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 discussing the relative octane values of benzol mixtures and Ethyl petrol.
| Identifier | ExFiles\Box 150\1\ scan0086 | |
| Date | 29th November 1935 | |
| CABLEGRAMS: ETHYLPORT, LONDON. TELEGRAMS: ETHYLPORT, SOWEST. X1282 ETHYL EXPORT CORPORATION incorporated in the State of Delaware U.S.A. with limited liability. THAMES HOUSE, MILLBANK LONDON, S.W.1 Telephone: VICTORIA 5520 Head Office: 135 EAST 42ND STREET NEW YORK, U.S.A Private 29th November, 1935. W. A.{Mr Adams} Robotham, Esq., Experimental Department, Rolls-Royce Ltd., Nightingale Road, DERBY. Dear Rm.{William Robotham - Chief Engineer}, Many thanks for your letter of the 28th November. With reference to the relative octane values of benzol mixtures when compared with Ethyl, I am inclined to agree with you that a 50/50 benzol mixture, if the basic petrol has a reasonably good anti-knock value, i.e. between 68 and 70 octane, might be superior to an Ethyl petrol in some engines. As a matter of fact, the octane value of a 50/50 mixture, when ascertained under the standard C.F.R. Motor Method conditions, is around 79 to 80 octane depending, of course, upon the basic petrol used. In other words, the C.F.R. will rate such a mixture equal to Ethyl, but it is a fact that when correlating the C.F.R. results with those obtained with the same fuels in automobile engines, the C.F.R. appears to depreciate the benzol mixture somewhat. That is to say, such mixtures behave better in automobile engines than the C.F.R. engine would have one believe. I can, therefore, appreciate the points you make in your letter. As you are aware, the performance of any fuel is dependent upon the particular set of engine conditions and characteristics in which it is used. The only thing that I can say to offset this apparent superiority of benzol (!) is that it is not easy to obtain 50/50 mixtures unless you make an arrangement with the local garage, and it is certainly not obtainable on tap at the normal service station. Also, it is considerably more expensive than an Ethyl or No.1 grade. Again, it is possible that you may depreciate benzol somewhat when supercharging is considered, but between ourselves I do not think that this will necessarily be the case, having in mind that your cylinder heads, aviation and automobile, appear to give quite good results with benzol. Since I hope to come to Derby for your Departmental Dinner perhaps I could arrive a little bit early on Saturday morning and have a short discussion on this question. Incidentally, I would also like to | ||