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).
Technical memo discussing issues with shock dampers and suspension springs, and an initial review of competing Delco-Lovejoy dampers.
| Identifier | ExFiles\Box 16\4\ Scan256 | |
| Date | 23th February 1931 | |
| HS.{Lord Ernest Hives - Chair} DA.{Bernard Day - Chassis Design} FROM R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence.) C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} C. to E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} re. SHOCK DAMPERS. R2/M23. 2. 31. X7820 X. 235. X. 832. X. 7820. X. 5320. Under the conditions of bad roads we do not like the 10" deflection springs, and it will be noticed that not only do they bump badly on the buffers if fully loaded but the rebound will be so great that one feels that we must provide some limit by sling or otherwise, or we shall have even the 12" levers toggle. I do not for a moment hope or expect we can get increased damping unless we shorten the levers. The 13" shaft at present used must go down to 10" and the position of the shaft in a position more favourable to prevent toggling on rebound - i.e. anti-cipating rebound to be greater than bump. I believe these are wrongly ranged at present. Our square shaft is too small for long lever and heavy ball loads. I am sure we should get minute movements between lever and shaft that would ultimately fail (become really slack.) We all agree that it is of first importance for the springing to be stiffer for high speed (i.e. holding the road, steer-ing, etc) Secondly, if we cannot have stiffer springs we ought to have greater relief valve spring pressure on dampers, but that leak change would not really help us for difference between high speed and low speed, and that it is very undesirable to have this adjustable by chauffeur. I should like the car I use to have our middle stand-ard springing 9" rear - unless we can make considerable difference with dampers, because the 10" allows the car to dash about and roll at corners etc if the speed is at all high, and so tires the passengers and probably makes many feel sick, and I should very much like my car fitted up with 10" levers on the shock dampers after finding a better centre for damper shaft and suitable slings. The Delco-Lovejoy dampers are just to hand. (1) They are prohibitively heavy - i.e. if we made the whole car with the same disregard for weight it would be useless. There is no reason why we should not disregard weight in one part and not in another. (2) The main parts require to be put together by mandril or hydraulic press. This system is good but must be used with reason. In this case it would seem that one could not clean it unless the parts were taken apart at a big repairing works. It certainly seems a buy and throw away job, never clean or repair. (3) The double vertical one has not forced induction, but leaks and relief valve discharge into atmospheric chamber, as in their single acting type (probably designed before they examined ours.) (1) | ||