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).
The use and effectiveness of balance weights on an engine crankshaft.
| Identifier | ExFiles\Box 14\2\ Scan061 | |
| Date | 1st November 1923 | |
| Hs{Lord Ernest Hives - Chair}/Tan5/ADS.11.23 contd. -10- obtrusiveness of the engine, apart from the use of rubber. (3) Balance weights. We have shewn that these are a slight improvement on the Chrysler, and we have the fact that they are now practically a standard feature on all American cars, together with their oft-repeated claims of increased smoothness for them. We think that in our case, when we tried counter weights and found them if anything worse, this was not a direct consequence of using them but an indirect one, in that the critical speed was not kept constant by a corresponding increase in stiffness. As a result we ran on to the various torsional periods sooner and more often, which is not altogether surprising. We have demonstrated on the motoring tests that balance weights definitely do what is claimed for them, namely reduce internal vibration of the crankshaft and crankcase. Apparently this improvement may or may not be appreciable inside the car, due to certain other variables. Saving the crankcase and bearings then alone amounts to a sufficient justification for including balance weights, and incorporating the appropriate increase in stiffness, we think that on the majority of cars, no matter of how many cylinders, an improvement in smoothness would be noticed as well. Anyhow it is no use testing any more counterweight | ||