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).
Testing of shock absorbers, dampers, and oil viscosity for vehicle suspension.
Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan153 | |
Date | 26th May 1926 | |
Exml. Report (Contd) -2- Hs{Lord Ernest Hives - Chair}/TmL/T26.5.26. the friction shock absorber broke. Also by the condition of the spring stops the rebound was not so great with the R.R. dampers as with the Hartfords, in spite of the greater severity of test. We have been trying to account for this. We have rigged up an R.R. damper on the apparatus used to test the "LANCIA" damping. We find that with "Price's C" oil at 40°C (see viscosity curve) the resistance to oil flow through the high pressure valve port is 120 lbs/sq." for a flow of 1.75 galls/min. In other words, when the rear axle is moving downwards with a velocity of about 2 ft/sq. the force at the shock damper ball end opposing its motion is about 35 lbs.(even when no spring is fitted above the high pressure valve) due to the viscosity effect of the coil. We have made a rough calculation, that when the rear wheels of the car leave the ground for an appreciable period, as happened in the recent tests, the maximum velocity of the axle, if it was unrestrained would exceed 10 ft/sec. We may therefore say that the hydraulic dampers exercise a very powerful effect in restraining the axle during rapid movements and large deflections. This is probably why they are so very effective in dealing with high speed wobbles. We have been trying to find an oil which will enable us to use viscosity without introducing the danger of harsh riding in cold weather. Attached is a viscosity curve of the lubricant used in the "Lovejoy" shock Contd. | ||