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).
Table of results from magneto performance tests.
| Identifier | ExFiles\Box 4\5\ 05-page153 | |
| Date | 23th March 1921 | |
| XU30 /A.{Mr Adams} G.A.P 23.3.21. X.430. - TABLE OF RESULTS OF MAGNETO PERFORMANCE. Magneto. | Type & No. | X. No. | (1) Height (lbs) | (3) Air gap | (4) H.T. Safety gap (mm) | Platinum gap (inches) | (6) Range °. | Make ratio | (13) Utility test spark lengths (mm) (a) | (h) | (c) | (d) ---|---|---|---|---|---|---|---|---|---|---|---|--- Watford. | E.6 40886. | 2375 | 11.7 | .006 | 6.85 | .020 | 30 | .858 | 7.0 | 6.7 | 5.7 | 3.8 " | E.6. 44258. | 2375 | 11.7 | .006 | 6.85 | .022 | 30 | .861 | -- | -- | -- | -- (Magneto No.45168) " | E.O.6a 45993 | 4181a. | 12.7 | .006 (.003 between sleeve & pole shoe) | 7.2 | .009 | 32 | .906 | 7.0 | 6.7 | 5.7 | 4.2 (magneto No.46988) " | E.O.6b 48919 | 4181b. | 12.9 | .006" (.003 between sleeve & pole shoe) | 7.0 | .012 | 63 | .888 | 6.3 | 6.3 | 6.3 | 5.0 R.Bosch | Z.E.6 2571556 | 427 | 13.25 | .008 | 9.9 | .014 | 36.5 | .458 | 8.5 | 8.3 | 8.1 | 5.0 U.S.A.Bosch | Z.E.6 2993784 | 3916 | 15.1 | .005 | 8.7 | .026 | 37.5 | .850 | 7.6 | 7.2 | 4.3 | 4.2 U.S.A.Bosch | B.6. 3002660. | 3917 | 11.0 | -- | -- | .027 | 35.5 | .864 | -- | -- | -- | -- Dixie. | Aero648 718237. | 3724. | 14.1 | -- | -- | .022 | 39. | .407 | 8.0 | 6.5 | 4.0 | 2.0 Conner. | C.M.1 | 4210. | 16.1 | .006 | 8.7 | .010 | 48.5 | .433 | 9.5 | 8.6 | 5.4 | 3.6 B.T.H. | P.M.6 R311941 | 3515 | 10.25 | .003" (taken from mother machine) | 7.6 | .012 | 45.5 | .556 | 6.6 | 6.6 | 6.0 | 6.0 Contd. | ||