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).
Depot sheet detailing modifications to the Phantom III clutch by fitting lighter thrust springs.
| Identifier | ExFiles\Box 93\3\ scan0446 | |
| Date | 15th July 1938 | |
| To Hd.{Mr Hayward/Mr Huddy} FOR DEPOT SHEET. c. By.{R.W. Bailey - Chief Engineer} 312 Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler}5/MH.{M. Huckerby}15.7.38. P.III CLUTCH. It has been found that fitting lighter thrust springs which reduce the total thrust on the pressure plate by approx. 17% provides smoother engagement with less risk of judder, in addition, the pedal pressure is materially reduced. It is recommended that when ever a clutch is dismantled for any reason, the existing springs G.82591 be replaced by the lighter springs G.85733, coloured RED in all cases where no packing ring is fitted between the flywheel and the clutch cover, but where a .070 packing ring is fitted use spring G.85733 coloured YELLOW (which produces the same total thrust as the red spring without a packing ring). It will be necessary to examine clutches to see whether or not a packing ring is fitted as no record has been kept. Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler} | ||