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).
Test report on road springs and a traverse lean axle conducted on rough roads around Paris.
| Identifier | ExFiles\Box 82\2\ scan0166 | |
| Date | 15th August 1934 | |
| x4553 a Hotel de France, Chateauroux, Indre. France. To HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} From G.W.H. c. to RM.{William Robotham - Chief Engineer} 4 B IV. 15th August 1934. We have spent the weekend on the rough roads round Paris, testing out the 4° traverse axle and the front road springs sent out. We changed the road springs at the Depôt. We got SR. to try the car and give his opinion; the results are as follows: ROAD SPRINGS WITH INITIAL CAMBER 2.93. LOADED CAMBER .125. The springs give an approximate 20% softer ride over smooth pavé, and on rough roads no difference can be felt or noticed in the riding of the car. At high speeds on good roads the only difference one notices is a tendency to start bouncing, and requires slightly more damping. With regard to steering there is no appreciable difference with these road springs fitted. A much lower rating spring with more initial camber is required to obtain the results desired. With this combination, the damper loads would have to increase more rapidly to obtain control. With the present design, the soft riding could not be successfully obtained without seriously affecting the steering, and to really tackle the job satisfactorily, radious rods are needed to stop the wind up of the springs. AXLE. SR. was as delighted and thoroughly in agreement with us with the stability and steadiness of the steering with the 4° traverse lean axle fitted. There is no question of "if's" or "but's"; it is decidedly better and in SR's. opinion, no heavier cornering or on bad cambered roads. We intended to try the axle on the Paris trials car, but could not get hold of it for the time needed to do the change over, due to trial runs being in demand. The trials car would have been an exceptionally good test, as the steering on that car was very indifferent and very unstable on the rough roads, however we did our best. The results of our tests are therefore - road springs: The ones sent out FB.235 could be used with no ill effects, and would give a slightly softer riding. Axle 4° traverse - to be fitted, without modifications are carried out on the present axle, the reason being as follows: I tried the Paris trials car, and the report on B-88-AH, Monsieur Jules DELACROIX, Terlement, fully describes the steering as I found it when going over pavé. It can be cured immediately, but not the wing movement. No road springs will cure it. | ||