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 performance of Lucas and Simms magnetos for the New Phantom.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan26 | |
| Date | 27th January 1926 | |
| Expl. Report. Exp. No:-8790. EFC4/T27.1.26. To R.{Sir Henry Royce} from EPC. c. CJ. E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} By.{R.W. Bailey - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} Rg.{Mr Rowledge} ORIGINAL Noted HS{Lord Ernest Hives - Chair} EXPERIMENTAL MAGNETOS FOR NEW PHANTOMCodename for PHANTOM I. Further to our EFC2/T5.1.26, bench observations on the electrical performance of Lucas and two Simms magnetos therein referred to have now been completed. Length of H.T. safety gap in all three machines 8.5 mm. Range in all three cases 60°, the figure representing our requirements being 58°. All these magnetos are non-sleeve machines. There is nothing abnormal about the timing of the make and break. In each case the cams are rather longer than 90°, giving a period of make less than .5. In this respect they differ considerably from our standard Watford which has short flat cams. In the Lucas case the cam is continuous, giving a gentler make and break, and we find this helps to reduce contact breaker noise considerably. This, however, is not so in the Simms case. The Simms cams are long, but not continuous. Electrically, on principle, we think cams should be long, giving a period of make not more than 100°. In our standard Watford magnetos the period of make is about 156°, and on first making, a reverse current may be generated; some of the positive volt impulse will be Contd. | ||