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 wear rates of different brush types, comparing a new type to the standard and noting an ongoing test.
| Identifier | ExFiles\Box 165\6\ img064 | |
| Date | 29th June 1920 | |
| RR 238 (150 BKS.) (BH57.29-6-20.) MP 224358 ROLLS-ROYCE LTD. INSTRUCTIONS. To Order No. Customer's No. 2 19 edges of the segments. The wear of the brushes is:- Positive .027", Negative .037", Control .024". These amounts are somewhat more than the average obtained with Morganite ZG2. brushes. This test has not shown up any distinct advantage in the EG_ brushes over the standard grades, but further experience might show an absence of tendency to screech which sometimes persists on standard machines. A similar test with Le Carbone EG 217 brushes is proceeding. Signed WGH This Sheet must be filed on completion of the work. | ||