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).
Design change to Phantom III exhaust valve stems to address noise and breakage issues.
| Identifier | ExFiles\Box 96\2\ scan0093 | |
| Date | 23th December 1935 | |
| Rm{William Robotham - Chief Engineer} L SMITH X354 DY.{F R Danby} c. FHC. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Ws. E/JNR.{Charles L. Jenner}1/HP.23.12.35. Phantom 3 Exhaust Valves. Experiments have shown that when we increased the diameter of the valve stems the increase in weight demanded stronger valve springs, and has caused noise at the valve seats. We wish to revert to the original small solid diameter stems .343" dia. but to taper the stem where it joins up to the tulip shape. This will increase the section where the valve usually breaks. We send you herewith LeC.4889 showing this alteration which will cancel our instructions on LeC.4711. In regard to the inlet valve, this will have a .343" solid stem, the shape of the tulip being as before. We are about to make drawings on the same lines for the large bore Bentley and 25/29 HP. E/JNR{Charles L. Jenner} | ||