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).
Report page detailing the results of experiments on the heat transmission coefficients of sparking plugs.
| Identifier | ExFiles\Box 58\2\ Scan132 | |
| Date | 14th June 1934 guessed | |
| F.I.M.A.C. MILANO -5- It can be concluded from the series of experiments carried out several times, and of which the average results were used, that 1.- Variation of the coefficient of transmission of heat that can be obtained with a C.F. sparking plug(in all the plugs existing at present, the coefficient of transmission in constant because the electrodes are made of one metal only, or two - steel or copper - in a mutually invariable position) fluctuates between: As ( pin detached) = 0,0297.........IInd test Ac (contact pin) = 0,0651.........IIIrd " to wit, it varies in the ratio of 1 to 2,194. 2.- The plug with the contact copper pin and that with the complete copper pin, have an equal coefficient of transmission(experim- ents N°3 & 5) and this goes to show that a contact with sufficient pressure does not cause any increase of resistance to the passage of the heat. 3.- A plug with the pin detached, has a coefficient of transmission of 0,0297, but without the copper pin, it has a coefficient of 0,0194 (experiment N°5) and the increase produced by the presence of the pin is therefore: 0,0297 - 0,0194 = 0,0093 This is the value of the quantity of heat sent through the layer of air between the copper pin and the electrode, but it is very little and shows how sufficient the distance of 1/10 is, existing between the two small copper heads. 4.- The test to determine the variation of conductivity in | ||