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).
Photographic study of a phenomenon at different rotational speeds.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan117 | |
| Date | 7th January 1931 guessed | |
| IV G 8 STATIONARY 2500 2600 2800 3200-h | ||