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 the effects of axle pad width and shackle inclination on spring performance, referencing several graphs.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan159 | |
| Date | 27th May 1926 | |
| Contd. -3- Hs{Lord Ernest Hives - Chair}/Hml/T27.5.26. Graphs 3 & 4 shew that the wide axle pad, though it increases the rating of the spring a little over its entire range, does not affect the riding of the car to a measurable extent when the spring fitted is given the same initial deflection as obtains with a narrow pad. Briefly, pad variations within the limit used by R.R. have no effect on the springs other than to increase their torsional resistance. Graphs (1) & (2) shew that the vertical shackle will reduce the 21o shackle rating by 10% during the first 1" working deflection, the load to produce the same initial deflection being the same in each case. The effect of a vertical shackle increases with deflection. It would therefore appear that a vertical shackle is undesirable, because what is required is a spring with increasing rating as max. bump is approached, and a vertical shackle gives the reverse effect. To confirm the effect of shackle inclination, a third test was carried out with the shackle at 10o inwards in the statically loaded position. The results are shewn in Graph 10. In this case the shackle moves through the large angle (Graph 11) for big load applications and in doing so obviously increases the spring movement at the centre. We considered that this might alter the results and so corrected for it in Graphs 10 & 12; it will be observed that the alteration occasioned is not appreciable, however. | ||