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).
The B.50 servo mechanism after a 107-hour endurance rig test.
| Identifier | ExFiles\Box 112\1\ scan0134 | |
| Date | 8th July 1938 | |
| 841 To By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Da{Bernard Day - Chassis Design}/Hdy.{William Hardy} Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}S/JH.8.7.38. B.50. SERVO AFTER 107 HOURS ON SERVO ENDURANCE RIG. A load of 300 lbs. was applied for approximately 2 seconds in each minute across the scissors levers. The bronze spring plate had been modified by having a thin ring soldered round the outside unfortunately owing to overheating this came away leaving the spring plate free to rotate and relieving it of all load. On examination the lining (Halo 3L) showed only .002" wear but owing to over heating the lead had been melted out of it on the outside edge and after this it squeaked on every application of the load. The cam surfaces were good and only slightly marked. The three row ball bearing which had been packed with grease originally was almost packed with hard dust and grease. The races did not appear groved but showed discoloured lines on the shaft where the balls had not been rotating. We think it will be necessary to seal this bearing to prevent it becoming blocked with dust off the friction disc as at present the spring plate acts as a diaphragm and when correctly fitted pressure is built up inside on each application which will tend to blow the dust formed through this bearing. We do not think a vent hole would help as in this case the edge of the disc was free during the greater part of the running and there cannot have been much pumping action. The thrust bearing for the spring plate was not tested properly in this test owing to the edge outside becoming free and relieving it of all load. It was also rotating with the shaft. There were however circular cracks on the centre portion of the plate. Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems} | ||