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 Ethyl Export Corporation regarding the inconsistent knock rating and octane numbers of Koolmotor Alcohol Blend fuel.
| Identifier | ExFiles\Box 27a\4\ Scan127 | |
| Date | 30th May 1933 | |
| CABLEGRAMS: ETHYLPORT, LONDON. TELEGRAMS: ETHYLPORT, CHURTON. X1282 ETHYL EXPORT CORPORATION Incorporated in the State of Delaware, U.S.A. with limited liability. ABFORD HOUSE, VICTORIA LONDON, S.W.1 Telephone: VICTORIA 5520 Head Office: 135 EAST 42ND STREET NEW YORK, U.S.A 30th May, 1933. W. A.{Mr Adams} Robotham Esq., Experimental Department, Rolls Royce Ltd., Nightingale Road, DERBY. Dear Rm.{William Robotham - Chief Engineer}, Many thanks for yours of the 29th May enclosing details of Koolmotor Alcohol Blend. With regard to the question of knock rating, I have no doubt at all that they are probably supplying you with fuel of super knock rating, but according to the analysis of samples which have been picked up over the last 12 months in many areas, the knock rating has varied from as low as 65 to as high as 84 and in fact, there seems to be practically no uniformity at all. That is to say, while you may be enjoying Koolmotor of an Octane number of 84 you cannot depend upon picking up the same fuel in various parts of the country. I had word of a sample to-day which was picked up in the Hull area and which showed an Octane number of 76.5. This, of course, is quite good, but there is an appreciable difference between 76.5 and 84. The Armstrong-Whitworth knock testing unit always reads fuels on the high side. Also I do not agree with their statement that the universally recognized C.F.R. engine method for correlating Octane numbers with car performance is dependant principally on water jacket temperature. This is not the case, since the water jacket temperature is being kept substantially the same, i.e. 100°C, but they have introduced a mixture heating device between the carburettor and the cylinder, in order to heat the mixture to 300°F (150°C). As a matter of fact, this method using the high mixture temperature is very severe on the fuel, and practically all fuels, when tested under these conditions, show a decided drop in initial Octane value. I would expect Koolmotor, which shows say 85 on the Armstrong-Whitworth engine to show about 81 to 82 when tested under C.F.R. Motor Method conditions. Referring to their other letter which concerns the separation of the alcohol content. I quite agree that when one uses dehydrated alcohol, separation does not generally occur if proper storage facilities are observed, but they do not mention | ||