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 performance of a modified Watford IS12 magneto after bench testing.
| Identifier | ExFiles\Box 43\4\ Scan296 | |
| Date | 18th July 1930 | |
| E.7.C. X4021. Date 18-7-30 Ref No. WE32. X Nos. 4021 Watford IS12 magneto No. 98034 ex type test engine No. F14 MS.39. We have now received this magneto back from Messrs North and Sons after modification to improve the electrical performance. The modification appears to be, from external observation, the fitting of a new armature unit! Upon testing this magneto on the bench using metal braided H.T. cables we found the electrical performance considerably improved, the low speed sparking figures on 5.5 mm gaps now being:- advance - 140 r.p.m. retard - 320 r.p.m. The previous low speed sparking figures were :- advance - misfires retard - 1000 rpm. The normal and high speed performance was also very good. HEwest. | ||