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).
The performance of tungsten points after a 5,750 mile test, noting sparking issues and physical wear.
| Identifier | WestWitteringFiles\L\2Jan1924-March1924\ Scan45 | |
| Date | 29th June 1929 | |
| RR 238 (180 BKS.) (SH57.29-6-29.) MP 224358 ROLLS-ROYCE LTD. INSTRUCTIONS. To Order No. PC 19 (2) Customer's No. 19 in steel, both of which it was decided to keep under observation. Tungsten Points At the end of 5,750 miles slight missing occurred at the spark gaps, accompanied by flashing at the points. Sparking was OK on 6.5 mm gaps at 8.0 volts with a reduction in the flashing at the points, but on returning to 12 volts, on 5.5 mm gaps, and more so when the speed was lowered, some missing occurred, as though the points were not quite able to cope with the current. Sparking with only slight missing was maintained to the end of the test, which constitutes the best performance with tungsten points so far obtained. The points themselves have the usual hard pitted, blue-black discoloured surfaces. The actual amount of wear is small, apparently a small transference. Signed Cont'd.{John DeLooze - Company Secretary} This Sheet must be filed on completion of the work. | ||