Identifier | ExFiles\Box 42\2\ Scan093 | |
| Date | 15th December 1922 | |
| Contd:- -2- Hs{Lord Ernest Hives - Chair}4/LB15.12.22. ********** slipping at high speeds. On the engine we were investigating, as soon as we removed the springs in the spring drive and had the friction only, the rattles entirely disappeared. We arranged suffici-ent friction so that from measurement we could not notice any movement had taken place. As soon as we replaced the springs in the spring drive and still retained the same amount of friction, the gears rattled badly. We also found during this test that the worst rattle occurred when the spring drive was in exact neutral position. If we held the crankshaft and then twisted the camshaft so that the spring drive would take up a certain position and remain there owing to friction, the rattles would disappear. We found the cause of these rattles was slight slack between the friction device and the spring drive but it was a very small amount and considering that these serrations must be free enough to slide, we think they were as good as we could expect for an average job. We also tried having the springs only on one side of the spring drive. We found if we had the solid drive forward with the spring on the back, there were no rattles but if we had the spring drive forward, there were rattles. The results of our tests show clearly that the spring drive, unless made correctly, will produce and multiply rattles and make the engine far worse in this respect than if it had a solid pinion. We recommend that an alternative design for the spring drive should be got out for the 20 HP. and that it has cont | ||