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).
With a diagram discussing modifications to coupling teeth for the silent second speed.
| Identifier | ExFiles\Box 179b\1\ img337 | |
| Date | 23th February 1933 | |
| HS.{Lord Ernest Hives - Chair} ) FROM HDY.{William Hardy} ORIGINALLY HDY{William Hardy}/1/M23.2.33 BENSPORT - SILENT SECOND SPEED. Y.4.S.S.3 With reference to the 2nd. speed working out as reported in HS{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}1/KT21233, we understand that the coupling teeth are of the drilled type and not of the shape called for on our [strikethrough] scheme, as the necessary tools for the latter operation were not available in time. As the 2nd. speed on Peregrine with the correct shape teeth has not worked out so far it may be that the teeth have something to do with the trouble. We suggest that if any more couplings are made with the drilled teeth, the teeth on the internal member should be truncated as shewn in sketch in order that it shall be certain that the load is taken approximately tangentially to the pitch circle. A further modification that should be tried if the correct teeth do not cure the trouble is the trepanning shewn on N. sch. 3631. [Diagram of gear teeth with a 90° angle indicated] HDY.{William Hardy} [signature] | ||