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 Cadillac describing their method and advantages for conducting torsional tests for frame stiffness.
| Identifier | ExFiles\Box 170\2\ img277 | |
| Date | 2nd July 1935 | |
| oy CADILLAC - LA{L. A. Archer} SALLE MOTOR CARS CADILLAC MOTOR CAR COMPANY DETROIT, MICHIGAN July 2, 1935. GRY{Shadwell Grylls} W. A.{Mr Adams} Robotham, Esq., Rolls-Royce, Limited, Derby, England. My dear Rm{William Robotham - Chief Engineer}: Think I will send you enclosed two pictures of torsional tests for frame stiffness. The one with the channel-beam representing the rear spring, is the more up to date method. The three cardinal planes are: Plane of front wheels Plane of dash Plane of rear wheels Other planes are measured only to detect detail weaknesses. The measuring points on the cross bars are 57.3 inches apart, so that 1" difference in level is one degree of twist. The advantages of this method are:- (1) It can be applied equally well to bare frames or complete cars. (2) It assumes no axis of twist yet gives results in lbs feet per degree. (3) No heavy clamps are used on the frame. These change its stiffness entirely. (4) The frame is loaded almost exactly as it is loaded in practice. The light metal box has very soft rubber feet so that it is as nearly as possible like a heavy fog lying on the frame. | ||