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).
The testing, issues, and modifications of Watford IS.12 aero magnetos.
| Identifier | ExFiles\Box 43\4\ Scan118 | |
| Date | 7th May 1928 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. E.{Mr Elliott - Chief Engineer} c. Rg.{Mr Rowledge} Wor.{Arthur Wormald - General Works Manager} c. BV. V4021 EFC5/T7.5.28. PRESENT POSITION OF WATFORD IS.12 AERO MAGNETOS. V4021 We have had for test in all eight magnetos (four pairs) Air Ministry property. Nos. 83119/20, 83132/3, 83134/5, 83136/7. These were originally fitted with black synthetic moulded distributors which proved unsatisfactory on test. We also had trouble with contact points burning due to insufficient protection from oil vapour and in two cases we had contact breaker lever spring breakages. Messrs. North modified the first two pairs to rubber base distributor mouldings to cure the tracking trouble but as these magnetos were arranged with only 15° range they were never tested completely on the engine. We understand that the newer Watford aero magnetos are provided with an extra oil seal to prevent the burning of the platinum points. Of the other two pairs of magnetos, Nos. 83134 and 83137 did a considerable amount of running on a development engine before being replaced by 30° range B.T.H. aero magnetos. Tests have since been temporarily suspended until Messrs. North could submit magnetos generally more reliable and with 30° range. We have written Messrs. North on the subject and we attach a copy of the letter, which letter explains our position at the present with respect to these particular magnetos. EFC. | ||