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 Hubert HP Trist & Co. regarding sample orders, expenditures, and results of brake lining tests related to squeak.
| Identifier | ExFiles\Box 140\4\ scan0148 | |
| Date | 22th January 1938 | |
| 1181 xxx 2424. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}2/MH.{M. Huckerby} 22nd. January 1938. Messrs. Hubert H.P.Trist & Co., Top Dgg Works, Brislington, BRISTOL. Your Ref: BED/J.R/12,203. For the attention of Mr.Draper. Dear Sirs, In reply to your letter of 19th. inst., we note that, as we did not discuss prices of samples at the beginning, we have incurred an expenditure of about £15, without realizing it. We are only sending an order for the T.S.M/B and B.W. types, and in about one months time, when we will be nearing the end of the tests on these two types, we will order the remainder. If you will kindly hold the samples for us until then, it will simplify our accounts as we have been incurring rather heavy expenditure in the writer's experimental section, this month. Reverting to our letter Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}6/R.{Sir Henry Royce} dated 24th. March 1937, you may remember that we spoke of the importance we attach to the shape of u-speed curves in relation to squeak. We have got our test rigs running again and we have been able to show, on a Thermoid lining, that when a brake squeaks the coefficient of friction rises as the speed falls, and when the lining is in a state (slightly warm) in which it has never been known to squeak that the coefficient falls as the rubbing speed falls. From energy considerations one would expect this to be so, but this is the first time that we have demonstrated it. | ||