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).
Analysis of shock damper loading, discussing the effects of axle velocity, oil flow dynamics, and viscosity.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 152 | |
| Date | 1st April 1927 guessed | |
| contd :- -5- exceptional working conditions should not exceed 10% of the total stroke. Actually the small increase in lost movement with increasing speed is far more than compensated for by the increase in load due to the high velocity of the oil through the passages. Within the range of working temperatures likely to be encountered on the road the variation in the behaviour of the damper may be said to be negligible. (E) INCREASE IN SHOCK DAMPER LOADING WITH INCREASE IN AXLE VELOCITY. Graphs 1. and 1V shew the way in which the ball pin loading of the high pressure side of the shock damper actually varies with axle velocity. With a normal high pressure loading of 30 lbs. the ball end load may rise to over 300 lbs. negotiating a humped back bridge at speed. Graph 1V. shews the difference between the high and low pressure ends of the damper with regard to their variation with increasing axle velocity. It will be observed that the low pressure loading does not increase very greatly with piston speed. The high pressure, however, increases very nearly as the square of the piston speed. We attribute this to the fact that the low pressure oil has only to pass through the piston, whereas the high pressure has to negotiate somewhat complicated passages in the casing with two sharp bends. Therefore the former obeys the law of streamline flow, the latter of turbulent flow. We anticipated that this increase in load due to oil viscosity would vary widely with the oil contd :- | ||