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 Phantom valves, specifically increasing the stem diameter for inlet valves.
| Identifier | ExFiles\Box 17\6\ Scan034 | |
| Date | 26th April 1928 | |
| Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. BY.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} +7060 R1/M26.4.28. PHANTOM VALVES. X. 8060 X. 7060 We find the Phantom valve to be thinner in the tulip than any other valve we are now using irrespective of size, and I think there is very little doubt that it becomes entirely a question of design, and not material. We are sending you through a drg. Lec. 2551 - showing a modification to the head and stem. We are asking for the stem to be larger by an amount that we think can be got in on the present heads. The present stock of valves can all be marked 'inlet'. A difference in the stem diameter enables us to make the inlet valve stems a better fit than is obtained with interchangeable valves, and also avoids adding weight to the valve with the larger acceleration and reducing the max: speed of the engine. R.{Sir Henry Royce} | ||