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).
Comparative test report on Raybestos and Ferodo clutch fabrics for a 20 HP clutch.
| Identifier | WestWitteringFiles\J\February1923\ Scan51 | |
| Date | 16th February 1923 | |
| To R.{Sir Henry Royce} From Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to Ds. c. to BY.{R.W. Bailey - Chief Engineer} ORIGINAL. Hs{Lord Ernest Hives - Chair}1/LG16.2.23. RAYBESTOS CLUTCH FABRIC. X870 X3409 We have tested Raybestos fabric on a 20 HP. clutch. The rings were fitted to the makers instructions. We found that when the clutch was first fitted up we could reduce the total spring pressure from 960 lbs. to 640 lbs. The clutch would take up full load and not slip - we could make it slip and it would pick up. We found, however, as soon as the clutch had been heated up by slipping, it would not take the drive, it slipped continuously. After a severe slipping test, the raybestos had worn badly - when dismantled we removed a large quantity of powered material. We carried out a similar test with the present standard Ferodo we are using and found that this would hold the load with the same spring pressure as the Raybestos i.e., we could reduce the pressure from 960 lbs. to 640 lbs. and it would still hold on this particular clutch. It had the advantage also that the coefficient of friction did not disappear when it got hot. The condition of the Ferodo at the conclusion of the test was infinitely better than the Raybestos. From the results of our comparative tests, the Ferodo material proved itself to be superior to the Raybestos. We still, however, have got to find the reason why the coefficient of friction for Ferodo is less than the contd:- | ||