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 from the Institution of Automobile Engineers discussing experiments on brake squeak, friction, and speed.
| Identifier | ExFiles\Box 121\1\ scan0073 | |
| Date | 9th November 1938 | |
| 1029 The Institution of Automobile Engineers. Great West Road. Brentford. Middx. TELEPHONE: EALING 4741/2. TELEGRAMS: EALING 4741. CGW/BT.{Capt. J. S. Burt - Engineer} Your Ref: Rm{William Robotham - Chief Engineer}/AFM{Anthony F. Martindale}5/R.{Sir Henry Royce} (IAE) AUTOMOBILE RESEARCH COMMITTEE. 9th November, 1938. Rolls Royce Ltd., Derby. For the attention of Mr. A.F. Martindale Dear Sir, I regret the delay in replying to your letter of October 24th, 1938, but I have been very busy since returning recently from the States. I was very interested to read of your experiments on the relation between friction and speed. As you remark, our friction curves do not bear out the theory that a falling friction-speed characteristic of the lining is responsible for brake squeak, but we are not convinced that this theory is not the explanation because it is difficult to think of any other source of energy to maintain the vibrations. I am interested to see that your curves are in agreement with the squeaking characteristics of the linings. It is possible that differences in the methods of testing may account for this. I am sorry that we have no photograph of the friction testing machine as altered for our tests at various speeds. The diagram in the Report, Figure 4, shows all the essential features of the apparatus. The chief difference between our method of test and yours seems to be that our tests were made at a series of constant speeds, while your tests were made with a continuously varying speed. | ||