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 AC-Sphinx Sparking Plug Co. regarding an order and testing of experimental plugs for Bentley and aero engines.
| Identifier | ExFiles\Box 163\5\ img068 | |
| Date | 1st October 1936 | |
| TELEGRAMS: SPHINX, DUNSTABLE TELEPHONE: DUNSTABLE 360 PRIVATE BRANCH EXCHANGE THE AC-SPHINX SPARKING PLUG CO. LTD. DIRECTORS: N. F.{Mr Friese} STOCKBRIDGE, W. O.{Mr Oldham} KENNINGTON, C. J.{Mr Johnson W.M.} BARTLETT DUNSTABLE BEDFORDSHIRE OUR REF. NFS/GEB. YOUR REF. 1st October, 1936. Messrs. Rolls-Royce Limited, Derby. For the Attention of Mr. H.{Arthur M. Hanbury - Head Complaints} E.{Mr Elliott - Chief Engineer} West. Dear Mr. West, We have today received from your people their official order No. 25149 dated September 29th calling for fourteen type X399 plugs. As you know, this is the experimental plug which you are trying out on the Bentley - and as, when we were with you on Tuesday, you made no mention of requiring a further fourteen plugs, I am wondering whether this order has been sent to us to cover the experimental plugs of this type which you have already had. Alternatively, if your people really intend this as an additional order, I find that we have a further fourteen insulators of the type required and in that case we will make them into plugs and send them to you as soon as possible. Will you please look into the matter for me at your end and let me know? I confirm having handed to you on Tuesday last eight X(41)0 and six X(41)2 screened plugs for aero engine test, and I shall look forward to your test report on this job at the earliest possible moment. As I told you, both the double side electrodes as well as the central electrode on these plugs are in tungsten, and one point on which I am particularly anxious to have some information is the breakdown voltage of plugs with electrodes of this material as compared with the electrodes composed of materials more generally used hitherto. I gather that this aspect of the matter is becoming increasingly important, as higher altitude flying is required. With regard to the used Bentley plugs (X399) which we brought back here, these have been tested and they are all perfectly O.K. except for one, in which the insulator is fractured just over the top gland. MAKERS OF AC SPARKING PLUGS - AC AIR CLEANERS - AC PETROL PUMPS - AC PETROL GAUGES - AC OIL FILTERS - AC OIL GAUGES | ||