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).
The experimental use and cost analysis of tungsten points in chassis magnetos compared to standard platinum points.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan212 | |
| Date | 16th December 1929 | |
| EFC/AMS.16.12.29 contd. -5- in the general improvement of chassis magnetos, and we shall endeavour to get through the experimental stage as soon as possible of LW6A magnetos fitted with tungsten points. The condition and appearance of the tungsten points which have passed through our bench endurance test are certainly remarkable, whereas on standard magnetos on experimental cars the average life has not been much more than 6,000 miles. We are, as opportunity presents itself, changing the LW6A magnetos already on experimental cars for machines duly fitted with these tungsten points. It will be understood that Messrs. North, from the results presumably of tests previously made on magnetos with less efficient windings, have been, until lately, rather strongly opposed to the use of tungsten points, and that fact has made it rather difficult to get them to move in the matter in spite of the fact of this being more or less accepted standard practice with other manufacturers. Now that we have helped them to improve their windings they appear to be quite enthusiastic in the direction of the use of tungsten points, also suggested by ourselves. With regard to relative costs, Roy{Sir Henry Royce} has obtained for us information from Messrs. North to the effect that the extra cost per magneto with the larger iridio platinum points would be 3/- per magneto, whereas the less cost by the use of tungsten in place of the usual standard platinum would be 3/2d. per magneto. EFC. | ||