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).
Modified Watford IS.12 magnetos for the Falcon X engine.
| Identifier | ExFiles\Box 43\4\ Scan056 | |
| Date | 25th January 1927 | |
| WC.1. 25.1.27. WATFORD IS.12 MAGNETOS FOR FALCON X. We have now received back from Messrs. Norths, magnetos Nos. 83119/20 which we returned for modification. They appear to differ from the magnetos we have at present in the following details:- (1) Distributor made of rubber base material, provision being made for radial connections, the H.T. leads being pierced by screws as on the B.T.H. (2) Condenser more protected than previously. (3) Cast iron distributor gear wheel. With regard to the above, the distributor is of good design and we consider it to be superior now to the B.T.H. in the following details:- (a) It is not cut away considerably to accommodate the contact breaker housing thus making it less susceptible to contraction without the addition of a thick dome. (b) In spite of not being cut away it is 3 ozs. lighter. (c) It has a better finish. Consider, however, that the provision of three extra ventilating windows in the head is unnecessary unless Messrs. Norths are in future discontinuing the fitting of two ventilation windows in the aluminium casting. The weight of these magnetos is slightly less, i.e. 14.9 lbs. We would suggest that the distributor holding down nuts should be made larger, they are rather small for the job and might easily get misplaced when fitting wires, etc. to the distributor. The H.T. safety gaps have apparently not yet been increased as requested, as they are only 7.5 mm. on these magnetos, though we have been given to understand that they are arranging to do this in future magnetos. These magnetos have been production tested on the bench to our own specification; No.83120 passed O.K. but No.83119 did not quite comply on the low speed sparking. EFC/H.E.West. | ||