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).
Modification of a Crosby steam engine indicator to measure hydraulic shock absorber pressures.
| Identifier | ExFiles\Box 52\1\ Scan010 | |
| Date | 18th June 1928 | |
| To R. {Sir Henry Royce} from hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} c. to BJ. Wor. {Arthur Wormald - General Works Manager} c. to E. {Mr Elliott - Chief Engineer} DA. {Bernard Day - Chassis Design} c. to OY. BY. {R.W. Bailey - Chief Engineer} c. to Na. {Mr Nadin} +C4443 Hs {Lord Ernest Hives - Chair} /Rm {William Robotham - Chief Engineer} 2/LG18.6.28. HYDRAULIC SHOCK ABSORBERS. +235 for prints We have modified an old Crosby steam engine indicator to make it useful for indicating the shock absorber pressures. We use a very small piston in the indicator with a very short stroke, therefore practically no lost movement is caused by displacing the oil when the indicator piston moves - actually 15 thous. main piston movement is lost producing a diagram 1.00" high. We have special precautions for eliminating air from the indicator system, this at first gave us some trouble. We also experimented with different lengths of connection to the indicator to avoid pulsations. We now believe we are getting reasonable pictures of what happens in the shock absorber under working conditions. Attached are comparisons between the standard shock absorber and the pressure velocity type fitted to the rear of 14-EX. The most puzzling feature of the standard diagram is the way that pressure remains on the high pressure side during the low pressure stroke. We have tried a number of standard dampers - they are all the same. We have tried a good many things to eliminate it but we cannot, except by putting restrictions in the low pressure passages as will be seen from the velocity damper diagrams. All we can say is that it is nothing to do with the way the valves close, possibly it is the K.e. of contd :- | ||