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).
Responding to queries on the testing of hydraulic shock absorbers.
| Identifier | ExFiles\Box 28\1\ Scan129 | |
| Date | 17th July 1928 | |
| Y832 To OY; from Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}; c: to Na{Mr Nadin}; Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LC17:7:28. HYDRAULIC SHOCK ABSORBERS. Y235 Replying to OY2/R6.28.28 - taking your queries in order :- (1) You will see from our further report that back pressure during the high pressure stroke depends on the size of the air vent and the temperature of the oil. However, we have satisfied ourselves that loadings in the ratio of about 8 up to 10 down give good results. For speed fiends and people who want a controllable car before a soft riding car, we recommend equal loading both ways. (2) You will observe from our report on the American damper which immediately follows this, that the pop-valve is not entirely absent even with slotted valve. As yet we are not sure what this is worth in terms of uncomfortable riding. (3) As you will see from our report, leaking valves of the dimensions you are using have very little effect at high axle velocities. Until we have obtained some figures for our axle movements we cannot really test these leaking valves intelligently. We shall get some road tests in the immediate future. (4) We will try some valves with narrower seatings. (5) See our report on slotted valves. (6) We agree we are probably testing shock absorbers at far too high a speed. With the standard shock absorber all that we require is information that the shock absorber is not going to go out of commission when subjected to the most strenuous working conditions. From our three tests we were able to get an indication of the way in which the shock absorber was behaving and so predict what it would do under any intermediate conditions. All the tests were supplemented by a slow running test which was only equal to 40 cycles per min. The set of 4 covered most conditions. We agree that before we can intelligently test your leaking valves we must do some road tests. (7) You will see that we have tested shock absorbers with your settings and leaking valves. contd :- | ||