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).
Summary of test results for a shock damper valve, detailing various modifications and performance outcomes.
| Identifier | ExFiles\Box 105\3\ scan0255 | |
| Date | 4th July 1932 | |
| N.Sch.3405 SHOCK DAMPER. SUMMARY OF E.58789 VALVE TESTS. (FURTHER TO PREVIOUS REPORT OF 10.6.32.) The best results so far obtained are with Hs.{Lord Ernest Hives - Chair}651/1 type valves, (i.e. drilled, undercut, grooved, blanked, and .010" mask clearance.) The next modification of any importance consisted of a chamfered extension to the low pressure end of the valve (see Hs.{Lord Ernest Hives - Chair}657A), in addition to the above modifications, to act as a guide, and also to "unbalance" the valve. With this type of valve fitted to the dampers on J.III chassis set to give .005" initial lift (instead of .025" as standard), they were reasonably quiet, except for oil "hiss". Indicator diagrams however, showed that the L.P. damping up to 1 ft per axle velocity was weak, whilst the H.P. pressure increased with the speed. A valve was then made to give a longer guide (See Hs.{Lord Ernest Hives - Chair}651 Sheet II) the guide being unbalanced by slotting on one side. It was tested on the rig without the various leaks, but both squawk and knock were evident, the diagrams however were reasonably good. Whilst testing this valve it was found that, by stopping the H.P. feed to the bearings, the damper became quiet. Diagrams however, showed lack of air venting on the H.P. side - the pressure did not return to the atmospheric level. Even when the oil passage to the bearings was restricted to .055 and also to .025" diam the squawk and knock remained. | ||