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 showing top gear acceleration performance, plotting speed in miles per hour against time in seconds.
| Identifier | WestWitteringFiles\V\2January1931-April1931\ Scan021 | |
| Date | 28th December 1930 | |
| 189IV 28-12-30 TOP GEAR ACCELERATION 25 HP. 9/41 HYPOID 5.25 COMPN. MILES PER HOUR SECONDS 60 50 40 30 20 10 0 10 20 30 40 50 | ||