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).
Vibration measurements for a continuous battery box support at different speeds, identifying critical axle speed tramping.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan126 | |
| Date | 9th January 1931 guessed | |
| 14.99 SHEET II CONTINUOUS BATTERY BOX SUPPORT MEASUREMENTS AS IN SHEET I 14.99 M.P.H 18.45 M.P.H 25.83 M.P.H 30 M.P.H CRITICAL AXLE SPEED TRAMPING | ||