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).
Performance report on four Watford Aero Magnetos, type IS.12, detailing issues and run times.
| Identifier | ExFiles\Box 43\4\ Scan084 | |
| Date | 25th August 1927 | |
| X4021 25.8.27. WATFORD AERO MAGNETOS TYPE IS.12. No. 83119. This magneto has run a considerable time on one of our experimental engines and has been reasonably O.K. No. 83120. This magneto ran a short time on an engine and failed owing to the contact breaker spring fracturing. No. 83132. Bad advanced performance; otherwise O.K. No. 83133. Ditto. EFC. | ||