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 heaters, thermostats, and warning lights.
| Identifier | ExFiles\Box 137\2\ scan0207 | |
| Date | 5th November 1938 guessed | |
| THE AC-SPHINX SPARKING PLUG Co., LTD. CONTINUATION SHEET No. 2. We may have to send you these Heaters with our standard fronts, but shall take an early opportunity of replacing them with a revised type which has had additional piercings in it to increase the air flow. If, however, we are able to get sufficient hand made samples through in time we will send you both types. The diameter of the spigot on the three special motors has been turned to 1.255", but as this leaves the walls very thin we would not care to go into production with the casting as at present, and should wish to make the die casting 1.375" skimmed to a finished size of 1.33". Thermostats. It looks as though there would be no difficulty at all in supplying you with thermostat elements to suit your layout RM.{William Robotham - Chief Engineer}412, and we are sending you a blueprint of the article which we have at present in production. As regards your layout E.CD.210, it is not quite so clear just how it would best be adapted, and we should like your suggestions when you have received our detail, bearing in mind if possible that we should, of course, like to make the minimum change to our standard article. Warning Lights. We are enclosing blueprints showing our oil pressure switch and one of our oil pressure warning light assemblies. In addition, we are sending you samples of both, together with some unassembled parts, so that you can see the exact construction. As regards the warning light to record water temperature, we would like to say that up to the present we have not put anything into production, although we did make up an experimental model incorporating a proprietary temperature control switch which is sealed into a glass bulb. This seems to work very satisfactorily, and could doubtless be put into production with a very small amount of alteration. If you are seriously interested in this device we can arrange to make you hand made samples, and we believe that there would be no difficulty in obtaining good operation, except for the point which was raised by the manufacturers of the thermostatic switch at the time we were experimenting, and that was the difficulty of calibrating the switches within very close limits. We believe that they in their production sort out switches according to their tested calibration after manufacture, and then used them for their various customers who were asking for different calibration limits. Perhaps you would be good enough, if interested, to tell us within what limits you think the switch ought to work. The drawing we are sending you is very much of an experimental nature, and in any case will probably have to be changed in detail to suit your requirements of screw thread, etc. Yours faithfully, THE AC-SPHINX SPARKING PLUG CO. LTD. D.{John DeLooze - Company Secretary} BROWNE. Chief Engineer. | ||