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 spark gap measurements in millimeters for a 6-cylinder engine and coil at various speeds and loads.
| Identifier | ExFiles\Box 82\4\ scan0339 | |
| Date | 8th May 1936 guessed | |
| MEASUREMENT OF SPARK GAP IN m/m.{Mr Moon / Mr Moore} Speed miles/hr. Top Gear. | No. 1 Cyl. | No. 2 Cyl. | No. 3 Cyl. | No. 4 Cyl. | No. 5 Cyl. | No. 6 Cyl. | Coil Snap open | full load | Snap open | full load | Snap open | full load | Snap open | full load | Snap open | full load | Snap open | full load | Snap open | full load Idling | 2.0 | | 2.2 | | 2.5 | | 2.6 | | 2.85 | | 2.3 | | 3.85 Slow Running | 2.4 | | 2.9 | | 3.0 | | 4.0 | | 3.85 | | 3.05 | | 5.0 10 | 3.3 | 3.1 | 3.05 | 3.15 | 4.5 | 4.6 | 4.6 | 4.2 | 4.8 | 4.8 | 5.6 | 4.2 | 6.0 | 5.7 20 | 3.8 | 3.25 | 3.65 | 3.9 | 4.6 | 4.6 | 4.85 | 4.6 | 5.0 | 5.2 | 5.7 | 4.25 | 6.25 | 5.85 30 | 4.0 | 3.4 | 4.1 | 3.95 | 4.65 | 4.65 | 4.7 | 3.8 | 5.1 | 5.3 | 5.75 | 4.75 | 6.2 | 5.75 Idling speed - 350 R.P.M. Slow Running - 6 M.P.H. | ||