Letter from K.L.G. Sparking Plugs regarding the development and testing of a new experimental spark plug, number 765.
| Identifier | ExFiles\Box 162\4\ img002 | |
| Date | 28th April 1933 | |
| X19188. TELEPHONE: PUTNEY 2132 & 2133 TELEGRAMS: KAELGEE PHONE LONDON CONTRACTORS TO THE ADMIRALTY, WAR OFFICE, AIR MINISTRY & FOREIGN GOVERNMENTS CODES USED: A.B.C. 5TH EDITION, WESTERN UNION K.L.G. Sparking Plugs Limited MAKERS OF JIGS AND PRECISION TOOLS SOLE MANUFACTURERS OF K.L.G. SPARKING PLUGS ROBINHOOD ENGINEERING WORKS PUTNEY VALE · LONDON · S·W·15 IN YOUR REPLY PLEASE REFER TO TECHNICAL DEPT AND QUOTE REFERENCE CMC/MKN. 28th April, 1933. W.A. Robotham, Esq., Messrs. Rolls-Royce, Ltd., Derby. Dear Mr. Robotham, Referring to our conversation when I visited the Works on Wednesday, April 19th, we have now examined the No. 734 plug very carefully with a view to increasing its heat resistance and retaining the rather long reach which you require. As a result of this we have now made up a new type, of which the experimental number is 765. In this type we have followed rather more closely the lines of the K.1, which you are using as standard on the 25 h.p. car and with which I believe you are reasonably satisfied. The 765 plug has a core of valve steel which extends right through from the terminal to the firing point. This core is surrounded by a copper tube of extra heavy section which should prove a very good conductor for drawing the heat away from the inner end. The particular advantage of this construction is that it eliminates any possibility of the firing point becoming detached and falling into the cylinder. This is a trouble that we have experienced with inserted firing points and copper electrodes. I shall be very grateful if you will give these fourteen plugs which we are sending you to-night a test and let me know whether they are likely to be of any use. If they show promise I propose making up another set straightaway and sending them to Mr. Lappin who has asked me to let him have some. | ||
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).