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).
Proposed alterations to a T.W. spring design based on test results to improve durability and reduce friction.
| Identifier | ExFiles\Box 154a\2\ scan0358 | |
| Date | 1st July 1941 | |
| -3- Rm{William Robotham - Chief Engineer}/GB.1/RH.{R. Hollingworth}1.7.41. it is proposed to make the following alterations before proceeding with the second T.W. spring. 1. The stroke will be reduced from 7.5" to 5.5" to avoid overheating of the Harris bush in the shackle. This ran much hotter than the bush at the other end of the spring, although the angular movement was not much greater. The Harris bush heated up too quickly to allow the rig to be run for more than a 1000 cycles at a time at its running speed of 230 r.p.m. As a result of the shorter stroke, we shall expect 2.2 times the life. 2. The bottom leaf in the spring will be removed. Almost the whole of the tapered portions of this leaf rest on the lower rubber insulator pad. This facilitates reverse bending of the middle portion of the spring. The removal of this leaf should stop breakages at the centre bolt. 3. Buttons in high class rubber will be put in the ends of the interleaving. The primary object of this is to see if spring friction can be reduced permanently. In the spring just broken friction-loop depth was 40 lb at the start. After 12,000 cycles it had increased to 62 lb. The interleaving was in fair condition at the end of the test. The rubber buttons will give the inter-leaving a better chance of lasting a reasonable time on the road. Rm{William Robotham - Chief Engineer}/GB. G.B. | ||