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).
Letter discussing the performance of friction type dampers versus flexibly driven 'Harmonic Balancers' for eliminating torsional vibrations.
| Identifier | ExFiles\Box 25\3\ Scan205 | |
| Date | 20th December 1926 | |
| X634 Expl: Dept: Hs{Lord Ernest Hives - Chair}/ACLL/LG. 20th. Dec. 1926. 111, Grosvenor Rd., London S.W.1. Dear Mr. Kennington, We thank you for your letter of the 16th.inst. and for arranging with Mr. Summers to answer our questions re. the Harmonic Balancer. We have written Major Carter asking him if he would supply Mr. Summers with a copy of his report dealing with elastically driven dampers and expect to hear from him in the course of a day or so. As you know, we employ the friction type damper which gives us good and consistent results over our normal working speed range. The main synchronous speed on our engines is outside the normal working speed and although the friction type of damper is ineffectual at this speed, it proves to be particularly effective in removing the torsional vibrations due to harmonics of the engine torque which would otherwise be present at submultiples of the synchronous speed. Therefore getting rid of these vibrations to the extent that they are unobservable over a speed range which we are constantly using is of far more importance to us than the elimination of the main synchronous vibration which normally we never reach. The reason why we are investigating other types is that the flexibly driven damper - which in effect the 'Harmonic Balancer' appears to be - is an entirely different method of overcoming torsional resonance and while we understand it eliminates the main synchronous vibration - which in this respect is a definite advantage over the friction type of reasonable dimensions - we are not yet quite sure contd :- | ||