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).
Clutch failure on car 34-EX, and proposed modifications with Ferodo and Borg & Beck.
| Identifier | ExFiles\Box 96\3\ scan0090 | |
| Date | 27th September 1936 | |
| To E.{Mr Elliott - Chief Engineer} C. to Wor.{Arthur Wormald - General Works Manager} C. to By.{R.W. Bailey - Chief Engineer} C. to Da.{Bernard Day - Chassis Design} C. to EX. C. to Hdy.{William Hardy} C. to Roy.{Sir Henry Royce} Clutch Failure on 34-EX. One of the clutch facings (Ferodo No.6) has come loose on this car. It is evident that the material has spread outwards under centrifugal loading and the present arrangement of riveting has not been sufficient to restrict this movement. On discussing the matter with Ferodo and Borg & Beck it has been agreed that the best immediate remedy is to increase the thickness of the fabrics from .130" to .165" to mould the rivet holes instead of drill them, to cut all the T-slots in the centre plate at the outer diameter of rivet holes, and to fix both facings with all the inner rivets instead of each alternately, thereby fixing each disc with 18 rivets instead of 12. Ferodos are pushing ahead with the necessary dies for these modifications, and it is thought that we should be able to get deliveries of the new plates early next week. Meanwhile we have told Borg & Beck to continue to deliver plates to the old specification until advised to the contrary by the order office. The thicker discs will necessitate modifications to the clutch, and By.{R.W. Bailey - Chief Engineer} is looking into the question to see what is involved. We do not anticipate synchromesh troubles due to the thicker fabrics as the inertia will be increased by 12% only. We are experimenting with a plate in which we shall retain the original thickness but reduce the inner diameter of the facings by an inch, so that they overlap the ends of the T-slots in the centre plate. We shall then rivet both facings to the plate between the ends of each T-slot, thus doubling the number of rivets used at present. Ferodos are arranging to do centrifugal bursting tests on this and other discs. | ||