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 to The Lodge Plug Co. regarding the testing, dimensions, and ordering of various spark plugs.
| Identifier | ExFiles\Box 162\6\ img170 | |
| Date | 18th August 1932 | |
| X 4425 Challis. C. to ROY.{Sir Henry Royce} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}8/AD. August 18th, 1932. Mr. Bernard Hopps, The Lodge Plug Co. Rugby. Dear Mr. Hopps, 14 mm. car plugs. We have now given the 14 mm. 3-point car plugs HD.{Mr Hayward/Mr Huddy}14 a fairly extended test and so far are very satisfied with them. The dimensions of the cylinder head to which we propose to fit them as standard, have now at last been settled so that we are able to give you the reach and barrel length required with some degree of accuracy. You will recollect that previously we have been reluctant to fix any dimensions because the design was in a state of flux. We are sending you under separate cover a small K.L.G. plug which happens to be almost exactly what we want. We could with advantage do with another .1" on the reach but if this presents any difficulties with regard to making a plug to give equal results to the H.D.14 you have already supplied, we should like you to let us know. We are proposing to pass you an order for one dozen of these small plugs for experimental use and should be glad if you would let us know when you anticipate being able to deliver them. For supercharger work we have been running your A.15 aero plugs in our car engines with remarkably good results. We should like one dozen of these plugs and for the best results the reach should be increased at least .1" as the points do not come flush with the end of the plug. We are sending you under separate cover one of these plugs which failed on test. This is the only failure we have so far had. | ||