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).
Test report on a 'USA' 4-speed gearbox, detailing overheating issues and subsequent modifications.
| Identifier | WestWitteringFiles\M\2Jan1925-March1925\ Scan51 | |
| Date | 27th January 1925 | |
| 20 4 SPD G/BOX DEPT QUICK RESULTS! ORIGINAL S E C R E T. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} AJS. c. to EY. Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}1/LG27.1.25. X5310 TESTS ON 'USA' 4-SPEED GEARBOX. We have carried out further tests to those reported in our Hs{Lord Ernest Hives - Chair}6/LG20.1.25. We fitted the gearbox up again with the original standard parts and ran it at 50% maximum torque on the 1st. speed and on reverse in place of the full maximum torque which was used on the first test. The length of time was also reduced from half and hour to quarter of an hour. During the tests when running on reverse, the gear worked itself out continuously. On examination of the box it was found that the fork operating the reverse pinions had again over-heated. It showed from this test that the over-heating on the original gear started from the fork and worked along to the teeth on the gear. The following modifications were then instructed by E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} and AJS. and were carried out on the box :- 1. The dia. of the reverse pinion shaft was increased from .9 to 1.050". 2. The race of the roller bearing at the rear end of the reverse shaft was made solid with the shaft. 3. The sleeve carrying the reverse pinions was ground with a parallel bore to suit this shaft. 4. The forks actuating the reverse, 1st. and 2nd. speeds were cleared away so that there were only pads on the ends of the forks to move the gears. contd :- | ||