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 S.U. Carburetter Co. Ltd. discussing the weakening of fuel mixtures under cruising conditions.
| Identifier | ExFiles\Box 121\3\ scan0097 | |
| Date | 28th November 1940 | |
| Printed Text: THE S.U. CARBURETTER CO. LTD. PROPRIETORS:- MORRIS MOTORS LTD. ADDERLEY PARK, BIRMINGHAM, 8. TELEPHONE BIRMINGHAM EAST 1171 TELEGRAMS: FLEXCARBUR, BIRMINGHAM. VISCOUNT NUFFIELD CHAIRMAN W. M.{Mr Moon / Mr Moore} W. THOMAS VICE-CHAIRMAN T. C. SKINNER, M.I.A.E. MANAGING DIRECTOR YOUR REF: Rm.{William Robotham - Chief Engineer}6/ML. OUR REF: RLK/MRC. 28th November, 1940. W. A.{Mr Adams} Robotham, Esq., Messrs. Rolls-Royce Ltd., DERBY. Dear Mr. Robotham, Mr. Skinner has passed your letter of the 18th inst. on to me. We agree that under certain conditions a considerable weakening of the mixture under cruising conditions can be used. At the time we were investigating this matter the only engine we had available which would take weak mixtures was the Morris '10', which had very little overlap. On the Morris '8' which has more overlap weak cruising mixtures merely result in misfiring. On the Morris '10', with suitable modifications to the ignition arrangement, we did run as weak as 20:1; this engine, when warmed up, will give its maximum power at ratios very close to 15:1. The pulsations produced a degree of weakening of between 1 and 2 ratios, and this degree of weakening could be made use of without modification to the ignition. Additional weakening to the limit, combined with ignition alterations, provide a gain in specific consumption of 4½% as an average on 3/4 load, approximately 3% on 1/2 load, and nothing at all on 1/4 load. Averaging out over total running this Ctd. Handwritten Text: Rm{William Robotham - Chief Engineer}/CGS Please note File Carburettors C.V. Thus P [initial] 1031 OK bH | ||