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. explaining an analysis of three types of brake vibration.
| Identifier | ExFiles\Box 140\4\ scan0141 | |
| Date | 20th January 1938 | |
| 118D Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}4/MH.{M. Huckerby} 20th. January 1938. Messrs. Ferodo Ltd., Chapel-en-le-Frith. For the attention of J.N.Longley, Esq. Dear Sirs, With reference to the visit of Mr. Harrap to these works, it appears to us that you have misinterpreted the graph that we sent you. May we explain, as briefly as possible, why we attach importance to it. We have had three types of brake vibration to deal with, i.e. (1) Wet Judders (2) Dry Judders (3) Squeaks. The first two we have dealt with, we know all about them, they need never occur again. The third still presents a problem. When dealing with these complaints we asked ourselves first "how is the energy of the rotating drum transmitted to the vibrating parts in sufficient measure to overcome the natural damping forces". In each case we assumed, and this applies to squeaks also, that the friction force was greater when the lining was rotating with the drum, than when rotating against it. Only this energy can be supplied to the cycle and this energy is :- ΣF1 x dx - ΣF2 x dx, cont'd.{John DeLooze - Company Secretary} | ||