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 detailing the investigation and rectification of performance issues with a Peregrine servo motor.
| Identifier | ExFiles\Box 2\7\ B002_X 140 to 143-page11 | |
| Date | 25th January 1933 | |
| PEREGRINE SERVO MOTOR TESTS. Sketches of the various arrangements used throughout these tests are shewn on the attached blueprint. Each reading was taken after a short interval of about 1 min. to allow linings to cool, except where otherwise indicated. The servo was fitted with RAD.13 friction linings. The figures obtained shewed considerable falling off towards the higher input loads, i.e. an input of 350 lbs. did not give an output of 2.33 x the output at 150 lbs. input. It was at first suspected that this fall off was caused by distortion of the shafts, or their supports, which led to binding, as there was a visible movement of the end of the inner shaft downwards and rearwards when load was applied to the pedal. Readings were then taken with the anchorage in a horizontal position as there appeared to be less downward distortion in this case. There was no appreciable difference between the two results. The servo was dismantled for inspection. The main shaft appeared somewhat rough and showed signs of slight binding in the outer ones. The end of the shaft supported in the ball race at the gearbox end was also marked as though sticking, and it was noticed that when the shaft was rocked well out of line at its outer end, it would not slide as freely in and out of the race. The inner shaft was eased and polished with emery to give free sliding movement. The results are as shown in curve 1. The effect of supporting the end of the inner shaft by a jack, to prevent rocking was tried, with no improvement, the 'falling off' remaining about the same. It was then found that the bearing in the bridge piece was slightly out of line with that in the gearbox, throwing the linings out of truth with the plate. The servo was then returned to the shop for correction. Curve 2. The results after lining up of the bridge-piece showed a reduction in falling off, the curve being much straighter. It was concluded that this improvement was due to the better bedding of the linings over their whole surfaces after the lining up of the bridge piece. To obtain a higher output the linings were scraped by hand to bed evenly all over, but results were not much | ||