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).
Battery ignition, distributor design, and pre-ignition prevention.
| Identifier | ExFiles\Box 52\3\ Scan324 | |
| Date | 30th May 1918 | |
| R.R. 255 A (100 T) (S.F. 846/8-5-19) G. {Mr Griffiths - Chief Accountant / Mr Gnapp} 2480 X. 2814 To EFC. {E. Fowler Clarke - Electrical Engineer} from R. {Sir Henry Royce} c. to CJ. 30th May 1918. R18/5/30518 X.3173 - RE BATTERY IGNITION X.3129 X.800 X.3296. X.3199 X.2814 X.1520. On the distributor sent on 49-CB I can see a slight sign of the secondary spark on the segment, which seems to occur just about one-eighth from the beginning end of the segment. I am pleased you have been able to arrange this type of distributor in accordance with my suggestion, so that it is with reasonable care, impossible to get a pre-ignition in the engine. This is very satisfactory, because it is so much simpler than the best known schemes, namely, that of the Delco Co., which we understand is not entirely proof against such a danger. It will be noticed that a wipe contact distributor would be far more difficult to arrange satisfactory, in the same way, on the principle, but if it were of sufficient diameter, in accordance with the number of cylinders, it could give a trailing brush in contact with a main brush, so that in the event of it fiting on the make instead of the break, by running backwards, it would occur in a cylinder already past the centre. This scheme demands that the distributor should be advanced with the contact maker. I have some doubt as to whether this is done in the Delco "Liberty" design, it seems awkward, unless one uses an advance on the drive, owing to the large numbers of loose wires it necessitates. | ||