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).
Modifications to address excessive clutch wear on the 13-MX car.
| Identifier | ExFiles\Box 13\7\ 07-page138 | |
| Date | 7th September 1932 | |
| x7300 TO R.{Sir Henry Royce} from Ms/Gry.{Shadwell Grylls} c. SS.{S. Smith} Wor.{Arthur Wormald - General Works Manager} c. S. Da.{Bernard Day - Chassis Design} c. Hy.{Tom Haldenby - Plant Engineer} Hdy.{William Hardy} Ms/Gry.{Shadwell Grylls}1/KT.7.9.32. P.II. CLUTCH. When 13-MX{John H Maddocks - Chief Proving Officer} car first went to France with the synchromesh gearbox, excessive clutch wear was experienced. Adjustment was required very frequently. For the second 10,000 miles, 15% stronger clutch springs were fitted (253 lbs against 220 lbs) which entirely overcame the trouble. At the same time we wish to incorporate a pedal as used on the L.H. chassis that gives .009 greater separation of the plates. Some of the lost motion in the mechanism we found was due to the fingers bending. We have therefore stiffened them as shown on Ms.666. The first two modifications have the disadvantage that the pedal pressure is increased by nearly 20%. We looked into the possibility of reducing this pressure again by allowing a greater travel of the clutch pedal by starting it level with, instead of below, the brake pedal. By doing this and increasing the length of the lever operating the trunnion shaft 17%, the pedal pressure is increased, with all the modifications, by only 3%. We recommend standardising these features as soon as possible, and have fitted them to 36-M, Bg's car. Parts altered :- Springs to Ms.652 Pedal to P.34379 Fingers to Ms.666 Lever to Ms.637. A standardisation sheet for these parts has been sent round. Ms/Gry.{Shadwell Grylls} | ||