Blueprint diagram showing a cross-section of a valve spring plunger.
| Identifier | ExFiles\Box 152\2\ scan0007 | |
| Date | 6th July 1937 guessed | |
| FIG I VALVE SPRING PLUNGER | ||
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).