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).
Laboratory report on tests conducted on new and used friction rings for a 20 HP clutch.
| Identifier | ExFiles\Box 103\1\ scan0010 | |
| Date | 20th January 1933 | |
| X 5300 To Hs.{Lord Ernest Hives - Chair} HL1/AG.20.1.33. Laboratory. Report No.L2595. RE - FRICTION RINGS - 20 H.P. CLUTCH. We understand that trouble has been experienced with slipping clutches. One new and one used friction ring were supplied to us and the following tests were carried out. Heating Test. This consisted of gently heating a piece of each ring over a burner, afterwards heating strongly. The new ring showed little change until heated strongly, when the bonding material caught fire. The used ring showed oily exudations, on the contact side, when heated gently. Further strong heating caused the material to take fire. Extraction. A weighed piece of each ring was heated for 5 hours in a solvent capable of removing oily matter from the rings. The loss in weight after this treatment was noted. New Ring. Used ring. Loss in weight % 2.54 3.54 A piece of the new ring, on heating to 100 - 120°C for several hours, began to show signs of darkening. We believe the bonding used in friction materials of this type is Tung Oil and it is possible that under conditions of moderate heat, this may creep to the surface, as noticed in the last mentioned test. The extra oil in the used ring may however have been introduced under working conditions. If you think a useful purpose would be served we could remove the oily matter from two new rings and return them to you for trial on a car. We return herewith one used ring labelled GAU7-48471 and two used rings labelled GAU44. Hl. JB | ||