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).
Comparing torsional vibration characteristics and dampers of various engine designs.
| Identifier | ExFiles\Box 173\1\ img302 | |
| Date | 31th January 1934 guessed | |
| IX VIII better power out of the 8 in line than the V8. I have the power curves. I went over the torsional vibration diagrams of their 12 & 16 with them, diagrams taken with the summers indicator (much like we used) no crank damper being fitted. The V8, which is 5-bearing, has the 8 per rev at 1600 R.P.M, the 12 which is 4 bearing and has a peculiar balance scheme which gives 85% balance of the centre fine but not equal reduction of load on all bearings, has the 12 per-rev at 2700. The amplitude in either case appears to be about the same and is taken care of with the rubbered centred damper. G.M. research say that if the amplitude of any torsional exceeds 1° they have difficulty in damping it out. (Cadillacs are not altogether satisfied with the rubber centred damper, as they say it has insufficient Hysterisis loss to be really effective. A man in General | ||