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).
Graph comparing the acceleration of three different vehicle configurations against road speed.
| Identifier | ExFiles\Box 113\2\ scan0031 | |
| Date | 28th May 1937 guessed | |
| X1725 ACCELERATION TONS 4.G.II WT WITH PASSENGERS 1.625 6 EX " " " 2.15 I.G.I. " " " 1.4 ACCN. FT PER SEC: PER SEC. ROAD SPEED M.P.H. x 6.Ex. I G I 4 G II | ||