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).
Future development of vehicle suspension systems, comparing leaf springs, torsion rods, coil springs, and rubber suspension.
| Identifier | ExFiles\Box 158\3\ scan0023 | |
| Date | 26th November 1939 guessed | |
| to Rm.{William Robotham - Chief Engineer} - 2 - hydraulic damping. Briefly then I think there will be a lot of development on passenger cars and commercial vehicles along the lines of using a smaller volume and weight of higher-quality material to replace the bulky, lowgrade leaf springs, which are both technically and economically unsound. A torsion rod has the maximum proportion of highly stressed material. It therefore is the most efficient spring, and responds most to the two manufacturing "tricks" of overstressing and shot blasting, neither of which has yet been adequately studied. Because of the feature of over stressing(adequately covered by recent articles in "Machine Design" by A.{Mr Adams} M.{Mr Moon / Mr Moore} Wahl) there is actually not the difference between torsion rods and coil springs of low index that was previously supposed. The coil spring therefore still ranks as an efficient suspension-means. Rubber suspension which is being tackled by Goodrich here has the dis-advantage that the creep of the rubber never really stops. An advantage is that rubber torsion bushings, if overloaded, take about three weeks instead of three seconds to break. Am emphasizing suspension in commercial and passenger design because it is obviously to the fore again, and does more than anything else to decide the shape and structure of the vehicle. Would like nothing better than three months to really acquire knowledge on this subject by a tour of the country, including Fageol on the West Coast. I would not waste any more time with leaf springs. The 1939 Buick and Olds are not quite right in rear suspension. The 1940 Olds is better. Our latest ideas on coil spring rear suspension are better yet. Will not take time to send them to you now, but they are well proved out. The point is that, in practical use, the worst we have done on coil spring rear suspension is better than the best we have done on leaf springs, because the suspension stays put. The commercial field has been made suspension-conscious by Fageol and my prediction is that in five years leaf springs will be nearly gone. Another development worth watching is the "White Horse", made by the White Company in Cleveland as a delivery van. This [handwritten: uses] the Franklin four cylinder-opposed air cooled aircraft engine as a power plant, all built into a torque tube construction for the rear axle. It is there-fore a rear-engine job in which there is no key mechanism at all in the vehicle itself. Franklin at Syracuse make the engine. We shall be seeing them before long. | ||