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).
Two graphs comparing the acceleration performance of a 20 HP engine with different compression ratios and exhaust configurations.
| Identifier | ExFiles\Box 113\2\ scan0120 | |
| Date | 19th November 1926 guessed | |
| ACCELERATION ACCELERATION FT/SEC/SEC. ROAD SPEED M.P.H. HIGH COMP. 20 H.P HIGH COMP. 20 H.P. CUT OUT OPEN STANDARD 20 H.P. ACCELERATION HIGH V LOW COMPRESSION RATIO 20 H.P. VELOCITY M.P.H. TIME SECONDS HIGH COMP. 20 H.P. 5.4 HIGH COMP. 20 H.P. CUT OUT OPEN STANDARD 20 H.P. 4.6 | ||