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).
Comparison table of starter motor specifications for small cars.
| Identifier | ExFiles\Box 61b\3\ scan0158 | |
| Date | 25th February 1921 | |
| X.543 K543 STARTER MOTOR TABLES. (Additional sheet II - Motors for small car). STARTER MOTOR. X.4342V. C.A.V. SC X.4342S. Smith SS{S. Smith} X.4384. R.R. Goshawk K.4342L. Lucas CARCASE Diameter: 4.625, 4.500, 4.500, 4.500 Length: 4.725, 4.10, 4.500, 4.350 Thickness: .312, .375, .250, .325 ARMATURE Diameter: 2.746, 2.500, 2.850, 3.003 Active length: 2.900, 1.650, 2.500, 2.600 END CONNECTIONS Length of overhang at driving end: .80, 1.10, .925, .650 Length of commutator connections Excluding m.{Mr Moon / Mr Moore} spokes: 1.15, 1.45, 1.10, .700 Ditto Including com spokes: 1.35, 1.6, 1.30, .850 R.R. 63 (M.T.D.) (S.R. 25-2-21.) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2109. | ||