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.V. Servo endurance test.
| Identifier | ExFiles\Box 99\3\ scan0203 | |
| Date | 5th April 1939 | |
| HH1 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}4/JH.5.4.39. B.V. Servo Endurance test. This servo has been running on the gearbox rig. A load of 250 - 300 lbs. has been applied across the scissor levers for 2 1/2 seconds every half minute. The servo was examined after 52 hours running owing to judders which were caused by oil getting on the plate. This was due to an experimental water excluder turning round and preventing the escape of oil which was leaking from the oil seal on the gear-box. This type excluder has been replaced. The plate was cleaned and all parts examined. There were two cracks in the VG.90 plate which had been fixed by 12 small rivets but these were apparent when the plate was built up and are not serious. There was slight marking on the spindle where the sliding ball cage carrying the cast iron plate rubs. The end of the cage also showed signs of fouling where the servo had been applied. There was no pitting on the servo cams. All parts were cleaned, greased and reassembled. After a further 6 hours running smoke was reported to be coming from the servo. We disconnected the operating rig but the servo continued to heat. It was then found that the links which had been forced round by the servo, were locking the plate. These were freed and considerable slack was evident on the plate. The sliding bearing had seized on the shaft. In view of the good condition of the servo after 50 hours we consider this trouble to be caused by the continuous load to which the bent levers had subjected the bearings, aggravated by the continuous high temperature melting away the grease. | ||