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).
Blueprint showing a cross-section of smaller diameter valves for the Lighter Phantom Engine.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 50 | |
| Date | 30th September 1926 | |
| LIGHTER PHANTOM ENGINE — SMALLER DIAM VALVES - BOTH INLET & EXHAUST. 1.600 DIA RADIUS 1.750 DIA OCK/30/9/26 | ||