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).
Conclusions on balance weights, flywheel vibrations, and crankchamber deflections.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan447 | |
| Date | 28th September 1931 | |
| RG.{Mr Rowledge} BY.{R.W. Bailey - Chief Engineer}) FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} ) C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} ORIGINAL. re.BALANCE WEIGHTS, FLYWHEEL, CRANKCHAMBER DEFLECTIONS, & BEARINGS. We have now straightened this matter out somewhat with the following conclusions: (1) To save the crankchamber and main bearings we must adopt balance weights, even if they are as low as 50% of the horizontal out of balance masses. This has become imperative owing to the increased RPM. of our car engines. For the sake of these bearings and many other reasons it is advisable, if possible, for these balance weights to equal the whole of the crank web, half the pin, and half the big end, so as to reduce as nearly as possible the horizontal load on the main bearings, but in any case should this be impossible it is still worth while to fit balance weights down to even one third of the desired amount. The 'R' engines in the Schneider tests have proved this, and we are all agreed. I believe the necessary information for their adoption is in the hands of BY.{R.W. Bailey - Chief Engineer} (2) Regarding the flywheel vibrations it was thought that by stiffening the shaft and the flywheel we could have raised the period above the master period of the crankshaft, and so out of the running range of the engine. Experiments suggested that this was impossible and it was thought that as we increased the stiffness of the flywheel, disc, and its mounting, the resulting vibration became worse, and logically it appeared to me that if we worked in the other direction of making the diaphragm of the flywheel more flexible we might improve matters. This has been done, and indicates that this idea is correct. It is also supported by theoretical reasoning, and by comparison between the 20/25. and P. 2., as well as by the experiments mentioned above, and as this is a simple and the least costly way of reducing this defect we hope it will be confirmed by further trial. It will be noticed that if it proves a success it will avoid the necessity of thinking about a tail bearing, or of having balance weights of the maximum mass, in fact, it looks as though the combination of small balance weights and the flexible disc in the flywheel will form an excellent move applicable to existing cars. In conclusion although HS.{Lord Ernest Hives - Chair}, BY.{R.W. Bailey - Chief Engineer}, and GRY.{Shadwell Grylls}, are satisfied with our own 8/6. weight scheme I prefer and hope we shall be able to adopt the 12/6 scheme brought forward by TSN. R.{Sir Henry Royce} [Handwritten Annotations in top right corner]: x 634. x 7010. x 5010. x 7000 x 5000 [Circular Stamp at the bottom]: RECEIVED HS{Lord Ernest Hives - Chair} SEP 30 | ||