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).
To the technical committee regarding the design and application of helical gears.
| Identifier | ExFiles\Box 3\1\ 01-page132 | |
| Date | 6th March 1912 | |
| Recd. 11/3/12. Le CanadelHenry Royce's French residence. 6th March.1912. X182 C.J. and Technical Committee. Re Helical Gears. I believe the action of the above gears is somewhat similar to a worm and they should wear themselves quiet with running. The shape of tooth, therefore, is not of such importance, but preferably they should make contact principally on the pitch line. They should be made, however, with a good angle of action, say, 20 degs. obliquity, to avoid interference. I should like this confirmed by experiments. These gears are inexpensive and frictionless and are at present fitted to the marine engine half time shafts, where they are reported to be "very good so far". The most exacting turbine drives at the very highest speeds are fitted with this gear in the double form, to avoid end pressure, but the end pressure in the single form is not so great as with worm gearing, and can easily be taken by ball thrust bearings for such small gears as we require for engine details. F.H.R. | ||