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 Ferodo Ltd. discussing time recording methods and sending them ignition components.
| Identifier | ExFiles\Box 141\2\ scan0310 | |
| Date | 14th July 1939 | |
| 1180 Experimental Dept. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}4/MH.{M. Huckerby} 14th. July, 1939. Messrs. Ferodo Ltd., CHAPEL-EN-LE-FRITH. For the attention of W.E.Shilton, Esq. Dear Sirs, We are sending you in a separate package F.O.C. a 12-volt ignition coil and a contact breaker unit. Both of these units have been used before but are in good condition, and we hope they will be of use. We do not advise using electric sparks for time recording although we have used this system ourselves, and can say definitely that it works. We consider that an ink recording is far superior as the record is immediately legible. Although electric spark, stylus on celluloid or stylus on waxed paper may each seem very attractive in particular circumstances, we find that once the novelty has worn off they become a nuisance, and valuable time is lost in interpreting the records. Spark recording suffers also from the disadvantage that most paper contains small pinholes and these can occur in misleading positions. We have recorded time by ink on paper on an apparatus in which the pen was moved by a magnet similar to that of a car cut-out, the coil being connected through a resistance direct to 50~ mains. The pen sometimes recorded 1/50 secs., sometimes 1/100 secs. according to spring tension. We did this to calibrate our 1/10 second clock. we can say that there would be no difficulty in recording 1/25 seconds by this means, using a synchronous motor and 1/25 second contact breaker or commutator segments, and this is the system we would recommend. However, if you wish to use spark recording we will give you any further help we can. | ||