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 effect of individual magneto timing on engine detonation.
| Identifier | ExFiles\Box 179\2\ img223 | |
| Date | 10th February 1932 | |
| ORIGINAL. R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/YAG. c. to SG.{Arthur F. Sidgreaves - MD} H.R. c. to MS. E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} c. to Mr.Jaques. x2965. Hs{Lord Ernest Hives - Chair}/Yag.1/HA.10. 2. 32. THE EFFECT OF INDIVIDUAL MAGNETO TIMING ON DETONATION. A scheme was bee drawn up to simplify the ignition wiring. The main feature of this scheme as far as the functioning of the engine is concerned is that neither of the individual magnetos will fire the inlet or the exhaust spark plugs singly, as with the existing scheme. This of course makes it imperative to time both magnetos to the same setting. The point was raised that if one magneto was advanced or retarded - as the case may be - on the other a reduction in the detonation intensity would result, and tests were carried out to investigate this. Conditions of Test. Engine Kestrel III - S - EXP. 2 (Std fully boosted (Kestrel with 8/1 UR.)) Fuel D.T.D. 134. Plugs Lodge A.2. Magnetos (A side SC 12-9 BTH. (Bside SC 12-7 Tests were carried out as follows :- The standard arrangement of inter-connected magneto and throttle controls was dispensed with and the magnetos fitted with independent controls. The engine was run up to a point where detonation was audible at a distance of 6 ft from the engine. The setting of both magnetos was then adjusted to give maximum power and the throttle reset to restore the detonation intensity to 6 feet. Each magneto was then moved independently throughout its advance and retard range. It was found in both instances i.e. by advancing or retarding either of the magnetos whilst keeping the other in the position for best power, that no change in the intensity of the detonation resulted, but rather a slight increase in the frequency of detonation occurred. | ||