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).
Meeting minute concerning the testing and design of valve springs.
| Identifier | ExFiles\Box 80\3\ scan0108 | |
| Date | 17th January 1912 | |
| Ref. 111 (vii) Mr Swetnam. 17/1/12. TBB4/L17112. Copy of minute 7 of the 111th meeting of the T.E. Re Valve Springs. Mr Platford informed the Committee that he had tested 8 of the experimental springs having more coils and 4 standard springs, for a period of 209 hours continuous running at the equivalent speed of 60 m.p.h. He reported that 3 of the new springs had broken at 30, 32 and 108 hours respectively, and one of the standard type of spring had closed up slightly after 30 hours test; these springs had been replaced and no further failures had taken place. He was of the opinion that these springs were unsatisfactory and that something further should be done. Mr Barrington suggested that we should proceed with the suggested spring which was to have more metal in the coils by being made larger in the diameter of coils, and that these springs could then be tested beyond the stress which they received on the car, in order to discover any flaws. Mr Swetnam then submitted figures concerning a spring of this description for which he had previously received instructions. The stress with the valve shut, in this spring, was 40,000 lbs per square inch, with a load of 42 lbs, and with the valve open, the stress was 50,000 lbs per square inch, with a load of 51 lbs; the outside diameter of the spring had been increase | ||