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).
Test report on engine roughness and vibration, focusing on the crankshaft and flywheel performance at various speeds.
| Identifier | ExFiles\Box 137\4\ scan0044 | |
| Date | 1st November 1929 | |
| -2- 45 m.p.h. in 2nd. gear, approximately an 80% cure. The former booming periods at 26 and 31 m.p.h. had gone. (3) Crankshaft fitted - Flywheel as before. The engine now begins to get rough over 30 m.p.h. and appears to reach its max. roughness at 40 m.p.h. (3000 R.P.M.) afterwards becoming no rougher, from inside the car. This Vibration is by no means serious, and would be passed as very mild in a complete car at that speed. However, we think that - (1) If due to crankshaft vibration, then it will be much worse with pistons and rods. (2) As far as we know it should not be there at all. Vibration could be felt most at the centre of the crankcase along the lower horizontal web, where it was very severe. It appeared to be movement in a vertical plane. At the front feet the vibration was not as great as at the centre of the crankcase, and at the rear feet there was none at all, due we think, to the steadying effect of the flywheel. The vibration did not occur in periods, but merely got progressively worse with speed. There was no vibration of the gear box. The two cylinder blocks were fitted, held down with distance pieces under the nuts on the long studs; the head was not fitted. We could see movement of the blocks on the crankcase at the centre; this was shown by | ||