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).
Test results for an ignition system, detailing secondary milliamps, primary point gap, and contact breaker timing angles.
| Identifier | ExFiles\Box 48\2\ Scan199 | |
| Date | 14th May 1926 guessed | |
| -5- (14) Secondary milliamps : Maximum :- 5.5 Minimum :- 3.0 (15) Primary point gap after previous tests :- .010" Primary point gap .008" Contact breaker timing. Table 1: Make. | Break. A. {Mr Adams} | 8° | 93° R. {Sir Henry Royce} | 72° | 153.5° Table 2: Retard. | Advance. Make. | 72° | 8° Break. | 154° | 94° Make. | 252° | 188° Break. | 333° | 272° Make ratio:- .461 Primary point gap :- .016" Contact breaker timing. Table 3: Make. | Break. A | 11.5° | 90° R | 75° | 151.5° Table 4: Retard. | Advance. Make. | 75° | 11° Break | 152° | 91° Make. | 255° | 192° Break | 331° | 269° Make ratio:- .430 Average variation of Make = 1 1/2 ° " " " Break = 1 1/2 ° | ||