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).
Steering wobble tests for chassis 93 NK under various road and tyre pressure conditions.
Identifier | ExFiles\Box 71\4\ scan0301 | |
Date | 13th July 1925 | |
48840 Hotel de France, Chateauroux. Indre. France. To: "HS{Lord Ernest Hives - Chair}" From: G.W.Hancock. Re Chassis 93 NK. Further tests with steering. Tyre pressures N.S. 25 lbs. O.S. 60 lbs. Wheels unbalanced 1/2 lb. approximately. Tests on smooth roads - the steering has a tendency to wobble at 63 and 68 m.p.h. The wobbles are not so definite as results obtained with tyre pressures reversed. There is, however, a distinct feeling of the steering being more unstable. The car is continually wandering at high speeds. On moderate roads, the conditions are slightly worse. The wobbles develope at 64, 66 and 68 m.p.h. On retard, we occasionally get a wobble at 63 m.p.h. We did get, once or twice, a severe wobble at 60 m.p.h., but it immediately died out. The results are dependant on how the wheels happen to strike the rough surfaces on the roads. We can travel the same piece of road time after time and not obtain a wobble. When going over again, the wobbles will suddenly develope up. At low speeds the steering is slightly lighter than with the tyre pressures reversed. The results given on all these tests are on an average run of 200 miles. All tests are carried out on exactly the same stretch of road, one portion of which is in what we would say a fairly good condition, and the other portion is on where the road is gradually breaking up. We have not, on any of these tests, got the severity of wobbles that was obtained in the first 15,000 miles test with the car. Please note that the springs in side steering tube are the old standard 40/50 HP. type, i.e. strong springs. We have got light springs, which we are at the present moment, trying. Reports on these will follow to-morrow. G.W.Hancock. | ||