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).
Improvements and considerations for the vehicle's spring and suspension system.
| Identifier | ExFiles\Box 72\3\ scan0118 | |
| Date | 10th September 1924 guessed | |
| contd :- -2- I do not know why we require 4 clips per spring but I think they can do no harm. To lessen the stress on the bump and generally make the spring safer I suggest we increase the thickness of the rubber buffer. We should not anticipate any ill result from doing so (in fact, the rubber buffer could nearly fill the space). This will be included on the new drawing. Regarding the failure of the central bolt you will remember that I mentioned that this happened though had fitting on the 20 HP. in exactly the same way, and was the reason for fitting blind ended caps so that the bolt could not escape. At the same time we may consider it desirable to slightly increase the size of the central bolt. ++ No car should be sent out either for experimental or trials purposes, or to customers, unless it has the uniform standard pattern of clip and as the one fitting the square keys on the axle is superior, and can be inspected, this pattern should be adopted at once. Whether the top plate is .3125" or .285" I cannot but think it is advisable to run both in France, as the road test is the only really true criterion. DA.{Bernard Day - Chassis Design} points out that the slight increase in the length of the springs, even allowing for the longer encastrements on the axle, should give a spring of longer life unless other changes we have made, such as stresses due to braking, affects the life of the spring. Apparently the braking has very little affect, as the springs appear to be lasting better than the old 40/50 springs. In conclusion, I cannot say more than that I pray that we get on with the work, and I see no reason why we cannot get satisfactory springs with either 12½%, 20% or 25% increase in stiffness, and why we cannot go into production with front wheel brakes acting more mildly. If we had one stiffness of spring for the front axle then the fast open light cars would have stiffer springs and the heavier closed, slower cars more flexible springs. The variation of loadon the front axles only varies a little so that this might be quite good, inexpensive and practical. R.{Sir Henry Royce} ++ This is at present ⅜". I doubt if it would be better at 7/16". | ||