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 cause and potential solutions for engine gear rattles in the Goshawk II model.
| Identifier | WestWitteringFiles\I\September1922\ Scan73 | |
| Date | 9th September 1922 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to De. c. to BY.{R.W. Bailey - Chief Engineer} ORIGINAL Hsl/LG16.9.22. GOSHAWK II. ENGINE GEAR RATTLES. X.4222 X.4247 We have found that the cause of the dynamo rattles has been due to slack in the serrations of the friction plate in the spring drive. In the case of some of the production cars there has been a fair amount of slack in this friction plate which has caused very pronounced rattles. Our tests have proved that we cannot afford to have any slack at that point if we are to have silent running gears. The reason we have been able to overcome the rattles by applying very light braking load, is that by that means we provided the damping which was absent owing to the slackness. Our tests go to show that the rattle is caused by the spring drive driving springs oscillating. These oscillations are started by the uneven turning of the Camshaft. This is proved by the fact that we have no rattles if the load of the valve springs is removed - again, we have no rattles if the spring drive is made solid with no slack in the friction plates. We consider that with the spring drive arranged with no slack between the friction portion and the spring portion, the gears on the Goshawk should be just as silent as those on the 40/50 H.P. Until, however, we can get the Camshaft to turn evenly, it would appear that we cannot afford to run with slack gears. We consider that the wearing surface in the single friction plate should be increased on the present design on contd:- | ||