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 for an Inlet Valve (PII) with a 30° seat and small diameter.
| Identifier | ExFiles\Box 92\2\ scan0148 | |
| Date | 2nd October 1931 guessed | |
| Hs{Lord Ernest Hives - Chair} 372 .150 +-5 .025 CHAMFER AT 45° +-10 +-2° 1.680 DIA +-2 1.500 DIA +-10 1.830 DIA +-2 OTHER DIMENSIONS To E75493 INLET VALVE [30° SEAT SMALL DIA] PII 30° +-1 1/2° | ||