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).
Improvements in contact breaker springs, comparing them to a Delco-Remy design.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 71 | |
| Date | 24th December 1926 guessed | |
| -5- Contd. Apparently there was a slight improvement, these giving the best results in their respective classes, but the improvement may have been due to the increased mechanical contact pressure brought about by using the same spring with an increased set. Some light will be thrown on this when we have completed test No.13 on both tungsten and platinum, of increased mechanical contact pressure, other things being the same. It has been a bit difficult to obtain springs which will suitably do this as the stress for the present design of spring becomes rather great if we increase the set. The stress is also a bit greater if we utilise a spring of the same unstrained shapebut of thicker gauge, but not greater in the same proportion as the pressure on the points is increased. In regard to this matter of springs a point we have noted in the Delco-Remy contact breaker which apparently is not the case on our own, is that in the average working position the force between the cam and the rubbing block is nearly equal and opposite to the force applied by the fixed framework to the end of the spring in contact with it. This means that the spring is in approximate equilibrium (unstable) in the absence of the pivot, and that the actual thrust on the pivot is round about zero. That, we think, is not the case in our own contact breaker, and we feel it is desirable that it were so. Contd. | ||