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 the Vacuum Oil Company discussing the properties of Mobiloil 'EP' and comparative performance figures for other oil grades.
Identifier | ExFiles\Box 145\1\ scan0161 | |
Date | 6th April 1936 | |
X1229 BY APPOINTMENT VACUUM OIL COMPANY LIMITED GARGOYLE REGD. TRADE MARK TELEPHONE WHITEHALL 1010 (14 LINES) TELEGRAMS VACUUM PHONE LONDON CAXTON HOUSE . WESTMINSTER LONDON S W 1 REFERENCE ED{J. L. Edwards}/AUTO 6th April 1936 Messrs. Rolls-Royce Limited, DERBY For the attention of Mr.S.H. Grylls Dear Sirs, In reply to your letter of the 3rd instant reference Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}10kW we confirm our telephone conversation this morning. We presume the 10 gallon drum of Mobiloil "EP{G. Eric Platford - Chief Quality Engineer}" to which you refer was that which we delivered to you in February of this year, and if this is correct, you may rest assured this is the latest oil. Mobiloil "EP{G. Eric Platford - Chief Quality Engineer}" is of perceptibly heavier body than engine oil, and in fact, is nearly as heavy as our Mobiloil "C" which is of course, a fairly heavy gear oil; however, it is certainly not too heavy in body for the average conditions found in back axles, and we believe it will give excellent results in the Bentley axle for which we understand you are using it on test. We learn from Mr. J.Russell Sharp that when he was at Derby on the 3rd instant, you requested comparative figures for the performance of Mobiloil "D", "BB" "A" and Arctic. You will remember that we attached figures for these grades to our letter of the 11th February and we believe that the results of the tests on the National Physical Laboratory friction testing machine contain as much information as it is possible to give on this matter. Admittedly, these tests are carried out under certain standardised conditions which do not necessarily bear very close comparison with the average motor car engine, but some such standardisation is essential in comparative work, because there are a large number of variables which influence results in everyday use. In allowing us to use these figures, we believe the N.P.L. consider that they represent to some useful degree what may be termed the figure of merit of the oil, but it will be evident that there must be variations in the results due to the rate of oil feed, material from which the bearings are made, rigidity of mounting, and other factors, well known to be important in the design of a modern engine. Yours faithfully, VACUUM OIL COMPANY LIMITED AD/AH Chief Engineer. UNLESS STATED OTHERWISE ALL OILS ARE QUOTED AND INVOICED PER UNIT GALLON OF 9 LBS AND ALL QUOTATIONS ARE WITHOUT ENGAGEMENT. | ||