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).
Drawing of standard and experimental 40/50 56 coil armature slots with dimensions.
| Identifier | ExFiles\Box 62\3\ scan0173 | |
| Date | 4th February 1931 | |
| X6076 4/2/31 X.6076. 40/50 56 COIL ARMATURE SLOTS. Late standard with 18 SWG. conductors, and experimental with 17 SWG. conductors. .600 .515" .170" .188" .586 .680" | ||