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).
Tests to determine the effect of temperature rise on the behaviour of hydraulic shock absorbers.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan039 | |
| Date | 1st 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. HYDRAULIC SHOCK ABSORBERS. X235 4443 We have conducted tests to determine the effect of temperature rise on the behaviour of the hydraulic dampers. It will be recollected that previously without the indicator we have only been able to read maximum pressures under temperature variation. Fig.1 and 2, shew the standard RR. rear hydraulic damper run at temperatures of 20°C and 60°C with compressor oil. We also took a test with Prices Motorine 'C' at 15°C - the viscosity of this oil at this temperature being about equal to that of compressor oil at zero. The tests were run at a 11" stroke to emphasise the temperature effect, actually at more normal strokes of 6" or thereabouts the temperature effect is considerably less than half that shewn on these diagrams due to the decreased pressure velocity rise. It is clear from figs. 1 and 2 that the standard damper for all reasonable air temperatures and working conditions gives consistent results. Actually fig.1. is equivalent to ats. temps. from -10° to +50°C and the variation from the mean damping is only ± 10%. Of course, in the standard damper the pressure velocity factor is not high and so we do not really expect much variation with pressure. There is no sign whatever of loss of damping through oil frothing suspected by Springfield, nor of the replenishment valves in the base being inadequate as lost movement is negligible contd :- | ||