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).
Gearbox testing, detailing damage to the reverse gear and other components after dynamometer and road tests.
| Identifier | WestWitteringFiles\M\2Jan1925-March1925\ Scan40 | |
| Date | 1st January 1935 guessed | |
| contd :- -2- The car was run on the road wheel dynamometer for half an hour on 3rd. gear. half an hour on 2nd. gear. half an hour on 1st. gear, and half an hour on reverse - at maximum torque, 1000 engine revs. When the car was tested on the road afterwards, it was found that the reverse gear was much more noisy. When the box was dismantled it was found that the small pinion on the reverse shaft and the large 1st. speed gear wheel which it engages with, were discoloured by heat. The teeth on the small pinion were very badly damaged. The fork for moving the reverse pinion had been very hot and was badly worn, as though the gear had been trying to force itself out. The reverse pinion and the 3rd. speed wheel which it engages with were also damaged but were not discoloured. The marking on the teeth appeared to shew that the reverse pinion unit shaft had been deflecting torsionally. The 1st. speed pinion was also badly discoloured and the fork engaging it had been very hot. On there the bedding appeared to be slightly on the cross, not so marked as on the reverse pinion. On the standard 3-speed box for the 20 HP. we have run nearly 200 hrs. on 1st. speed. These tests were made in conjunction with the failure of the bevel gear pinion. When carrying out those tests we ran on 1st. gear continuously maximum torque. The 4-speed box is being built up again with the contd :- | ||