Photograph of bottom tappets from a Bentley SO No.1 Unit after 56 hours of running.
| Identifier | ExFiles\Box 124\1\ scan0011 | |
| Date | 6th March 1939 guessed | |
| BENTLEY SO No.1 UNIT. Bottom Tappets after 56 hrs. running. | ||
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).