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 showing three numbered line schematics.
| Identifier | ExFiles\Box 137\4\ scan0383 | |
| Date | 27th August 1931 guessed | |
| 1., 2., 3., ∞ | ||