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).
Experimental notes on engine flywheel vibration and its measurement.
| Identifier | WestWitteringFiles\U\August1930-November1930\ Scan090 | |
| Date | 2nd October 1930 guessed | |
| (1) Experiments on 12-34 have shewn that flywheel vibration existed at 3100 R.P.M. (43 M.P.H. in 3rd). At 3450 R.P.M. it had entirely vanished, the engine being quite smooth up to 3610 R.P.M. when the valves bounced. The flywheel runs most in truth at 937 R.P.M. in 3rd. gear. Out of Truth Parallel to Axis. On 12-34 the slow running out of truth is .003" or amplitude of this = .003"/2 At the period at 3100 R.P.M. the out of truth = .014"/2 Just below this period the flywheel moves slightly towards the front of the engine. It would therefore be interesting to do experiments with no end clearance in the back bearing. The vibration is more pronounced with the engine decelerating. On viewing these vibrations through the Rotoscape it was seen that the vibrations at right angles to the axis were greater than those parallel to the axis. The amplitude in this direction was measured by similar means (i.e. adjusting a screw up to the flywheel during the period and later measuring the gap at slow speeds between this screw and the flywheel). Out of truth at right angles to axis = .013"/2 All measurements were made at the top of the flywheel. By marking this with chalk it was found that the vertical displacement of the flywheel is a maximum 30° before T.D.C. of No.6 crank. The vibrations of the | ||