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).
Performance specification for a six-cylinder magneto with automatic advance for the BR. 40/50 car, version 2.
| Identifier | WestWitteringFiles\M\2October1924-December1924\ Scan84 | |
| Date | 20th October 1924 | |
| SPECIFICATION OF PERFORMANCE OF SIX-CYLINDER MAGNETO ( WITH AUTOMATIC ADVANCE ) FOR BR.{T. E. Bellringer - Repair Manager} 40/50 CAR. VERSION 2. (1) The weight of the magneto complete with automatic advance mechanism but otherwise without coupling, shall not exceed 15 lbs. (2) The length of the H.T. safety gap shall not be less than the equivalent of a sparking over voltage of 12000 steadily applied. This, in ordinary forms of safety gaps will correspond to certainly not less than 8.5 mm. and probably somewhat more. (3) The total available firing range in magneto degrees shall not be less than 60°. Of this, not less than 30°, and preferably as much as 35°, should be automatic advance, and the remainder hand advance. The automatic advance should commence at a magneto speed not greater than 600 r.p.m. and attain its maximum amount of 30 to 35° at a speed at a speed lying between 3000 and 3300 r.p.m. Further, at the approximately half-way intermediate speed of 1800 r.p.m. more than half this advance must have occurred, in fact as big a fraction (of the total) as it is possible to get, up to two-thirds. (4) The magneto shall be capable of complying with the performance scheduled in (5), (6) and (7) below, after first having been subjected to :- Contd. | ||