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).
Road and bench testing of experimental magnetos, detailing performance variations and starting issues.
| Identifier | ExFiles\Box 65\3\ scan0386 | |
| Date | 20th July 1929 guessed | |
| -3- contd. "for road testing, and another No.118716 was fitted to a test bed engine for the purpose of obtaining power curves with the increased magneto advance. The remaining two magnetos were tested on the bench to our general schedule of experimental magneto performance. The results of these tests on each magneto have been duly recorded. "We found that the low speed sparking and the utility performance generally had been improved, but we also found a considerable variation in electrical performance fully advanced between the two magnetos. In one case, as will be seen from the figures, the fully advanced performance at high speeds was very poor and not, we consider, satisfactory; but in the other case it was quite satisfactory in fact very good. This variation may be due to the slight variation in the contact breaker timing, as the open circuit volt and short circuit ampere speed curves of each magneto were almost identical. The timing in the fully advanced position with such a large range would necessarily be very critical. "We have had an opportunity of trying one of these magnetos fitted to 22-EX. With the engine cold, battery ignition switched off, and the magneto fully retarded, the engine could be easily started using the starting handle. This was not possible, only in a few isolated instances, on the EW6 magnetos and Lucas ER6 magnetos, the electric starter being necessary to start on magneto fully retarded - cold. | ||