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).
Visit to K.L.G. to discuss failures and design improvements for Corundite insulated aero sparking plugs.
| Identifier | ExFiles\Box 162\5\ img020 | |
| Date | 9th June 1937 | |
| Sg.{Arthur F. Sidgreaves - MD} from Rm{William Robotham - Chief Engineer}/wst. Hs.{Lord Ernest Hives - Chair} c. E.{Mr Elliott - Chief Engineer} By.{R.W. Bailey - Chief Engineer} c. Lr.{Mr Ellor} RRC. c. Mx.{John H Maddocks - Chief Proving Officer} 60076. file Rm{William Robotham - Chief Engineer}/wst.8/AP.9.6.37 RE. VISIT TO K.L.G. I visited Messrs K.L.G.'s Works on Tuesday 8th inst., to discuss various failures experienced with the newly standardised 'Corundite' insulated plugs and also to discuss the progress of design on aero sparking plugs. The three troubles experienced up-to-date with the chassis plugs are:- (a) Rapid errosion of the electrodes. (b) Cracked insulators. (c) Bad gas leakage. With regard to (a) Major Carington stated that he is hopeful that the experimental plugs with modified central electrodes now being tested in the Experimental Dept., will show a considerably reduced errosion as compared with the standard plugs. The modification is based on the theory that the cause of rapid errosion is the exposure of the spark gap beyond the end of the plug and the reduction in the total heat factor of the plug, causing the electrode to run much hotter than they did in the case of the old standard mica plugs. The projection of the spark gaps beyond the end of the plug is a help to better slow running and the reduction in the heat factor reduces the tendency to foul when leaded fuels are used. The modification to the central electrode consists of making the portion enclosed in the Corundite insulator of copper and welding a nickel tip to the end exposed to the cylinder gases. This feature is claimed to conduct the heat away from the firing point at a greater rate. It is interesting to note that this feature was the subject of a recent patent filed by General Motors Ltd. In addition to this electrode modification Major Carington has designed a 'Corundite' plug with platinum earth electrodes and a sample plug is promised next week. Judged by aero plug results this modification should help materially in the reduction of gap errosion but is likely to increase the cost of the plug by about 6d. continued | ||