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).
Crankshaft design, recommending experiments with heavier counter-balanced shafts and stiffer crankcases.
| Identifier | ExFiles\Box 14\2\ Scan069 | |
| Date | 8th November 1929 | |
| -18- Hs{Lord Ernest Hives - Chair}/Ten5/AD. 8.11.29. Contd. vibration had added enormously to the life of the bearings. In view of the fact that when reporting on the Chrysler car (already heavier than ours) we considered the crankshaft too light, it is of interest to note that they have increased the weight still further in their latest models. Although some of our crankshafts have recently been increased in size, these have only been by small percentages, and we recommend that for experimental purposes a really heavy counter-balanced shaft be tried. The attached sketch shows the lines on which we should like to experiment in the 20 HP. for example, which at present needs it more than the Phantom II. In this shaft, the webs are all cut from discs. The objects of the half size counter weights are: (a) to admit of grinding the pins, and (b) to reduce the weight in the shaft that is not also contributing to stiffness, both lateral and torsional. We are anxious to have the shaft as heavy as reasonably possible, but to keep the period high, the percentage weight not contributing to stiffness should be as low as possible. We also recommend that we try a crankcase as stiff as we can possibly make it, on the lines of the Buick Marquette, and that for experimental purposes we make this in cast iron. We have found out that by temporary alterations to core-boxes it would be quite possible to grow radial webs on the bearing webs, and to make the bearing webs and other webs as thick as we like. The only other experiments we have in hand are experiments on the S.S. flywheel and clutch, and some crankcase | ||