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 of an inlet valve with a 30° seat and small diameter.
| Identifier | ExFiles\Box 182\M19\ img243 | |
| Date | 19th September 1931 guessed | |
| Hs{Lord Ernest Hives - Chair} 372 .450 +5 -5 .025 CHAMFER AT 45° ±10 ±20 1.930 DIA +22 -0 30° ±1/2 1.500 DIA +0 -10 1.680 DIA +22 OTHER DIMENSIONS TO E78493 INLET VALVE [30° SEAT SMALL DIA] PII | ||