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).
Very faint technical diagram showing various angled lines with ratio annotations.
| Identifier | ExFiles\Box 34\3\ Scan170 | |
| Date | 23th April 1927 | |
| X2642 ROLLS-ROYCE, LIMITED PRINT ROOM 23 APR 1927 DERBY 7/1 5/1 3/1 2/1 | ||