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. concerning the performance characteristics of brake linings in relation to squeaking and juddering issues.
| Identifier | ExFiles\Box 140\4\ scan0143 | |
| Date | 20th January 1938 | |
| Messrs. Ferodo Ltd. -3- 20th. January 1938. extracted from the vibration and it will be damped out exceedingly rapidly, even if externally excited. This is all very obvious, and the only importance we attach to our recent measurements is that we have shown that :- (1) A lining can have, at times, a non-squeak characteristic. (2) That the "non-squeak curve" only occurs when the brake is not in a squeaking condition and that the "squeak producing curve" is associated with squeaking conditions. Before the war friction linings had a marked fall in μ as the temperature rose but chemists worked to alter this, with yourselves in the forefront, and now they seem able to produce any μ-temperature curve they want. It is not inconceivable that they could equally produce any μ-speed curve by the same method of attack, and we are firmly convinced that not until they produce a lining with the correct μ-speed characteristics under all conditions, will squeaks cease to exist. The first manufacturer to do this is going to have the same pull in the commercial world as you have in the racing world with your V.G.90. We hope that you have read this far and that we have explained the situation clearly. In conclusion, we would repeat that our theories have led to a most gratifying result in the case of dry judders and that our Management has willingly spent large sums of money on the mechanism our theories have led to, in order to be quit of the complaint, and that we can see no reason why an equally satisfactory result should not be obtained in this other matter. Yours faithfully, for ROLLS-ROYCE LTD. | ||