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).
Tests conducted on the reverse gear of a 25 HP synchromesh gearbox.
| Identifier | WestWitteringFiles\W\September1931-November1931\ Scan056 | |
| Date | 24th October 1931 | |
| ORIGINAL To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Ds. c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}1/KT.24.10.31. 25 HP. SYNCHROMESH GEARBOX. X5310. TESTS ON REVERSE GEAR. (1) Complete to N.Scheme. The car was run on the road for 10 minutes full torque, at the end of which it was found that the reverse gear had seized, it being impossible to slide the shaft in the bronze bushes which were assembled with .0015 clearance. (2) For this test the clearance was increased to .002" and two spiral grooves were machined in the bushes throwing the oil outwards on both sides from the central lubrication of the bush. Only two keys were fitted for retaining the loose pinion. The car was run on the dynamometer and the shaft seized after 2 minutes. (3) The clearance was reduced to .0015, the spiral threads retained. An additional oil hole was drilled through the front of the front bush from above. After 7 minutes half throttle the shaft had seized. For these three tests Amber A.{Mr Adams} oil was used. (4) The bushes were whitemetalled, retaining the oil grooves and additional oil hole, and were fitted with .0035 clearance. 5 pints of half and half Castrol XL. and Cearease were used. After two runs, one of 5 minutes and one of 10, at full torque, the shaft was quite free. The oil was drained and Amber A.{Mr Adams} was used, and again after 10 minutes the shaft was free. The gearbox was quieter with the mixed oils than with the standard Amber A.{Mr Adams} On dismantling, the whitemetal was in fairly good condition, the box being reassembled for 18.G.IV. 10,000 miles. During all these tests the gear had, after 2/3 throttle, a tendency to jump out requiring 4 lbs at the end of the gear lever to hold it in. The torque delivered is 150 lbs.ft., and the upward load on the front bush about 1200 lbs. To prevent the gear coming out of mesh we shall try a stiffer shaft. Furthermore, due to both gears trying to engage simultaneously, it was always difficult to engage gear. The 2nd. motion gear is therefore being given a lead of .030". Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||