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 Dunlop discussing high speed steering wobbles and tyre balance issues.
| Identifier | ExFiles\Box 28\4\ Scan333 | |
| Date | 24th August 1925 | |
| Telegraphic Address. "DUNLOPS, BIRMINGHAM". Telephone No. BIRMINGHAM CENTRAL 4108. PRIVATE BRANCH EXCHANGE. 25 LINES. Registered Offices. DUNLOP HOUSE, 1, ALBANY ST LONDON, N.W.1. BY APPOINTMENT DUNLOP RUBBER CO LTD Founders of the Pneumatic Tyre Industry FORT DUNLOP, ERDINGTON, BIRMINGHAM. STATION: CASTLE BROMWICH, (MID. RY.) GOODS: TO DUNLOP SIDINGS, CASTLE BROMWICH. CAR ROUTE: TYBURN ROAD from STEELHOUSE, LANE. TO FORT DUNLOP WORKS, CAR 63. WHEN REPLYING PLEASE QUOTE ON BOTH LETTER & ENVELOPE Research Department. ALL COMMUNICATIONS TO BE ADDRESSED TO THE FIRM Messrs. Rolls Royce, Ltd. Nightingale Road, DERBY. 24 August 1925. Dear Sirs, Attention of Mr.Robotham. HIGH SPEED STEERING WOBBLES. We think the conclusion drawn in the last paragraph of your letter of the 21st. instant is correct, and that the balloon tyres and wheels could not have been perfectly balanced. Whether this lack of balance is of the static kind, but too small to measure, or of the kinetic kind, is a point for further investigation. Although in your case, the period of the wobble is the same as the period of revolution of the wheels, we are not satisfied that this is a necessary condition. On another car, of similar type to your 40/50 model, we observed wobbles at several speeds, ranging from 58 to 70. It was possible to get through one critical speed, and to have a quiet interval before the next critical speed was attained. The idea of "conical precession without torque" was introduced to explain this phenomenon. | ||