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).
Issues with the Synchromesh 2nd speed Gearbox in the Vulture, including gear noise, crashing teeth, and potential improvements.
| Identifier | ExFiles\Box 123\3\ scan0149 | |
| Date | 8th March 1934 | |
| X4704 To E.{Mr Elliott - Chief Engineer} from HDY.{William Hardy} c. Sg.{Arthur F. Sidgreaves - MD} Wor{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} La.{L. A. Archer} Hs{Lord Ernest Hives - Chair} HDY.{William Hardy}2/HP.8.3.34. Synchromesh 2nd speed Gearbox in Vulture. With reference to Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}2/KW.7.3.34, I am not convinced that we yet know much about the silence characteristics of this box as so far it has not been run with all of the gears ground. The wide ratio gears had unground layshaft gears and the close ratio gears are all unground except the 1st speed and reverse. With regard to the crashing of the teeth, as the synchronisation is sometimes quite good, it is evident that not much alteration is needed. We can always cure crashing which occurs with normal operation of the gear lever by increasing the angle of the locking cam, but we do not wish to do this until other means have failed as the gear change is made heavier. Damage may be done to the engaging teeth of any synchromesh change if the clutch is let in before the change lever is fully home and we cannot see any reason why the new 2nd speed should be any more susceptible to this than the gears of our standard boxes of which we have had no complaint. The picking up of the 1st gear teeth is, of course, evidence of too high an intensity of pressure but until the box has been put through the standard dynamometer test we are not sure of the extent of the deficiency. We have so far not adopted tip relief of the wheel teeth on gearbox gears but it appears that in this case we should certainly obtain benefit from this practice. We cannot do this at the moment, however, without sending the gears to be ground outside. If we are able to use a smaller cone angle as is done on American cars we can have less leverage of operation and wider 1st speed gears without sacrificing the light control which we now have. E.{Mr Elliott - Chief Engineer} | ||