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).
Damper and governor control tests, discussing load, oil viscosity, and valve performance with a table of results.
| Identifier | ExFiles\Box 179b\2\ img093 | |
| Date | 11th November 1932 | |
| -3- HS{Lord Ernest Hives - Chair}/Rs.{Sir Henry Royce's Secretary}4/A.11.11.32. Cont'd.{John DeLooze - Company Secretary} It appears that we should be able to increase our damping some three or four times with the speed of the car. The point which will be proved out by road test, is whether we can, with the somewhat small valve, get a soft enough ride at low speeds even with a 4 lb. minimum static load. (It seems to take about this load to push the valve off its seat even with the spring removed). It will be noted that at a 1" stroke, 540 frequency (Diagrams G.6 and G.10) the minimum ball pin load attained is 100 lb., and 80 L.P. is about the frequency of axle dither on the road, but whether it does this at very low speeds when an ultra soft load is required remains to be seen. We now have a car completely equipped with the latest type dampers and Governor control on the road. One feature, the reason for which we have not yet ascertained, is that the pressure produced by the governor at any given speed is not independent of the viscosity of the working fluid. Thus, using our normal shock damper oil, the figures given below indicate that the damper load will be about halved over a 20°C rise in oil temp. We attach a viscosity curve of this oil and one for normal brake fluid. AIR H.Q. 3418 J.111 TYPE SHOCK DAMPERS. VISCOSITY - PRESSURE TESTS. "COMPERISON" OIL. REPEAT TEST. LOAD ADJUSTED BY PRESSURE RELIEF AT GOVERNOR AND DAMPER. P.R. Fluctuating. | Road Speed M.P.H. | Governor Speed R.P.M. | 20°C Gov: Press | 20°C Damper Press | 40°C Gov: Press | 40°C Damper Press | 60°C Gov: Press | 60°C Damper Press | |---|---|---|---|---|---|---|---| | 30 | 126 | 3 lb/sq" | 3 lb/sq" | 2 1/2 lb/sq" | 1 1/2 lb/sq" | 1 lb/sq" | 0 lb/sq" | | 60 | 256 | 8 " | 8 " | 4 " | 4 " | 2 to 14 | 3 to 5 | | 80 | 342 | 11 " | 11 " | 5 " | 5 " | 5 to 22 | 9 to 13 | | ||