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).
Technical report on the effect of balance weights on flywheel wobble for Phantom II and 25 HP models.
| Identifier | ExFiles\Box 14\2\ Scan122 | |
| Date | 23th May 1931 | |
| Copy 7010 To R.{Sir Henry Royce} From Hs.{Lord Ernest Hives - Chair} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} Hs.{Lord Ernest Hives - Chair}5/MJ.23.5.31. X.634. X.5010. X.7010. BALANCE WEIGHTS P.2 & 25 HP. Effect of balance weights on Flywheel Wobble. PHANTOM II. On Phantom II although the pictures taken on the test bed shew that the flywheel wobble is at the same intensity as on the 25 HP., we cannot pick this period out when driving the car on the road. If we take all the P.2. cars we have tried on which we have an improved engine mounting, these have been remarkably smooth. We have no explanation for this, and it is one of the points which we have still to investigate. We have tried a P.2 with 12 balance weights, 6 balance weights (8 weight scheme), and no balance weights. As regards engine smoothness on the road we could tell no difference. As regards the master period, with no balance weights the master period is 100 m.p.h. with 6 balance weights the period begins to be felt at 80 m.p.h. with 12 balance weights it begins to become unpleasant at 80 m.p.h. It is rather unfortunate that the owner who drives his car fast and would gain the greatest advantage from balance weights reducing wear, is the one who would run into the master period. It would appear that the final balanced shaft for Phantom should be made much stiffer than the present one. 25 HP. The flywheel wobble on this car can be definitely felt on the road both by the driver and the rear passengers. For some reason which we cannot explain 'Japan' engines appear to be worse than 'China'. For instance, 16-G4, a car which we have just returned to W.W. is very much worse for flywheel period than standard production cars. 16-G4. had a new crankshaft fitted to it and at the same time the bearings were refitted, so we cannot attribute it to a worn bearing. On 16-G4, we tested this car first with 12 balance weights. The flywheel period could be felt, but one could get through it - it was over a small range of speed. We | ||