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 performance and testing of three types of hydraulic shock absorbers.
| Identifier | ExFiles\Box 29\1\ Scan083 | |
| Date | 26th September 1925 | |
| X 457 EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG26.9.25. To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to CJ. BJ. 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 Wcr. HYDRAULIC SHOCK ABSORBERS. X8520 X457 We have tested three types of hydraulic shock absorbers - these are - Derihon. Houdaille. Berkshire. The tests consisted of adjusting the shock absorbers to three-quarters their max, loading and running them at a speed equivalent to 30 m.p.h. on a chassis on the bump rig. We also tested the Berkshire shock absorbers for 400 miles on ordinary main roads. We found that in every case, oil leaked badly from the glands after a few minutes running. As soon as the shock absorbers became hot, their efficiency decreased enormously. The oil leaked on the Derihon so much that after 2 hrs. running one shock absorber was entirely out of action, the other was very feeble. The Houdaille were perhaps the best of the three types tested but they leaked oil copiously and one lost 90% of its efficiency after 1 hrs. running. The Berkshires were covered with oil which exuded from the gland after a 400 miles road test. On the bumping rig however they did not lose so much oil as the Derihon, and when allowed to cool down after the test, recovered some of their original efficiency. They both developed a certain amount of lost movement however possibly due to air contd :- | ||