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).
Experiments to improve the silence of the 25HP synchromesh gearbox helical trains.
| Identifier | ExFiles\Box 179\1\ img176 | |
| Date | 19th December 1931 | |
| COPY. FROM DA.{Bernard Day - Chassis Design} C. to Mr HS.{Lord Ernest Hives - Chair} IUC. 25HP. SYNCHRO MESH GEARBOX. DA{Bernard Day - Chassis Design}1/419.12.31. X5310. Herewith is N. sch. 3396. showing the following experiments, the object of which is to improve the silence of the helical trains: (1) Wider helical gears. (2) Finer pitch, namely, from 14 to 16 diametral pitch. (3) Slightly increased angle of helix. We understand we cannot grind an angle exceeding 35º therefore the suggestion to use 45º is probably not practical, but in any case it is only to be used as a last resort. 34º 35 mins. which is the nearest to 35º that we can get should however be tried. It will be noticed that the 3rd. speed driven wheel has had its bearing appreciably increased in length. I.A. [STAMP: RECEIVED 1931 DEC 21] | ||