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 conducted on staggering the orifices in Phantom and 20 HP hydraulic dampers.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan066 | |
| Date | 30th March 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 RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c. to OY. ORIGINAL. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}1/LG30.3.28. PHANTOM AND 20 HP. HYDRAULIC DAMPERS. X235 8520 x 5520 With reference to R2/M9.2.28. We have conducted tests on the lines that you suggested of staggering the orifices. We attach the results of our tests. Owing to the present piston design there is no room to get staggered orifices in the low pressure passages, we therefore confined our tests on the low pressure side to seeing the maximum size of orifice that we could use to get the required pressure velocity increase. It will be seen that by making all the oil go through one passage it is possible to get the pressure increase with orifices .140" dia. instead of .083" dia. as previously used in Hs{Lord Ernest Hives - Chair}/Rml/LG8.2.28., and that the results so obtained are equally independent of temperature. It is clear from the figures of the high pressure side that if staggered ports were used the size of orifice could be made .200 or so, thereby eliminating danger of blockage by foreign matter. On the high pressure side we were limited to your first suggestion, as we could only open the passage out to .500 and therefore if we drilled two large orifices side by side there was insufficient restriction left. It will be seen that we can very easily obtain the required pressure rise, which is also satisfactorily independent of temperature, with orifices as large as .218" dia. These could contd :- | ||