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).
Experiments on flywheel vibrations in a 25 HP engine.
| Identifier | Morton\M13.2\ img015 | |
| Date | 24th December 1930 | |
| ORIGINAL To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to Da.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} 1/MJ.24.12.30. Y634. FLYWHEEL VIBRATIONS 25 HP. We have just carried out some experiments on flywheel vibrations under conditions in which the vibrations are greatly magnified. The light from a point source is focussed to come to a point on a screen after reflection by a mirror which follows exactly the vibrations of the flywheel. From the photographs we have taken it appears that the flywheel is responsible for a considerable proportion of roughness in the engine. We consider this method very useful for finding out when we really have removed the flywheel period either by a new flywheel or by a tail bearing. Due to the absence of the gearbox the speeds of the vibration are reduced by about 600 R.P.M. from the speeds observable on the road. The flywheel on 1V-G8 (Japan unit) ran quite true at 1000 R.P.M. The first period was at 1900 R.P.M. (no photo of this available). It then ran true up to 2350 where the main flood started. The amplitude of the 1900 R.P.M. period is about 1/3 that of the main period. We consider it important in connection with booms occurring as it does at a speed in constant use on the road. We deduce that the flywheel is also responsible for roughness below the main period at 3150 R.P.M. (on the road). The photographs were taken direct on to Bromide paper with an exposure of six seconds. On both engines the maximum amplitude is approximately .048" at the flywheel periphery. We have also tried this apparatus on 1V-G8 with no flywheel, the mirror being direct on to the crankshaft. A very small disturbance occurred at 2000 R.P.M. followed by smooth running up to 3850 R.P.M. where a considerable disturbance .030" approximately, was observed. Hs{Lord Ernest Hives - Chair}/H.{Arthur M. Hanbury - Head Complaints} Grylls. | ||