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 performance, valve characteristics, and road test findings.
Identifier | ExFiles\Box 28\1\ Scan192 | |
Date | 30th January 1931 | |
-2- Taking into consideration the simplicity of the adjustment it cannot be said that the whole result is unsatisfactory, in fact they appear to have attained a very good compromise. Loadings. The poundages given with this damper with the largest leak(No. 4) are some 50 - 75 lbs higher than those of the standard rear damper that is, tried on a car in America and diagrams of which are given in Ha/Hm.{Capt. W. Hallam - Head Repairs} 2/W.30.1.31. Actually the dampers are fitted up as Delcos' think they should be to control an R.R. car and yet give soft riding and not to R.R. of America's specifications. Valve Silence. We note that the valve guides are set eccentric with the valve seats (sheet 4.) We conclude that this must be another feature introduced to produce silence, so far of course, valve noise has not been one of our troubles. Road Tests. Preliminary road tests show that the car riding is altogether too hard at the rear with the smallest leak for anything but speed work. Even with the largest leak we think that the riding is on the hard side though considering that the ball pin loads must approach 200 lbs. at the maximum on the rebound this is hardly remarkable. The dampers control the car well and there is not much tendency to roll whilst its behaviour over obstacles such as level-crossings is commendably good. It is clear that under these conditions, the pressure velocity increase in load is an asset, it takes the jerk out of the back seats. The car was, of course, tested with the new standard spring deflection which is 4.5" front, and 10.25" rear. We know that we can use much higher compression loads than they do without causing hard riding and shall therefore try bringing the High and Low pressure damping nearer together which we have always found give the best results. There is no doubt that the Delco valve arrangement gives a good range of loads considering the simplicity of adjustment, and once the correct characteristic has been established, such an adjustment would be useful owing to the diversity of customer's requirements. Ha/Rm.{William Robotham - Chief Engineer} | ||