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).
Rear leaf spring design, bump testing, and the use of Ferodo interleaving material to prevent squeaking.
| Identifier | ExFiles\Box 80\2\ scan0187 | |
| Date | 31th July 1920 | |
| Contd. -2- Hsl/LG31.7.20. regards absence of squeaking from the leaves. The disadvantage in the pre-war springs is increased weight. We do not feel happy with any rear springs which last less than 20 hours on the bump test because our present front springs average life is just above 20 hours and we know that we have not much in hand with regard to front springs because in countries like America we have a number break. X.4056. We have received now from Messrs. Woodheads some of the latest design rear springs with thin leaves. We shall be testing these shortly. X.3483. As regards Ferodo material for fitting between the leaves and the springs, although we have not yet received any satisfactory material from the ferodo people they are doing quite a lot of work with this and have submitted various samples. The best material which we have received up-to-date is the Ferodo material with a cotton base impregnated with graphite. We think that it is time decision was made on rear springs. We do not feel confident in recommending the modified springs of the present type. 1. because they do not overcome squeaking. 2. because the tests on the bump rig show them to be weak. We feel that we ought to get back to the pre-war type of spring. Perhaps we might modify the ends of the leaves so that they would be suitable for inter-leaving material. We think we ought to standardise the pre-war type of spring but of rourse still carry on our experimentst. We do not like the Contd. | ||