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 and modifications for a synchromesh 2nd speed gearbox fitted to a Vulture chassis.
| Identifier | ExFiles\Box 15\5\ Scan381 | |
| Date | 7th March 1934 | |
| To Sg.{Arthur F. Sidgreaves - MD} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to Mor. c. to E* c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Hdy.{William Hardy} X7310 Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}2/KW. 7.3.34. Synchromesh 2nd Speed Gearbox. We have fitted the first gearbox of this type to the Vulture chassis. Originally the box had wide ratio ground gears. The side shaft was not good; nor was the silence of the indirect gears up to 20/25 standard, which means they were far below the 40/50 standard. Until it had had considerable use and deliberate slipping of the cones, the 2nd speed synchromesh would not work, the teeth engaging before the speeds had synchronised, there being no feeling of baulking of the gear lever. On dismantling the gearbox we found several of the 2nd speed teeth broken, bits being embedded in the grooves of the bronze cone. New parts were fitted, and at the same time close ratio unground gears correct for the Vulture chassis. The synchromesh worked well for a time and then became erratic. The gears were very noisy, the sideshaft being audible up to quite high speeds in top gear. On dismantling the box the 2nd speed teeth were again found damaged. We think it very possible that the teeth are damaged by accidentally letting in the clutch when the gear lever is only half way into 2nd. The fragments then broken off prevent a nice operation of the synchromesh until they have been forced in the grooves of the bronze cone. While the box was dismantled the gears were given a further burnishing, but were no quieter afterwards. 2nd and 3rd speeds were now inclined to crash and top gear to stick, all of which was improved by slipping of the cones. This is done by trying to engage a gear without putting out the clutch. | ||