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).
Experiment investigating oil expansion and leakage in a component when heated.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan147 | |
| Date | 6th March 1926 guessed | |
| contd :- -2- filled it with oil at atmospheric temperature. We then placed a flat cap on the top (in place of the slightly domed cap at present fitted), carrying a thermometer and a fine bore copper pipe. The temperature of the oil was then raised 100°C by slowly warming the casing on a stove, and the oil lost through the tube was collected and measured - Prices Motorine 'C' being employed for the test. It was found that 35 c.c of the oil were lost through expansion. This figure was rather higher than we expected as it gives a co-efficient of expansion of 150 X 10⁻⁵ (about) for this oil whereas that of olive oil is only 80 X 10⁻⁵. This explains why on the uncooled bumping test oil is forced out of the gland. The small domed cap at present fitted only allows for 6.5 c.c expansion and the temperature of the shock absorber rises above 90°C, so that about 26 c.c. of oil has to escape somewhere. It also explains why the Houdaille and Berkshire shock absorbers leaked through their gland on the bumping rig unless they were kept perfectly cool. The working chamber had to be maintained choc-a-bloc with oil to prevent lost movement but no oil could get out except via the gland when its volume increased with temperature rise. contd :- [Text within diagram] TEMP RAISED 100°C LOSS OF OIL BY EXPANSION 35 CC's TOTAL OIL CAPACITY 300 CC's | ||