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 regarding an examination and analysis of returned E.26 and E.25 type spark plugs.
| Identifier | ExFiles\Box 162\4\ img284 | |
| Date | 25th March 1937 | |
| 60012 K·L·G Sparking Plugs Limited CONTRACTORS TO THE AIR MINISTRY, ADMIRALTY, WAR OFFICE & FOREIGN GOVERNMENTS. 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 25th March, 1937. Messrs. Rolls-Royce, Ltd., Derby. Gentlemen, For the attention of Mr. West - Rm{William Robotham - Chief Engineer}/Wst.8/AP. We have now received the six E.26 type plugs and the one E.25 referred to in your letter of March 19th and have made an examination of them. From what you say we understand that the E.26's have run for thirty-seven hours on the test bed. We presume that this is under full load and, though we agree that the electrodes are somewhat burnt, we would suggest that this is not abnormal under these conditions. Thirty-seven hours of full load running represents probably three thousand miles full out on the road and, under those conditions, point burning must take place. However, we are experimenting with different alloys particularly for earth points and we think the material which we are now using is likely to give better performance. With regard to the E.25 in which the insulator is broken, we can only say that this plug was made at the very start of our production when we had not learnt quite so much about the necessary pressure required to make a gastight joint as we have now. We are satisfied that the fracture has occurred as a result of over-stressing at the joint and was not due to any fault in the material. This has resulted in the insulator having been sent out in a state of distortion and some comparatively light blow has caused the fracture. This is literally the only fracture which we have seen up to date, but we are watching the position very closely. We | ||