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).
Clutch plate wear, adjustments following a test run, and gear case temperature.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan271 | |
| Date | 7th September 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF: Hm{Capt. W. Hallam - Head Repairs}/AR/LG1 7.9.25. to be fitted when the 'worn' position has been reached. If thicker adjusting plates are not inserted at this point, the piston will eventually come up against the ends of the cylinder, preventing further motion of the toggle and causing the clutch to slip. The angles of the toggle lever when new should be equal ± for each gear viz., 16½° on each side of the central position. From the measurements taken after the 4½ hrs. run, it was calculated that to bring the levers back to the 'new' positions, the high gear adjusting plate should be .0085" thicker, and the low gear plate .0212" thicker, and thicker plates to these dimensions were therefore inserted. No slip was observed in either clutch during the 4½ hrs. run. After the thicker plates had been fitted, the engine was run for a considerable time to check further wear in the plates viz., 1 hr. on low and 1 hr. on high gear alternatively for 5 hrs. At the end of the test the change speed operating mechanism occupied the same positions as at the beginning of the test, showing that no further bedding down had taken place in the clutches. It was concluded that the wear experienced in the first place was due to 'bedding in' of the plates, rather than to actual wear. (2) GEARCASE TEMPERATURE. It was noticed that the gear case gets hot when running (hotter than that of single reduction gear) and it was suggested that the plates in the clutch, that is supposed to be disengaged, cannot free themselves sufficiently to contd :- | ||