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 lowest speeds in R.P.M. for regular firing on various magnetos with 5.5 mm gaps.
| Identifier | ExFiles\Box 4\5\ 05-page152 | |
| Date | 25th July 1922 | |
| C.A.P X.430 - MAGNETOS. TABLE OF LOWEST SPEEDS IN R.P.M. FOR REGULAR FIRING ON 5.5 mm. GAPS IN ATE. CHAIN DRIVE. N.B. Test range between advance and retard 34° in all cases. | Magneto. | Type & No. | X. No. | Lowest speeds. | | | Remarks. | |---------------|-------------------|--------|----------------|------|------|-------------------------------------------------------------------------------------------------------------------------------------| | | | | Adv. | Cent.| Retd.| | | U.S.A. Bosch. | ZR.6. Ed.{J. L. Edwards}19 3385190 | 3916 | 58 | 105 | 150 | Advanced position same as makers. Retard position 2° earlier than makers. | | Watford. | E06c 50410. | 4181. | 210 | 200 | 200 | Advance and retard limited by movable sleeves attached to cam ring. Therefore range the same as makers. | | Watford. | EL06 55044. | 4275 | 67 | 68 | 69 | Advance and retard limited by movable sleeves attached to cam ring. Retard position same as makers. Advance position 28° later than makers. | 25.7.22. | ||