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 to The Dunlop Rubber Co. Ltd. explaining the inability to provide accurate figures for power loss in tyres and transmission.
| Identifier | ExFiles\Box 45\2\ Scan348 | |
| Date | 20th May 1931 | |
| 84050. Expl. Dept. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/KT. 20th May, 1931. The Dunlop Rubber Co. Ltd., Fort Dunlop, Erdington, Birmingham. For the attention of Mr. Healey. Dear Sir, With reference to your letter of May 2nd., we ourselves asked you the same question not very long ago. We have a lot of figures which we have obtained as to the power loss in our tyres and transmission, but in every case the tyres have been run on cast iron drums of a radius of , with the result that the figure we get is undoubtedly higher than it would be on the flat. Furthermore, to do the job satisfactorily we ought really to measure the power of the rear wheels - (1) Drive through the tyres. (2) The axle shaft connected directly to the dynamometer. Because, unless we do this we have no guarantee that the unit is giving the H.P. that it did on the test bench, neither have we exact figures for the transmission loss. Unfortunately we have no facilities for the measurement of power in this manner, and therefore we do not think we shall be able to give you any figures which would be sufficiently accurate to be of any use to you. At the same time we are very interested in this point ourselves, and if you conduct any tests, we should be glad to have the results. Regretting our inability to be of service to you, We are, Yours sincerely, For Rolls-Royce Ltd. | ||