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).
Hand-drawn sketch of a component's cross-section with notes on alternative materials.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan013 | |
| Date | 5th March 1929 guessed | |
| one or both frictional material instead of rubber rubber | ||