Close-up photograph of a fractured valve head.
| Identifier | ExFiles\Box 127\5\ scan0058 | |
| Date | 1st November 1940 guessed | |
| ", | ||
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).