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 sequence starter motor to engine reduction gear ratios.
| Identifier | ExFiles\Box 64\1\ scan0258 | |
| Date | 4th December 1926 | |
| X.7620 4.12.26. X.8620. SEQUENCE STARTER MOTOR TO ENGINE X.7620. REDUCTION GEAR RATIOS. Original total reduction 32 : 1 Second " " 30 : 1 As first arranged on chassis:- Motor epicyclic ratio 4 : 1 Pinion to engine. 65 : 9 Total reduction 28.87 : 1 As secondly arranged :- Motor epicyclic ratio 96 : 31 Pinion to engine 65 : 9 Total reduction 22.37 : 1 As thirdly arranged :- Without epicyclic 13 : 1 | ||