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 graph plotting multiple performance curves.
| Identifier | ExFiles\Box 180\M4\M4.2\ img029 | |
| Date | 19th May 1921 | |
| M 40 30 20 10 2000 2250 ROLLS-ROYCE, LIMITED PRINT ROOM. 20 MAY 1921 DERBY '19.5.21. | ||