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 Dunlop Rubber Co. Ltd. inquiring about power loss in tyres as a function of transmitted power.
| Identifier | ExFiles\Box 45\2\ Scan208 | |
| Date | 17th January 1930 | |
| XC4050, Expl. Dept. Hs{Lord Ernest Hives - Chair}/An.1/WJ. Jan. 17th, 1930. The Dunlop Rubber Co.Ltd., Fort Dunlop, Erdington, BIRMINGHAM. Dear Sirs, For the attention of MR. Bond. A point has come up in connection with power losses in tyres as to whether the power absorbed by a tyre increases as the power it transmits increases. One would certainly imagine it would owing to the increased flexure of the tread. While you are making tests on the subject, could you include one to see if this is of any account. One of our rear tyres (7" x 21") transmits about 45 HP. at 70 m.p.h. at 35 lbs/sq. in. We should like to know whether the power it absorbs under these conditions is any greater than the 4 HP. which is lost when coasting. From some tests that we have roughly carried out here we believe that there is an appreciable difference of as much as 50%. Yours faithfully, For Rolls-Royce Ltd. | ||