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).
Adjustment of magneto timing, proposing a new scheme with a four-jaw driving drum.
| Identifier | ExFiles\Box 37\4\ scan 010 | |
| Date | 21th June 1917 | |
| X3091 F.{Mr Friese} H.{Arthur M. Hanbury - Head Complaints} ROYCE. COPY. c.c. to EH. EP{G. Eric Platford - Chief Quality Engineer}1/F25617. RE - ADJUSTMENT OF MAGNETO TIMING. Thanks for yours E4/B21.6.17. I am glad you appreciate the difficulty, which is not that we cannot get sufficient range of adjustment; the means of obtaining this are not sufficiently convenient for all practical purposes. I certainly think we ought to avoid any interference with the fixing of the drum of the magneto on to the spindle, and to obtain our adjustment by means of the internal keys on the end of the intermediate shaft, and the four position driving drum as suggested in your memo. I take it, therefore, that according to your memo it is our intention to avoid the serrations on the magneto drum, fix 25 serrations on the end of the magneto drive shaft (now 24 on the latest scheme), and a four-jaw driving drum. I think this scheme will be excellent, and suggest it should be adopted as soon as ever possible on all types of engines. The range of 2° which we should obtain would be quite enough. In pointing out that 5° was sufficient, what I should have said was that with the present engines the range of advance from 30° to 35° did not make any noticeable difference to the running of the engine when in service, but with the new type engine (the higher speed) the same applied between 35 to 40°. One can run at 40° quite satisfactorily without any falling off in power. The chief advantage of the later timing, however, is slow running. R.R. 255A (400) (T.S.) C.SC. 15-8-16 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1846 | ||