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).
Specifications for drilling holes in shock damper valves for 20 HP, Phantom 1, and Phantom 11 models.
| Identifier | ExFiles\Box 105\3\ scan0085 | |
| Date | 10th December 1929 | |
| X5520. To Ey. From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Hn.{F. C. Honeyman - Retail orders} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}2/MJ.10.12.29. DRILLED SHOCK DAMPER VALVES. X5520 X7520 The 20 HP. H.P. valves are now being drilled with one .032" hole to avoid knocks. We recommend that if a larger hole is demanded, such as for instance a .055" hole for the Phantom 1 slow speed riding, it should be obtained by drilling more than one hole to avoid using a hole of greater diameter than .046". If a hole of greater dia. than .045" is drilled in the present valve it is liable to be partially obscured by the spring as will be seen from the attached drawing, owing to the spigot for the valve spring on the valve head being considerably smaller than the inside dia. of the spring. This gives rise to inconsistent results. We confirm that as yet no drilled valves have been standardised on Phantom 11 dampers. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||