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 investigating 25 HP engine flywheel vibration and the effects of balance weights.
| Identifier | ExFiles\Box 179\2\ img001 | |
| Date | 1st December 1931 | |
| ORIGINAL To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to Rg.{Mr Rowledge} Sor. c. to RE. R.{Sir Henry Royce} c. to By.{R.W. Bailey - Chief Engineer} Da.{Bernard Day - Chassis Design} 25 HP. FLYWHEEL VIBRATION. As suggested by R.{Sir Henry Royce} we have carried out experiments on a balanced crankshaft with our optical apparatus to measure the diminution in magnitude of the flywheel vibration due to balance weights. These weights balanced 95% of the crankshaft and big end. It will be seen from the photographs that the period at 2400 R.P.M. (3100 on road with gearbox) is considerably decreased by the balance weights. We have also investigated the effect of both static and dynamic unbalance in the flywheel. For the static unbalance we attached a mass of 41 gms. to the periphery of the flywheel at 1.T.D.C. The effect of this is to make all the vibrations worse both for a balanced and unbalanced crankshaft. The dynamic unbalance was effected by the arrangement shown in the accompanying sketch. For these tests the crankshaft was not fitted with balanced weights. We found that when an out of balance couple of 1 lb. in. at 7" radius was applied opposing the couple of No.6 crank, the vibration at 2400 R.P.M. almost entirely vanished. We think therefore that the balance weight on No.12 web has a similar effect. A similar couple applied in the direction of that of No.6 crank greatly increases the vibration. We shall try a car on the road with this amount of unbalance, and see if it is any smoother. We are also having a crankshaft and flywheel that has always been rough dynamically balanced on an Olsen machine with a view to seeing whether such a machine would be of use to us. Hs{Lord Ernest Hives - Chair}/H.Grylls. Photograph also att: | ||