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 impracticality of adopting 57 grooves in a car dynamo armature.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 101 | |
| Date | 16th May 1927 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. ORIGINAL RE CAR DYNAMO In reply to your R10/M2Q.4.27, it does not appear practicable to adopt 57 grooves in the armature. EFC. | ||