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 Borg & Beck Ltd. detailing the unsuitability of their FF1 material servo linings after testing.
| Identifier | ExFiles\Box 141\1\ scan0027 | |
| Date | 13th April 1935 | |
| X3409 Exptl. Dept. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}2/KW. 13th April, 1935. Messrs. Borg & Beck Ltd., Tachbrook Road, Leamington Spa, Warwickshire. For the attention of Mr. Barker. Dear Sirs, Re 20/25 HP. Servo Linings in FF1 Material. We have been able to try the linings you gave us the other day and our servo rig. We find that cold they give a coefficient of friction of about .45 and that this falls at 200ºC. by 63%. This is an extremely high figure and means therefore that these linings are unsuitable for our purposes. The test conditions are, running with unit pressure on the lining of 100 lbs/sq.in. and a rubbing velocity of 46 ft/min. The test is continuous and the temperature of the nickel drum with which the lining is in contact is measured with a thermo couple. It may interest you to know that the Ferodo material VM.20 which you will remember we believed to be your standard lining, gives a 53% drop on this rig. The lining we have recently standardised is several times as good, with only a 17% drop when hot. We are not communicating with the Raybestos people, so if you think this information would interest them perhaps you would pass it on. Yours faithfully, FOR ROLLS-ROYCE LTD. | ||