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).
Research on crankshaft dampers for a 12-cylinder engine, with data obtained from General Motors.
| Identifier | ExFiles\Box 93\5\ scan0117 | |
| Date | 7th March 1936 | |
| x317 Hs{Lord Ernest Hives - Chair}/Smth. LE Smith. See me please Da.{Bernard Day - Chassis Design}1/HP.7.3.36. Pan Crankshaft Dampers. The information obtained from General Motors Research is - For a 12 cylinder engine:- Inertia - 10% to 20% of total inertia. Tuning - 55% of 6 per cycle period for the 20% inertia. 75% for the 10% inertia. The above applies to an harmonic balancer of the type with plate spring control. This damper, of course splits up the main period into two, one above and the other below it in frequency. Friction is that between the leaves of the plate springs. It must not be too great or it will magnify the lower period and if too little the higher one. If the springs are too stiff the lower period will be brought up, and if too weak the higher one. The greater the inertia of the damper, the lower the proportion of the 6 per cycle period to which it need be tuned. They shewed us curves shewing the superiority of the harmonic over the Lanchester damper in effectiveness for various proportions of inertia. For small percentages of inertia the former was very much superior, and though this superiority fell as the percentage increased it is still of the order of 2 and 1 at the greatest practicable proportions. Da.{Bernard Day - Chassis Design} | ||