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).
Continued discussion on engine timing, spark advance, and preventing backward running in an engine.
| Identifier | ExFiles\Box 37\1\ scan 040 | |
| Date | 22th July 1918 | |
| R.R. & A (400 T) (S.C. 598 15-2-16) G 1545. -4- EPC10/T22.7.18. Contd. running backwards) to the contact point belonging to a normally later cylinder, but to an earlier cylinder running backwards, in which case, the spark would find the piston well down the stroke, and would certainly cause backward running if the conditions were right as regards mixture. Presumably, this state of affairs would be overcome in the A case by making the length of the periphery of the revolving arm, one half instead of one-third of the pitch of the stationary contact, as suggested in your R6/G12618. In the B case we have the impression that the metal segments are usually longer than one third of the pitch, and therefore, running backward, perhaps could not occur at full retard. (1) (m) Some intermediate position of the advance and retard lever seems to be the safest as regards prevention of back running because (b) would be insured against, and the spark for backward running, would be considerably earlier than in condition (a). (2) (a) If we assume again as we did for (1) (a) that the spark takes place A.{Mr Adams} When the leading point of the periphery of the revolving finger is exactly opposite a stationary contact point. B. When the brush has just commenced contact with a metal segment. (This, of course, will now remain the same for all positions of the advance lever) then the possibility of backward running is the same as for (1) (a). Contd. | ||