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 K.L.G. Sparking Plugs explaining the identification markings and heat ratings for sample plugs supplied for the Phantom engine.
| Identifier | ExFiles\Box 162\4\ img240 | |
| Date | 22th January 1937 | |
| WST. Ensure that we get Bentley plugs that do not run too cool. Rm{William Robotham - Chief Engineer} K·L·G SPARKING PLUGS Limited CONTRACTORS TO THE AIR MINISTRY, ADMIRALTY, WAR OFFICE & FOREIGN GOVERNMENTS. 60018 Sole Manufacturers of 'KLG' Sparking Plugs, also Jigs and Precision Tools PUTNEY VALE, LONDON, S.W.15 Telephone Putney 2671 (Four Lines) Telegrams 'Kaelgee' Phone, London. PLEASE REFER TO TECHNICAL DEPT. AND QUOTE REFERENCE CMC/MEN IN YOUR REPLY 22nd January, 1937. Messrs. Rolls-Royce, Ltd., Derby. Gentlemen, For the attention of Mr. H.E. West. Experimental Dept. Rm{William Robotham - Chief Engineer}/Wst.13/JH. In reply to your letter of January 21st, the numbers which you found marked on the sample Corundite plugs are that of a code which tells us the date of manufacture and is allied to our furnace records. We propose to keep this in operation for some little time so that we can know whether there is any difference in the performance of plugs which have come from different firings. Unfortunately it was impossible for us to stamp the first consignment of plugs with their identification marks as the necessary stamps had not been delivered to us at that time. These identification marks are made up as follows:- "F" will always mean 14 m.m. diameter thread. "L" will indicate long reach (i.e. 15 m.m.) "B" will indicate long barrel A small "x" at the end indicates that the plug is non-detachable. The figures in the centre represent the degree of heat resistance. For practical purposes the No. 30 represents a heat resistance equivalent to our K.1 and the No. 50 represents a heat value approximating to our K.S.5. Therefore, the plugs which have been sent to you are named F.30x, which means 14 m.m. thread, standard length of thread and barrel, heat resistance equivalent to K.1 and non-detachable. These we hope will be suitable for the "Phantom." | ||