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).
Visit to Chapel-en-le-Frith concerning brake friction materials and squeaking linings.
| Identifier | ExFiles\Box 30\6\ Scan157 | |
| Date | 12th July 1923 | |
| R.R. 405A (40 H) (SL 42 12-7-23). J.H.,D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. 3409 REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LC17.T. 24. VISIT TO CHAPEL-EN-LE-FRITH. (1) We interrogated Mr. Field as to the possibility of their producing a friction material whose co-efficient did not vary with temperature - he thought such a material would be impossible to produce. (2) We also queried him as to variation in the co-efficient with increasing pressure - as he previously had written that this factor was not of much importance. He admitted that as increase of pressure was likely to cause a rise in temperature at the surface of the ferodo in the same way as increase of speed, that the two would probably have much the same effect on a brake where the heat generated may be taken to be directly proportional to the speed of rotation and the unit pressure. (3) Squeaking linings. We were told that on their test - Austin brake drum with cast iron shoes that they had never experienced either brake squeaks or scoring. Upon trying this drum, however, we obtained a squeak with the complete wrapping shoe, and with lining in the centre only of the same shoe the noise set up was positively alarming. With lining at the toe and heel of the shoe only, however, there was no squeak. We understand that they attribute brake squeaks to the rigidity of the material that they are using, and are testing for a cure by packing soft asbestos behind the hard lining before riveting in. One would think that this would tend to make the brakes spongy. (4) Variation of co-efficient of friction. They believe the major part of the variation in the co-efficient of friction of their materials under working conditions to be due to the contd:- | ||