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).
The effects of oil viscosity and temperature on shock absorber pressure, using staggered orifices.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan067 | |
| Date | 30th March 1928 guessed | |
| contd :- -2- be made still larger if more of them were employed, but we can see no advantage as they are far too large to get blocked up. The following table (obtained with Prices Motorine 'C', as with this we can reproduce the effect of zero weather on compressor oil), shews that the pressure obtained in the shock absorber, and hence the effective loading only drops 8% when changing from oil having a viscosity of 3500 secs. to one of 60 secs., equivalent to running the damper filled with compressor oil in ats. temps. varying from -10°C to +50°C. This demonstrates that with the staggered passages the energy loss is almost entirely kinetic. We have attached the tests by which we arrived at the required arrangement in full as we thought they might be of interest. Staggered orifices arranged as in 7H. Prices Motorine 'C'. Piston vel. 14"/sec. Table Data: Column 1: Oil viscosity Redwood secs. Column 2: Oil temp. °C. Column 3: Pressure lbs/sq. in. Row 1: 3500, 15, 825 Row 2: 2000, 20, 800 Row 3: 600, 40, 775 Row 4: 200, 60, 775 Row 5: 100, 80, 775 Row 6: 60, 100, 760 We have therefore established that staggered orifices to your sketch enable the required pressure rise to be obtained with good large passages, and that the pressure rise so obtained is practically independent of temp. within the normal limits of atmosphere in this country. We have taken 800 lbs/sq in | ||