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).
Recession of the control sylphon, dampers, and potential improvements to valve lift.
| Identifier | ExFiles\Box 151\2\ scan0036 | |
| Date | 18th March 1933 | |
| X235. HS {Lord Ernest Hives - Chair} /RM. {William Robotham - Chief Engineer} FROM HDY. {William Hardy} HDY {William Hardy} 1/M18.3.33. C. to SG. {Arthur F. Sidgreaves - MD} WOR. {Arthur Wormald - General Works Manager} E. {Mr Elliott - Chief Engineer} DA. {Bernard Day - Chassis Design} BY. {R.W. Bailey - Chief Engineer} DAMPERS. RECESSION OF CONTROL SYLPHON. It appears to us that from the point of view of recession of the sylphon alone the simplest way to effect an improvement is to reduce the valve lift. We think that it would be useful to determine what increase of valve angle we can make above the present 28° before we get valve vibration, also the effect of the reduced velocity-pressure. characteristic of the valve, and we send herewith N. sch. 3671. shewing 2 suggestions - A. {Mr Adams} reducing the lift to 70%, and B. to 50%, for the same oil velocity through the valve. Our impression is that we went straight from a parallel valve end to the present 28° taper without trying any intermediate angles. 2 It occurs to us that the recession trouble on maximum movements, such as on hump back bridges, is probably only of importance on the rear dampers where the restrictions of space endwise are much less severe than on the front. We can consequently use the special valve which we shewed you on the rear dampers if it should prove more stable, and therefore not require so much lift for damping. The reduced lift reduces the recession trouble. We send herewith N.sch.3670. which shews this valve, and we think it worth a trial. The valve springs of reduced rating are suggested to enable their effect to be determined, although with them the sylphon tube as shewn will have insufficient range of course. LAG IN CONTROL. We should like to know how the lag, when pressure is released, compares with the lag when increasing the pressure. So far we think we have only had figures for increasing pressures. HDY. {William Hardy} | ||