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).
Modifications to suspension shackles and seat cushions to improve vehicle ride quality.
| Identifier | ExFiles\Box 43\2\ Scan142 | |
| Date | 8th May 1928 | |
| Oy1-E-5826 -4- May 8th, 1928. II. (cont'd.{John DeLooze - Company Secretary}) d.{John DeLooze - Company Secretary} With these same front springs, standard pre-front-brake shackles were fitted at the rear end. The riding and steering are considered to be still further improved. We are unable to explain any improvement in riding from the single change from front to rear shackle. I therefore wrote to Mr. Hives, suggesting that we may have introduced an error here, because in making this change we put in the threaded shackles with loose-fitting steel bushes. These allow free rocking of the fpring on the shackle bolt. Since these almost cancel the torsional effect on the spring when one wheel rises, they may have an effect on the riding quality. It has been observed generally that on these threaded shackles where the shackles have a slack fit vertically the riding is improved. e.{Mr Elliott - Chief Engineer} Cushions. The latest step has been to remake the rear cushions and backs in accordance with our latest practice. Unfortunately, since we have no cushion testing device it is not possible to give figures for these. The principle however is to have sufficient down to give a soft surface, a considerable depth of curled-hair to give softness and damping, and light spiral springs entirely undamped to give as low a frequency of oscillation as possible without bottoming. The cushions are cloth and there is no air damping. The backs are made with exceedingly light springs at the shoulder level and stiffer springs at the waist level. The springs are only tied down sufficiently to hold them in place. These cushions not only improved the impression of riding at the rear very greatly, but, when transferred to a front-brake Silver Ghost on which there was complaint of riding, they gave a similar result in the latter car. Probably they would be criticised as somewhat unstable for travelling at speeds above 50 m.p.h. but such speeds are not common in the U.S. | ||