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 detail showing specifications for '4630 COMPRESSION'.
| Identifier | ExFiles\Box 170\2\ img023 | |
| Date | 7th May 1931 guessed | |
| 4630 COMPRESSION 3" 2" | ||