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).
Noisy magnetos, discussing modifications and tests with supplier Messrs. North.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan093 | |
| Date | 8th March 1928 | |
| -3- Contd. The two machines (No.100080/1) which were put on 14-EX and 15-EX for France were also reported noisy. Now in regard to magneto No.106012 which was reported in EFCS/T8.3.28 as having been fitted with the continuous cam ring. This machine has apparently continued to be reasonable in all respects, but is now on 16-EX in London. In regard to the point about the angular location of the distributor rotor, we have heard from Messrs. North that they will revert to the method of locating the rotor arm on the wheel by means of a brass plate milled to fit the arm. We have also heard from Messrs. North that they will be fitting continuous cam rings to the experimental machines that we had sent back to them as unsatisfactory, and they hope to let us have these very shortly. In regard to the source of the noise, Messrs.North remark - "We had formed the impression that the noise made by the contact breaker was in the closing of the points, but if this were so the form of cam housing could have no effect on it, and we found that even with a cam giving an extremely rapid closing of the points no difference could be detected in the amount of noise, with the continuous cam ring housed as it is in magneto No.106012 and we think you will find that the contact breaker as arranged in this magneto is as quiet as it is possible to make it." Our endurance test will also show up the endurance of the platinum points. We have suggested to Messrs. North the use of tungsten points as on the Lucas machine, and their answer runs as follows :- Contd. | ||