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 Phantom Automatic Advance, discussing Watford magnetos, spring friction, and servo motor performance.
| Identifier | WestWitteringFiles\O\January1926-March1926\ Scan171 | |
| Date | 27th March 1926 | |
| TO HS.{Lord Ernest Hives - Chair} EFC.) FROM R.{Sir Henry Royce} (E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} ) (Le CanadelHenry Royce's French residence.) Copy to CJ. BJ. [STAMPED: ORIGINAL] PHANTOM AUTOMATIC ADVANCE. R1/M27.3.26. Rec'd at WW. evening of 31/3/26. X.8685 X8796 Regarding Watford magnetos I feel we ought to be extremely careful in changing to another make, and we ought to make the best of what has proved reliable and has really met our specification, and until commercial, or some other reason of value for money in equally good quality at a lower price forces us to change. (Lucas' have not - I believe - a good name for magnetos.) Working as I do away from the Exp. Dept. I cannot see any reason why the sleeve friction should be over 1 lb. and the other 2 lbs. should not be a retarding spring on the rocker arm of the magneto. 7-EX. is now so fitted up and the servo motor will return to zero without any other spring, so that as far as I can see the oil pressure need only be about one third the minimum stated in some recent notes. EFC. is I feel sure not correct when he says my spring on the magneto rocker will not do instead of the friction. Certainly I am convinced that at least a half can be spring if for some other reason a half should be friction. Again my spring is more lasting than the friction, and the return spring can at least be reduced to a quarter of its present strength. This will considerably reduce the required oil pressure and lag - (to about a quarter.) You will realise that you are not making the best of this apparatus, probably due to EFC's remarks. I find from HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} that we already arrange that the servo motor gives an advance as soon as the oil pressure is sufficiently independent of the governor: this should take care of the lag quite well so that there now seems little wrong with 7-EX. as I have it - RM.{William Robotham - Chief Engineer} knows my views. R.{Sir Henry Royce} | ||