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 the Royal Aircraft Establishment discussing sparking plug specifications and the effects of tetra-ethyl lead fuel.
| Identifier | ExFiles\Box 58\2\ Scan068 | |
| Date | 29th December 1933 | |
| G.16/859. 81812a. When Telephoning with regard to this letter please ask for Extension Number............111.. TELEGRAMS: Ballooning, South Farnborough. TELEPHONE: 361 Aldershot. ROYAL AIRCRAFT ESTABLISHMENT, SOUTH FARNBOROUGH, HANTS. All Stores to be addressed:- R.A.E. Siding, Farnborough Station, Southern Railway (L. & S.W. Section) All communications to be addressed to The Chief Superintendent. OUR REFERENCE: E&I/S.P.270/6. YOUR REFERENCE: Hs{Lord Ernest Hives - Chair}/Wst.4/MA. 29th December, 1933. Messrs. Rolls Royce Ltd., DERBY. For the attention of Mr. H.E.West. Dear Sirs, In reply to your letter of 13th December the specification dealing with tests for sparking plugs is numbered E.E.141, not E.E.341 as quoted in your letter. This specification is under revision for publishing as an Air Publication and we regret that spare copies of the original roneod issue are no longer available. If, however there are any points upon which you desire specific information, please let us know. As regards the use of tetra-ethyl lead fuel and its effect on sparking plugs, we note with interest the results that you have obtained with Stellite central electrodes. Where the lead element in the fuel is of high concentration, it is our experience that conducting deposits invariably form on the surface of the insulation whether the plug is of the mica or ceramic type. The effect is, however, generally more marked on the former type of plug since in this case we get not only surface deposits but penetration of the mica laminae by those deposits. On the other hand where the lead element does not exceed about 5 c.c's. per gallon of fuel, we find that the insulators of sparking plugs, irrespective of type, always exhibit a characteristic discolouration. (We presume | ||