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).
Specification table for the Lucas Magneto Type ERS No. 50, comparing distributor dimensions.
| Identifier | ExFiles\Box 40\2\ Scan091 | |
| Date | 21th April 1926 guessed | |
| X8793 LUCAS MAGNETO TYPE ERS. No.50. x x Relative distributor dimensions. Suggested relative dimensions. Pitch. 1.00 1.00 Make ratio. .605 .56 Range. .32 .34 Forward overlap at full advance. .165 .10 Ditto at full retard. .485 .44 Backward overlap at full advance. .22 .20 Ditto at full retard. -.10 -.14 Brush + segment. .78 .74 B + S + M 1.385 1.30 Insulation dist. I. .385 .36 EFC. | ||