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).
Conclusion document outlining six key points regarding spring design and performance.
| Identifier | ExFiles\Box 56\2\ Scan070 | |
| Date | 23th February 1929 guessed | |
| (7) CONCLUSION. This subject might profitably be pursued further both mathematically and experimentally to more definite conclusions. For example, we cannot explain the difference in behaviour between springs No.(3) and (4) on SS.{S. Smith} unless there is more damping in the single spring, or a change of period consequent on deflection with the end coils closing up. In the meantime we set out the following points as they appear to influence spring design:- (1)...... It is concluded that high natural frequency/vibration is desirable. This is attainable with the same amount of steel by making the spring of greater length and smaller diameter. (2)...... It is obviously desirable to aim at a high figure of merit for stress. (3)...... Taper springs appear both in practice and theory to be better than parallel ones. They relieve the stress on the end of the spring that receives the initial impulse, and appear less subject to surging. (4)...... In double springs sufficient difference should be arranged between the natural frequencies of the inner and outer springs. (5)...... When there is insufficient room in the centre of the spring, as when a gland on the valve spindle is employed, it is better to use a single spring to restrict the diameter. (6)...... It is apparently preferable for the cam form to have a timing involving the largest indivisible factors possible. We are now engaged in reviewing the taper springs we had calculated for SS.{S. Smith} E.{Mr Elliott - Chief Engineer} | ||