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 results from a sparking test, comparing outcomes at different gap sizes under correct and incorrect current directions.
| Identifier | WestWitteringFiles\K\September1923\ Scan42 | |
| Date | 5th September 1923 guessed | |
| TABLE OF RESULTS. Size of gap. Direction of current right. Direction of current WRONG. 1.0 mm. Sparking regular on gaps. 2.0 mm. Ditto. 3.0 mm. Ditto. 4.0 mm. Ditto. 5.0 mm. Ditto. 6.0 mm. Ditto. 7.0 mm. Some sparking between points and spigot. 8.0 mm. Frequent sparking from all points to spigot, some via surface of bulge on moulding. Sparks wander. 9.0 mm. Fairly frequent sparking from all points. Sparking almost ceased on gaps. Sparks wander. 10.0 mm. Sparking entirely taking place in distributor. Sparks wander. 11.0 mm. Sparking entirely in distributor. Sparks wander. 12.0 mm. Ditto. 13.0 mm. Ditto. Direction of current WRONG. 1.0 mm. Sparking regular on gaps. 2.0 mm. Ditto. 3.0 mm. Ditto. 4.0 mm. Ditto. 5.0 mm. Ditto. 6.0 mm. In the case of one rotor, an occasional spark from No.5 point in distributor. 7.0 mm. Frequent sparking from points 3 & 5. Some strike moulding and travel over surface to spigot. 8.0 mm. Very frequent sparking from points 3 & 5. Fairly frequent from points 1,2, 4 & 5. Sparks steady 9.0 mm. Sparking fairly frequently and steadily from points 1,2, 4 & 5. 10.0 mm. Frequent sparking from all points. Also between rotor blade & condenser rivets. Bad missing on gaps. Sparks steady. 11.0 mm. Almost all sparks pass in dist., between point & moulding above spigot. Also frequently from rotor to condenser rivets. 12.0 mm. All sparks pass in dist. Sparks steady. Very frequent between rotor and condenser. Contd. | ||