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).
Analysis of torsional rigidity and vibration frequency in the transmission system and crankshaft.
| Identifier | ExFiles\Box 132\1\ scan0132 | |
| Date | 22th April 1939 | |
| -2- RM{William Robotham - Chief Engineer}/JRS.1/JH.22.4.39. In a chassis the torsional rigidity of the transmission system is much less than that of the short shaft to the brake and consequently the frequency of this vibration is below the frequency of the engine impulse for all normal operating speeds. Whilst it is obvious that the main vibration of the 1220 r.p.m. diagram is a 1½ harmonic it may not be so in other cases as for example the 3600 r.p.m. diagram. In such a case it is possible to confuse the investigation of the more important mode of vibration by amplitude partly due to a mode which does not influence the system during the running range in practice. From the damped curves (Fig.1) it is evident that that increased diameter crankshaft should be a little easier on the camwheel although the actual vibration stress in the material may be no less, but this is of less importance as it is in the safe range. RM{William Robotham - Chief Engineer}/JRS. | ||