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).
Car vibrations, crankshaft balance, and flywheel design in response to Mr. Gills' memo.
| Identifier | ExFiles\Box 137\4\ scan0230 | |
| Date | 25th February 1931 | |
| HSJ FROM R.{Sir Henry Royce} E.{Mr Elliott - Chief Engineer} (At Le CanadelHenry Royce's French residence.) C. to SG.{Arthur F. Sidgreaves - MD} NOR. C. to RG.{Mr Rowledge} BY.{R.W. Bailey - Chief Engineer} X634 R3/M25.2.31. CAR VIBRATIONS. CONCERNING MR. GILLS MEMO. To the weight of the crankshaft should be added the weight of all the other parts - i.e. crankchamber, bearings, etc.,- that have to be moved when the centre of the crankshaft runs out of truth, and also the ends should vibrate in opposite directions. But one feels this is not very important and naturally the stiffness however little it may be should reduce the deflection. It is manifest that balance weights are good if we can use them without bringing the laster period to low, because we ought to get- (1) A smoother engine because even a little less deflection, say 25%, would help. (2) Better life of bearings. (3) They permit slightly lighter flywheel. The memo. mentions that P. 2. flywheel which was lightened also had more flexibility in back plate. This probably just counteracted the lightening and left the flywheel period at the same speed. The over-run is not very manifest unless it is near 70 MPH. I have said that our boom at 65/70 MPH. is the same as yours (which I thought you mentioned as at much lower speed). We feel most here of torque reactions: they are more spread when vigorous. R.{Sir Henry Royce} | ||