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 from A.C. Sphinx Sparking Plug Company regarding previous orders and a new model of spark plug.
| Identifier | ExFiles\Box 79\2\ scan0184 | |
| Date | 22th August 1925 | |
| Copy ------- From: A.C.SPHINX SPARKING PLUG COMPANY LTD HET/AM Bradford Street, BIRMINGHAM 22nd August.1925 Messrs. Rolls-Royce Ltd. Osmaston Road, Derby Dear Sirs, SPARKING PLUGS Some little time ago you sent us two orders for plugs, namely:- No.40808 dated 9th March 1925 No.41250 dated 19th March 1925. We presume these were for test purposes in accordance with your usual practice. We are not taking the liberty of sending you twelve of our latest type plugs model B-11. These are a new development, and if you take one of them apart you will find that the gland nut is now incorporated with the insulator. This gland nut is sealed by a patent electrical process which ensures that the plugs shall be permanently gastight. You will also note that none of the closing down stress is now carried by the insulator, this stress being entirely absorbed by the gland nut which seats on to the solid copper jointing washer. This construction now has the advantage of easy detachability for cleaning purposes, and at the same time it is practically impossible to re-assemble the plug incorrectly. We are sending you our three point type believing that you have a preference for multiple firing points. - 1 - ENCLOSURE N°562 JJSTSG | ||