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 report and evaluation of the Scintilla Magneto 3786.
| Identifier | ExFiles\Box 48\2\ Scan002 | |
| Date | 31th August 1920 guessed | |
| SCINTILLA MAGNETO 3786. A.M.6. -------------------------- This Magneto is very well made and is of the Inductor Type, the permanent magnet being combined with the revolving armature. It is an exceptionally heavy armature and I do not think the ball races are sufficient to withstand any continual use at high speeds. The Rotor is already showing signs of wear and flash-burning after 4 hours at 4000 R.P.M. The material is far too soft and will in time leave a deep groove. It is exceptionally quiet throughout its range, even quieter than the Bosch post-war type. I am inclined to think that after running some time the armature would be inclined to come adrift. There is no check for the cam end to seat into and is only held by 4 screws. It is hotter than the Watford but nothing near the Bosch post-war, probably enough to avoid the loss which we experience at present with the Watfords, viz. 5 Hs.{Lord Ernest Hives - Chair} Safety Gap. 8½ m/m.{Mr Moon / Mr Moore} Lowest Speed. 5½ m/m Gap. Retard. 150 R.P.M. ( Advance. 100 R.P.M. Pressure Test. Plug Gap .025" at 1,000 R.P.M. Retard misses at 65 Hs.{Lord Ernest Hives - Chair} " cuts out at 75 Hs{Lord Ernest Hives - Chair} D ". Advance " " 70 Hs.{Lord Ernest Hives - Chair} " " " 90 " D ". Plug Gap .020" at 1,000 R.P.M. Retard misses at 85Hs.{Lord Ernest Hives - Chair} cuts out at 110 Hs{Lord Ernest Hives - Chair} D ". Advance " " 80Hs{Lord Ernest Hives - Chair}" cuts out at 100 Hs{Lord Ernest Hives - Chair} D ". After 4 hours at 4,000 R.P.M. the retard position had dropped 5½ m/m Gap ( Retard 200 R.P.M. ( Advance 100 R.P.M. Sft{Mr Swift}/JMW. R.R. 199 (250) (SD676) 9-7-17(I) M'Fld&Sons | ||