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 Ferodo Ltd. regarding brake lining materials and research into brake squeak.
| Identifier | ExFiles\Box 140\4\ scan0136 | |
| Date | 18th January 1938 | |
| 1180. xx 2424. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}18/MH.{M. Huckerby} 18th. January 1938. Messrs. Ferodo Ltd., Chapel-en-le-Frith. For the attention of Mr. J.N.Longley. Dear Sirs, We are glad to hear that you have made us some material similar to Thermoid D.35.IH, and will use it when it arrives. We have instructed the shop to fit the VG.91 to one of our cars. We enclose a graph which may be of slight interest. We have got our two test rigs working again, and have succeeded in correlating the shape of the μ-speed curve with the occasions when squeaks occur, very definitely. We have done this in various ways. The graph we enclose is a good example of the two possible curve forms. The left hand graph is the non-squeak one. This is why we feel that the ultimate solution of the squeak problem lies with friction lining makers, and that when they can produce a lining having a μ-speed curve similar to the left hand one on our graph under all conditions, then squeaks will cease to trouble us. Quite probably you disagree with this, but we are making considerable efforts in co-operation with brake lining manufacturers to achieve this end. Yours faithfully, for ROLLS-ROYCE LTD. | ||