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).
Particulars of starter motors, including pinion thread angles and differences from standard models.
| Identifier | ExFiles\Box 64\1\ scan0236 | |
| Date | 15th August 1926 | |
| To EFC. X7620 15.8.26. STARTER MOTOR PARTICULARS. X.8620/50. X.7650/20. The two S. motor pinion thread angles are 55° 8' helix. (34° 52' spiral) 45° helix. (45° spiral) The angle of the pinion thread on S. motor G.2 is 55°8' helix. C motor differs from standard in the following respects :- . It has not the poles with the reduced cores. . The teazer winding has only 33 turns per pole. . It requires the new epicyclic reduction gear together with the pinion fitted with flanges. C.A.P. | ||