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 to Gandy's Linings Ltd. regarding the development of a rig for testing brake lining squeak.
| Identifier | ExFiles\Box 140\4\ scan0173 | |
| Date | 14th February 1938 | |
| 1181 February 14th.1938. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}10/AP. Your Ref. I/U. Messrs Gandy's Linings Ltd., Wheatland Works, Seacombe, CHESHIRE For the attention of Mr.G.Ikin. Dear Sirs, With reference to your letter of 1st. Feb.1938, we have agreed to reline a car with both D.{John DeLooze - Company Secretary} and 400.M. and this is now being done. This system of testing the squeak propensity of linings or combinations thereof by trying them on a car is most unsatisfactory and laborious, and very limiting. Moreover, it gives no indication of why one lining is better than another. We are evolving a method of testing which not only rapidly measures the 'squeak value' of a lining, but by its nature shows why one lining is better than another. Ferodo Ltd. are so pleased by the idea of having a rig that measures squeak graphically that they are copying ours in order that they can undertake intensive development of a non-squeak lining. Describing briefly what we have done:- We assumed that the source of energy for the main-tenance of a squeak vibration was derived from either the static /u being higher than the slipping /u, or else from a /u speed characteristic such that /u falls as the rubbing speed rises. We then made a rig which will measure this /u speed characteristic and have been able to show that linings in the squeaking condition have a /u which falls as the speed rises, and conversely for a non-squeaking lining. continued | ||