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 Ferodo Ltd. discussing a clutch judder issue and the frictional properties of clutch facings.
| Identifier | ExFiles\Box 129\4\ scan0187 | |
| Date | 7th April 1938 | |
| 1160. Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler}7/JH. 7th April, 1938. J.N. Longley Esq., Messrs, Ferodo Ltd., Chapel-en-le-Frith. Dear Mr. Longley, All our experience appears to confirm the view which we have discussed that the frictional properties of a clutch facing undergo a change, usually after a few thousand miles, and this applies both to woven and die pressed facings, including Thermoid. We have an interesting case of this at the moment the history of which is as follows :- We fitted to an experimental Bentley a 10" Thermoid faced clutch during last July, the mileage to date being 11,700 and till quite recently the clutch behaved extremely well, when a judder developed and rapidly became worse, we therefore dismantled the clutch ( a Borg & Beck) and found one of the three fingers .018" out of adjustment, we naturally thought this would account for the judder, so re-assembled the clutch with the same plate after correcting the fault, but the judder returned in some 50 miles. The appearance of the facings was almost as new, excepting for a ring of darker colour, there was no measureable wear, and no sign of oil. We therefore fitted a new plate complete, taking care not to alter any other feature or condition, and found the operation of the clutch perfectly smooth and normal. We feel that it might be helpful if I came to see you with this plate, bringing also a new and unused one, so that we could discuss the matter generally, and possibly a microscopic or chemical examination might reveal the difference | ||