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).
B.S. Chassis starter motor design, comparing straight and helical teeth.
| Identifier | ExFiles\Box 64\4\ scan0090 | |
| Date | 11th October 1928 | |
| To EFC. X7655B BY/RD8/ML11.10.28. B.S. CHASSIS - STARTER MOTOR. I have discussed R's design of this unit with BY.{R.W. Bailey - Chief Engineer} and we agree that no provision has been made to cushion the outward or disengaging blow other than the fibre washer provided , the explanation of this being that R.{Sir Henry Royce} had in mind straight teeth and therefore the need for this cushion was absent (See R1/M23.12.27). We would draw your attention to the fact that straight teeth are instructed for the 3 S.S Chassis at present being built and from the point of view of silence the straight teeth are preferable as they can be ground. R.{Sir Henry Royce} suggests trying a set at 10° but any alteration in the angles means new bottom half crankcase and gearbox every time. As far as we know the straight teeth (corrected) on 14-EX are quite satisfactory. If however, you are of the opinion that the 5° helical is desirable, the 3rd. S.S. chassis could have this fitted, perhaps you will let us know. BY/RD. | ||