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).
Analysis of damper performance, focusing on the effects of oil temperature, vent size, and pressure phenomena.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan071 | |
| Date | 9th July 1928 guessed | |
| contd :- -3- is very clearly shewn in the four diagrams attached ranging from oil temps. of 19oC and 60oC (figs. 1 and 4.) If we enlarge the vent we expect the bump to go; it doesm but with loss of damper efficiency as will be seen in fig.5. If we put two large vents in series we get a better result (fig.6.) but we still lose a little at the beginning of the stroke. If we block the vent up altogether we expect that the pressure on neither the high or low pressure side will ever approach zero under working conditions. Figs. V1l and Vlll shew that this is the case. The whole phenomenon appears to occur only when the HIGH damper is over full with oil! Then when the low pressure valve closes there is more pressure in that end of the cyl; than in the rest of the damper, and when the low pressure valve opens the pressure in the two ends does not equalise out instantaneously. We have learnt a lot about the damper in these tests. For instance, we have been mislead by vents being partially choked; it is difficult to keep dirt out when frequently pulling the damper to pieces. Again, if either replenishing valve xx is not seating exactly we get the effect of an enlarged air vent. We did not realise the effect of temperature on the high pressure phenomenon to start with; no diagram means much on the standard damper xx unless the temperature at which it is taken is specified. In further diagrams of the standard damper which we attach (sheet 3) we have given the temperature at which the diagram is taken contd:- | ||