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).
Test results and modifications for EW6 Watford Magnetos with North & Sons.
| Identifier | ExFiles\Box 65\3\ scan0269 | |
| Date | 5th May 1928 | |
| X7791 EFC. ROY{Sir Henry Royce}/JT3/HP5.5.28. EW6 Watford Magnetos. Reverting to EFC2/T24.4.28 respecting certain EW6 type Magnetos returned to makers for necessary correction, referred to in Mx{John H Maddocks - Chief Proving Officer}5/T14.3.28. Messrs. North & Sons report that in accordance with our wishes they will not fit the new type of Cam Rings unless we inform them after completing test of the magneto's so fitted that we wish them to do so. With regard to magneto No.100084 makers have tried this machine on the leak test and find that it sparks regularly over the leaky gap, when fully retarded, at 250 R.P.M. and 240 R.P.M. on alternate leads. In the circumstances will EFC please say what you wish North's to do in the case of this magneto, and we await your reply. ROY.{Sir Henry Royce} | ||