Letter from Ferodo Ltd discussing brake lining performance, temperature, fade, squeal, and arranging a visit.
| Identifier | ExFiles\Box 121\1\ scan0358 | |
| Date | 6th November 1940 | |
| Brakes FERODO LTD CHAPEL-EN-LE-FRITH STOCKPORT ENGLAND Telephone CHAPEL-EN-LE-FRITH 250 (7 lines) Telegrams FRICTION PHONE CHAPEL-EN-LE-FRITH TECHNICAL DEPT. 6th November, 1940. Rm {William Robotham - Chief Engineer} /MHR {M. H. Rigby} 4/ET. WES/ET. Messrs. Rolls-Royce Limited, Experimental Department, D E R B Y. Dear Sirs, We have to acknowledge your letter of the 4th instant which was received today, and regret that our statement that a temperature of 300°C. could be regarded as harmless to most of our brake linings, was not sufficiently explicit. When we committed ourselves to saying that we expect any of our automotive brake linings to withstand the above temperature without harmful results to the lining, we should have qualified the statement to mean that after subsequent cooling it would still retain its normal rate of wear and its µ characteristic would be unaltered. We are agreed that most brake linings when once they are run-in have some degree of fade, but surely while this is certainly the effect of temperature rise, it is also the particular µ characteristic of that lining. If the fade curve does not alter during successive applications which each raise the drum temperature to say 300°C. it can hardly be said that temperature has changed the lining's friction properties. Brake squeal is in a category of its own, and we consider the only scientific explanation we have heard was that put to us by your Mr. Martindale. You may have seen from your records that we erected a squeal test rig here, in which both he and Mr. Dixon were interested, but it had to be temporarily dismantled when we were erecting the new test machines, and it was not subsequently re-erected owing to the outbreak of war, and the suspension of much of your experimental work. From the reference on your letter it appears to the writer that it has been written by Mr. Rigby, and as you now appear to be resuming experimental work on cars we think you might find it interesting to examine our new plant. If you would kindly telephone beforehand to ensure that the writer is at these Works we should welcome a visit from you, and suggest that you might find it convenient to arrive here about noon, in time for lunch at 12.30 p.m. We could discuss the type of programme you evidently have in mind, and see how far this can be carried out on our equipment. Yours faithfully, FERODO LIMITED. W.E.Shilton Manager. Technical Department. | ||
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).