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).
Issues and calculations related to vehicle rear springing.
| Identifier | ExFiles\Box 67a\1\ scan0048 | |
| Date | 31th December 1925 | |
| X8410 B.J. C. OWB. C. H?. C. Hs.{Lord Ernest Hives - Chair} BYll/H.{Arthur M. Hanbury - Head Complaints} 31.12.25. ***************** REAR SPRINGING. *************** Referring to BJS/H.17.12.25. and CWB1/EP.{G. Eric Platford - Chief Quality Engineer}11.12.251 I regret delay in replying, but have had a great deal of other technical issues to deal with at the Works. 1. In the first place, no change has been made in the method of springing during the whole of the post-war program, and therefore the suggestion that springs have got progressively stronger is impossible. 2. The inference made under (3) in CWB1/EP.{G. Eric Platford - Chief Quality Engineer}11.12.25. is that we supplied springs which were weaker than our formula normally specified. This is incorrect. The replacement springs were calculated in precisely the same manner as the originals, the difference in result was due to the fact that replacement springs were calculated from measured weights, whereas the original springs were calculated from estimated weights from coachbuilders, which were very seriously inaccurate, often both as to weight of body and passengers to be carried. When original estimated weights were accurate, no complaints arose. 3. The fact that we have had no complaints of weak springing is due to the point elaborated under heading 2, e.g. the new springs were not weak in relation to the load actually imposed. The original springs were strong by formula to loads actually imposed but were correct for loads originally specified. 4. If we have only changed fourteen sets of springs on all Phantoms delivered, we are within 5% of meeting conditions, and this represents a remarkably good performance. 5. If we were to weaken rear springs 250 lbs. each for accurately estimated loads, then the stress would be put up nearly 15% as an average. In addition, we would have to increase the free camber in order to maintain the axle clearance, which would in turn result in an increased range of stress. Contd. | ||