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).
Brief summary of development work on the new J.III type hydraulic shock dampers, covering silence, riding comfort, and oil loss.
| Identifier | ExFiles\Box 179b\3\ img396 | |
| Date | 29th March 1933 | |
| To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. By.{R.W. Bailey - Chief Engineer} By.{R.W. Bailey - Chief Engineer} c. DA.{Bernard Day - Chassis Design} Hdy.{William Hardy} X235 NEW TYPE HYDRAULIC SHOCK DAMPERS. The following is a brief summary of the development work so far carried out on the J.III. type dampers. DAMPER WITH FIXED LOAD. Silence. The original trouble experienced was noise from the valve. This was overcome by using a relatively small valve with a long taper seat to give it a high lift, and damping the movement of the valve by means of a large disc working with a small clearance in a cylinder. It was proved that the valve could be silenced in this manner, and we have had no complaint of noise on the three cars which have run in France with this type of valve. Riding Comfort. The small diameter of the valve coupled with the length of its seat causes the effective ball pin load to increase considerably with speed, but this pressure velocity factor does not seem to be a material disadvantage with regard to riding comfort and car control up to the present. We believe we can satisfy customers with the fixed load J.III. type damper to the same extent that we are satisfying them with the existing standard shock damper. Freedom from loss of oil. We have had various types of gland on the new shock damper. We have not, however, found one materially cheaper and more reliable than our existing standard spring loaded asbestos gland. The last Peregrine has two dampers fitted with glands in which oil resisting rubber was used to load the asbestos instead of a spring, and these did not leak appreciably during the test. However, there is no doubt that the spring will have a better life and be more reliable than the rubber, to which you have already expressed an objection, and we are therefore reverting to our present proved product. | ||