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).
Note regarding sparking plug voltages on the 20/25 chassis, referencing another report.
| Identifier | ExFiles\Box 58\1\ Scan171 | |
| Date | 9th February 1931 | |
| X.5970. 9.2.31. Regarding the sparking plug voltages operative on the 20/25 chassis see a report EFCl/ADl7.12.30 in X.5680. | ||