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 analysis of a material, identified as micanite, with recommendations for using a pure grade of mica.
| Identifier | ExFiles\Box 168a\3\ img075 | |
| Date | 6th April 1939 | |
| -2- (1) The material burned for a short time. (2) A smell of hot resin or shellac was given off. (3) While warm the material was slightly sticky to the touch, but when cold it was quite dry. (4) After heating, the mica fell to pieces as though some cement or binding substance had been removed. We now feel confident that this material is a form of micanite i.e. flaked mica bound together by shellac. It is considered that a good quality pure mica such as 'amber' mica should be used for this purpose. As a next step it is thought that a machine should be built up using such a grade of mica in the commutator and tried out. RM{William Robotham - Chief Engineer}/NC. | ||