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).
Engine vibration issues and potential solutions involving balance weights on a 25HP engine.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan360 | |
| Date | 19th August 1931 | |
| HS.{Lord Ernest Hives - Chair} ) FROM R.{Sir Henry Royce} DY.{F R Danby} ) C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} 25HP. - BALANCE WEIGHTS. R1/M19.8.31. x5010. x634. (1) The car brought to WW. on the18th., had 12 units of balance weight = crank and big end, which certainly increased smoothness, but I thought too dangerously near the master period. (2) We are not sure whether it is the crankshaft or the crank-chamber deflecting which is causing the flywheel wobble. If it is the crankchamber we can with the type used by Chrysler take all the horizontal bearing forces away, and this is the nearest way of proving which is the chief cause of the vibrations. Chrysler uses the 12 weight, 8 unit scheme. This might include crank and big end, and not be too low in master period. If still too low we must be content with less. (3) The master period must be high enough so that the valve springs allow valves, to jump well before master period, and yet not spoil top gear running, either by the falling off of power, disagreeable noise, or valve spring breakage. (4) Whatever the cause it will be seen that the easiest way of stopping the flywheel vibration is the WW. suggestion of a thinner web with a bearing in the gearbox. (5) WW. sends (today) our ideas for temporary and permanent ways of applying the 12 weight 8 unit scheme. (6) You will see that we have changed our views on this subject by sleeping upon it. My impression is that evidence suggests the possibility of the 6th. bearing moving about in opposition to the 7th. horizontally, so allowing the crankshaft to deflect and wobble the flywheel, and not so much the bending of No. 6. pin. This we want you to prove quickly, and anyway get the best scheme going, firstly to save the bearing, and secondly to smooth the engine. R.{Sir Henry Royce} | ||