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).
Comparing the high and low-speed sparking characteristics of different magnetos.
| Identifier | ExFiles\Box 4\5\ 05-page359 | |
| Date | 8th December 1925 | |
| E.R. 4084 (30) M.N. 17-9-25. 1.M. EXPERIMENTAL REPORT. Contd. -6- Expt. No. REFER/T8.12.25. (12) High Speed Sparking Characteristics. The highest speed at which the magnetos were capable of firing regularly in sequence six 5.5 mm. three-point spark gaps in air in the fully advanced position were 3450, 4500 and 4500, respectively. (13) Low Speed Sparking Characteristics. The lowest speeds at which the magnetos were capable of firing regularly in sequence six 5.5 mm. three-point spark gaps in air in each of the three positions :- (a) Fully advanced. (b) Central. and (c) Fully retarded. of the contact breaker lever, were in accordance with the following table :- SPEED. MAGNETO. Advanced. Central. Retarded. Watford. 210 160 160 B.T.H. No.356071. 215 170 170 B.T.H. No.356147. 200 170 160 showing the B.T.H. to have quite good low speed sparking performance. These two B.T.H. machines are now on experimental chassis 98-NK and 44-PK, and a further report will follow in due course. The B.T.H. appears to have some advantage over the Watford in that the pulsation of the sleeve is not readily transmitted to the advance retard lever on the Contd. | ||