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).
Comparison table of magneto performance and timing specifications for various makes.
| Identifier | ExFiles\Box 4\5\ 05-page154 | |
| Date | 23th March 1921 guessed | |
| Top Center: -1B A.{Mr Adams} Left Margin: A.E.D. or T. Dept. | Magneto. | Degrees of make. | Maker's make advanced. | Maker's break advanced. | Our break advanced. | Our break Retarded. | lowest speeds for 5.5 m/m.{Mr Moon / Mr Moore} Adv. | lowest speeds for 5.5 m/m.{Mr Moon / Mr Moore} Cent. | lowest speeds for 5.5 m/m.{Mr Moon / Mr Moore} Retd. | Remarks. | |---------------|------------------|------------------------|-------------------------|---------------------|---------------------|---------------------------------|----------------------------------|---------------------------------|----------| | Watford. | 154.5 | -57° | 97.5° | 97.5 | 131.5 | 150 | 250 | 340 | Magneto No.45638. | | " | 155 | -59° | 96° | 94.5 | 128.5 | 156 | 226 | 320 | " " 45452. | | " | 163.5 | -78.5° | 85° | 85° | 117° | 150 (handwritten above: 180 (struck through) 156) | 140 | 136. | Maker's range. | | " | 160.0 | -92° | 67" | 96 | 130 | 160 | 190 | 150. | Retd posn. same as o maker's. Adv.posn. 29 later than maker's. | | R.{Sir Henry Royce} Bosch. | 82.5 | +11.5° | 94° | 94 | 128 | 260 | 170 | 246. | Adv.posn. same as makers Retd.posn. 2.5° earlier than maker's. | | U.S.A. Bosch. | 153 | -53.5° | 99.5° | 99.5 | 133.5 | 120 | 162 | 240. | Adv.posn. same as makers Retd.posn. 3.5° earlier than maker's. | | U.S.A. Bosch. | 155.5 | -79° | 76.5° | -- | -- | 150 | 290 | 530 | Maker's range. | | dixie. | 73.5 | -29° | 53.5° | -- | -- | 180 | 180 | 185 | Low speed sparking unaltered by advancing. | | Conner. | 78 | +14.5° | 92.5° | 107 | 141 | 250 | 260 | 170 | Retd.posn.same as makers Adv.posn.14.5° later than maker's. | | B.T.H. | 100.0 | -27.5° | 72.5° | 62.5 | 96.5 | 244 | 192 | 220 | Datum slightly indefin-ite. Full adv. not secured owing to fouling. | Bottom Right: Cont. | ||