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).
Vibration testing of a lightened flywheel for a 25 HP unit.
| Identifier | ExFiles\Box 181\M13\M13.2\ img026 | |
| Date | 13th January 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to Ss.{S. Smith} 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} ORIGINAL x634 25 HP. VIBRATIONS. We can now report on the behaviour of the W.W. lightened flywheel on 1V-G6 unit as recorded by our optical apparatus. The effect of this flywheel is to raise the worst period about 300 R.P.M. which would be equivalent to 10 M.P.H. in top gear (i.e. up to 73 M.P.H.). The road speeds of this vibration would therefore be 73 M.P.H. in top gear or 50 M.P.H. in third). As will be seen from the photographs the flywheel (with no gearbox) commences to vibrate at 2500 R.P.M. attaining a maximum at 3050 after which speeds vibration of a lesser degree than at the greater amplitude persists up to any speed. A record at 3500 R.P.M. shews this amplitude. We then ran this flywheel with a ball race tail-bearing under this condition. No vibration took place up to 2900 R.P.M. where a small vibration started having a maximum at 3100 R.P.M. Judging by relative amplitudes an improvement is to be gained by supporting the flywheel at the back. We have also tried a tail-bearing consisting of a bronze bush 1.3" long which ran our mirror holder (as shewn in accompanying sketch). The effect of this was identical with that of the ball race. No flywheel vibration took place up to 2900 R.P.M. where again a small vibration started about 1/3 of the amplitude of the 3000 R.P.M. vibration with no tail bearing. It continued up to any speed we could attain. Hs{Lord Ernest Hives - Chair}/H.{Arthur M. Hanbury - Head Complaints} Grylls. | ||