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).
To the Technical Committee regarding the cause and experimental analysis of 'Coronation Vibrations' in cars.
| Identifier | ExFiles\Box 25\3\ Scan038 | |
| Date | 31th January 1912 | |
| Copy. N10/B5212. Le CanadelHenry Royce's French residence. 31st January 1912. Members of the Technical Committee. Re Coronation Vibrations. I should imagine these vary in different cars. They appear to me to be generated by the uneven turning moment of the engine. This does very little harm except at certain critical speeds when the natural torsional period of vibration of the propeller shaft synchronises (in harmonics) with the impulse as with the crank-shaft. This seems to be supported by the following experiments:- (1) Removal of brake drum. (2) Alteration of speed at which it takes place by altering the weight of the brake drum (light higher speeds, heavy lower speeds) (3) Ditto by introducing greater flexibility between the engine and gear box, decreasing the speed. (4) Decreased by increasing the weight of the flywheel. [Handwritten note]: from a very slight amount but enough, please file FR (over) [Handwritten in margin]: X634 | ||