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 detailing the test results of various servo friction disc linings from British Belting & Asbestos Ltd.
| Identifier | ExFiles\Box 141\3\ scan0338 | |
| Date | 10th December 1934 | |
| X3409 Exptl. Dept. Hs{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}4/KW. 10th December, 1934. Messrs. British Belting & Asbestos Ltd., 59, Southwark Street, London, S.E.1. Attention - Mr. Dalmaine. Dear Sirs, We have now thoroughly tested the Servo Friction Discs with which you supplied us recently, both on our testing rig and on cars. We are sorry to say that although some of these linings have very constant /u characteristics they are unsuitable owing to squeaking. Below we give a summary of the results we have obtained with all the linings so far submitted by you. Mintex Lamina. Very constant coefficient of friction. "Running in" required not unduly long. Unsuitable because of violent squeaking. Mintex ZS (Not ground). Reasonably constant coefficient of friction. Long "running in" period required. Unsuitable because of squeaking. Mintex Moulded Rubber. Coefficient of friction falls 25% between atmospheric temp. and 330°F.{Mr Friese} Objectionable smell which may disappear with use (not ascertained). No squeaks obtained. Unsuitable because of falling /u. | ||