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 F.M. Aspin & Co. Ltd. to W.A. Robotham discussing engine performance, fuel specifications, and compression ratios.
| Identifier | ExFiles\Box 134\1\ scan0247 | |
| Date | 6th April 1940 | |
| 1129 TELEPHONE - BURY 1554 TELEGRAMS - "NIPSA" BURY CABLES - " " " WESTERN UNION "NIPSA" BURY F.{Mr Friese} M.{Mr Moon / Mr Moore} ASPIN & CO. LTD. Chairman and Managing Director. F.{Mr Friese} M.{Mr Moon / Mr Moore} ASPIN Directors- T. B. ASPIN W. R.{Sir Henry Royce} CHOWN L. CLOUGH E.{Mr Elliott - Chief Engineer} RIDDEL G.{Mr Griffiths - Chief Accountant / Mr Gnapp} E.{Mr Elliott - Chief Engineer} VARLEY INTERNAL COMBUSTION ENGINES ELTON BURY ENGLAND YOUR REF Rm.{William Robotham - Chief Engineer}3/ML. OUR REF FMA/MA. 6th. April, 1940. W.A. Robotham, Esq., Rolls-Royce Ltd., DERBY. Dear Mr. Robotham, I am in receipt of your letter of the 27th ultimo, and regret not having replied to this earlier owing to my being absent from the office. With regard to your queries. I enclose drawing No. D 333 and D 432, one showing performance of the engine on town's gas and the other showing performance of the engine on 80 octane fuel with a barometer reading 28.5 ins. On a very good day we have read 161 M.E.P., although we should say that the readings we can obtain any and every day are as indicated. The fuel we ran on was 65% Pool Petrol and 35% Benzol, this we were given to believe from Shell-Mex and B.P. Ltd., should give us an octane number anywhere between 78 and 85. On pre-war number one petrol i.e. 70 to 73 octane it is possible to get audible detenation, but with the addition of a small proportion of benzol or by reducing the water temperature down to 110 degrees fahr, this disappears. The compression ratio is 13.6 - 1 with a long reach plug, and when motored at 360 R.P.M. with the engine warm, shows 400 lbs per square inch compression pressure. With the engine cold we have read as high as 410. Naturally as youwill see the maximum torque of the engine ALL COMMUNICATIONS TO BE ADDRESSED TO THE COMPANY | ||