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).
Road tests to determine shock damper working temperatures and gland efficiency tests to prevent oil leakage.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan148 | |
| Date | 6th March 1926 guessed | |
| contd :- -3- The next series of tests were carried out on the road to determine what working temperature the shock dampers are likely to attain. We find that on a bad English road the dampers take up a temperature between 5°C and 10°C above the atmosphere. On a bad Continental road it is possible they would be between 10°C and 15°C above the atmosphere. Atmospheric temperatures in the south of France reach 35°C. Therefore in exceptional circumstances the temperature of the oil may reach 35°C + 15°C = 50°C. The dampers are filled with oil in the shop at about 15°C. Therefore the maximum rise in temperature the oil is likely to experience is 35°C. From our previous test this means that a space for expansion of 12 c.c. must be left in the shock absorber to ensure that no leakage takes place through the gland or breather provided. Gland efficiency tests. We have proved that even when the oil is given plenty of room for expansion the present gland is liable to leak under quite normal conditions. We ran a shock damper with an oil level at the bottom of the gland only, on a bad road with an atmospheric temperature of 5°C. After seven miles a leak commenced. It is clear that a breather is necessary because whenever the temperature of the shock damper raises under working conditions both the oil and the air expand and a positive pressure is built up unless there is an air vent somewhere. We have arranged a gland test - to get a figure of merit for any packing with rapidity - on the following lines. Pressure is supplied to a shock damper casing and a plain shaft rotated in the gland. contd :- | ||