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 change in standardized sparking plugs by the Champion Sparking Plug Co.
| Identifier | ExFiles\Box 35\3\ scan 156 | |
| Date | 3rd April 1925 | |
| Hs.{Lord Ernest Hives - Chair} from ROY.{Sir Henry Royce} X4196 ROY{Sir Henry Royce}4/MG3.4.25 The Champion Sparking Plug Co. Mr. Craddock, their Sales Manager, states that Springfield have standardized these Plugs, and until recently used Champion Type A.I.R.64, but recently changed over to their later model known as Type No.8. The sample Champion Plugs you had were Type A.I.R 64. A sample of the later type now standardized by Springfield is attached. The Champion Company state that the difference between this and the former Plug is:- (a) Re-designed Insulator. (b) Shorter centre electrode (c) Re-designed Earth Wire and claim the above improvements absolutely obviate pre-ignition. ROY.{Sir Henry Royce} ENCLOSURE. Sample Plug Type No.8 ENCLOSURE Nº 722 JUSTSO | ||