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).
Letter to Messrs. North & Sons Ltd. concerning a comparative road test of experimental magneto cams.
| Identifier | ExFiles\Box 65\3\ scan0124 | |
| Date | 30th November 1927 | |
| X 7791 EFC5/T. 30th November, 1927. Messrs. North & Sons Ltd., Whippendell Road, WATFORD. Dear Sirs, We have now had an opportunity of making a comparative test on the road on the noisiness of the experimental magneto cams as compared with the standard, which experimental cams Mr. North brought with him for the purpose on his last visit. From the silence point of view we found the experimental cams noticeably progressively better for noise according to the slowness of the make. We do not understand why, in the experimental cams submitted, these have been arranged to give a short & period of break which means that with a given setting of the controls the magneto breaks contact late and makes early. What we should now like to have is a set of cams with the same degree of slowness of the make as the experimental cams which you labelled as being " 150 spindle movement, corresponding to .004" at the contacts" but to give the same timing of the make and break as the original cams on the machine when the gap is at its normal value. That is to say, it would not do merely to grind away the standard cams to produce a slower make because the required condition of the same average timing (for normal gap) would not thereby be met. The improvement is sufficient to render it well worth your while, in the opinion of the undersigned, to produce us as quickly as possible a pair of cams as described which can be fitted to this machine (No.99171). This might just produce sufficient difference to render this machine sufficiently good for us to put on our impending 10,000 mile test car, for which purpose you are very shortly going Contd. | ||