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).
Hand-drawn sketch of a front expansion box.
| Identifier | ExFiles\Box 83\1\ scan0342 | |
| Date | 13th January 1937 guessed | |
| 6 B IV FRONT EXPANSION BOX. | ||