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).
Summary of the present clutch position for the Phantom III, detailing troubles and friction materials.
| Identifier | ExFiles\Box 85\2\ scan0290 | |
| Date | 15th November 1936 | |
| THO 212 To E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Smth. c.c. to Hs.{Lord Ernest Hives - Chair} c.c. to By.{R.W. Bailey - Chief Engineer} c.c. to Da.{Bernard Day - Chassis Design} c.c. to Hdy.{William Hardy} File Rm{William Robotham - Chief Engineer}/Smth.39/AP.15.11.36. CLUTCHES. The following is a summary of our present clutch position:- PHANTOM III Present troubles are:- 1. Jaggers. 2. Heavy pedal pressure. 3. Squeaks. 4. Poor durability. 5. Dragging. 6. Noisy trunnion bearing. Dealing with each in turn:- 1. Jaggers (a) Friction Material - rubber bonded materials are very much better than resin bonded ones, for take up. We have tried two types, Raybestos "Rycoe" and Ferodo "No.6". "Rycoe" originally came from America, but the English Company have made some experimental pieces. It is impregnated with litharge to increase wear durability, but is 35% heavier than No.6. as a consequence. It also has Square weave and the result is that on Ph.III. it burst under centrifugal load unless well supported by rivets. Would be alright in this respect on present R.R. plate (we have one made up and have run it), but we could not trust English article at this stage of its development. Also litharge causes picking up of the flywheel and pressure ring as shown by the American Long plate on 38-MX.{John H Maddocks - Chief Proving Officer} Inertia and cost also against this material. We are at present using No.6. which has a slight tendency to pick up the metal friction surfaces, and is too easily destroyed - at first only by rubber sticking to pressure ring, and then by top ply of fabric being torn off. We had no alternative to using this, however, as at the time no other material would give a smooth clutch. continued. | ||