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 drawing of an inlet valve with a 30-degree seat and small diameter.
| Identifier | Morton\M19\ img243 | |
| Date | 19th September 1931 guessed | |
| Hs{Lord Ernest Hives - Chair} 372 .450 ±5 .025 CHAMFER AT 45° ±10 ±2° 1.830 DIA ±2 30° ± 1/2° OTHER DIMENSIONS TO E78493 INLET VALVE [30° SEAT SMALL DIA] PII 1.500 DIA ±0 1.680 DIA ±2 | ||