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 design and stress testing of experimental valve springs.
| Identifier | ExFiles\Box 80\3\ scan0089 | |
| Date | 22th December 1911 | |
| Ref. 103(ii) Copy of minute 2 of the 103 rd Meeting of the T.C. Mr Swetnam 22/12/11 TBB3/L221211. Valve Springs (Experimental) Mr Swetnam had previously submitted figures concerning the design of a new valve spring, which would give a minimum and maximum stress in the metal of 43,000 and 57,000 lbs per square inch respectively. Mr Swetnam had based his design on measurements from a spring obtained from the shops, which he had believed to be a standard one. The springs when delivered to this design had proved to be incorrect and giving too great a load when fully compressed. The Committee had recommended that the spring should be made from wire of the same diameter as our standard, but having an extra coil to be accommodated by a stepped washer. Such a spring they understood from Mr Swetnam would have a maximum stress of about 57,000 lbs per square inch. The Committee agreed that further and more particular information should be given to Mr Swetnam as follows, in order that he might go further into the matter and obtain a spring of lower maximum stress. (1) The diameter of wire used to be the same as that of the springs at present fitted as standard; this figure to be obtained by actual measurement | ||