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).
Letter discussing magneto ignition issues, spark plug oxidisation, and a proposed solution using a Delco switch.
| Identifier | ExFiles\Box 37\1\ scan 119 | |
| Date | 4th August 1921 | |
| X3199 CC Mr. Belnap. Mr. Nadin. August 4, 1921. OY6-G4821. Dear Hives:- X.699 - RE IGNITION X.430. X.3199 I am trying to catch up with your past letters which have remained unanswered. Your letter Hs{Lord Ernest Hives - Chair}1/LG5.5.21 on magnetos was most interesting to us, and has been read by interested members of the Engineering Committee. Regarding page 5, where you suggest that the spark has to have a certain value to ignite the charge, this is borne out by Dickinson in the "Journal" for May (page 484) in which he states that from test, by gradually increasing the intensity of the spark in a cylinder which is being fed with fuel mixture, the charge will not fire as long as the spark is too weak, but at some point will begin to fire irregularly, and later regularly. We have found that the Champion plugs appear to oxidise at the points a little after a short time and one gets missing on the pick up on magneto ignition. Our suggested cure is not to have special three point plugs made up (which would never stay in the car long because each chauffeur has silly ideas of his own on plugs, and which could not be obtained readily in remote districts) but to work both magneto and battery ignitions together, with the Delco instrument board control switch which we are sending you, cutting out the steering column switch and substituting a Klaxon button on top of the steering column. We believe this procedure, which you suggested in the first place, would get rid of 90% of our so-called "Slow running" complaints of customers. Also, should it later be permitted to abandon the magneto and use dual auto-advance battery ignition, no change would be necessary in the switching arrangements except that the earthing contact in the Delco switch would no longer be necessary. OY. | ||