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).
Experimenting with a 7.5 degree spiral pinion and gear ring for the Phantom II sequence starter gear.
| Identifier | ExFiles\Box 61b\3\ scan0228 | |
| Date | 9th March 1931 | |
| X6079 To Ry. from EFC. EFCl/ADl9.3.31. X.6080 PHANTOM II SEQUENCE STARTER GEAR. X.6079 We are anxious at this stage to make an up-to-date experiment of slightly spiral pinion and gear wheel teeth for the starter engagement. The angle of the spiral which we wish to try is 7½°. With the motor as at present arranged there have been, as you know, one or two cases recently in which the motor has failed to complete engagement and shown that we have not much in hand in the proportion of axial force to rotational torque. One of the reasons why helical teeth, with which some of the earlier experiments were made, were departed from was that at that time no damper was fitted to the motor and the armature thumped badly on disengagement. It was essential on that account to keep the spiral angle as small as possible and the experiment was made of dispensing with it altogether. Will you please now arrange to instruct experimentally two sets of pinion and gear ring with 7½° spiral angle but otherwise as at present standard. EFC. | ||