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).
Series of tests on an E.A.C. servo on a brake testing rig.
| Identifier | WestWitteringFiles\L\2Jan1924-March1924\ Scan11 | |
| Date | 22th January 1924 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. x9910 REF: Hs{Lord Ernest Hives - Chair}/Bm/LG22.1.24. E.A.C. SERVO TESTS. We have carried out a series of tests with the EAC. servo on our brake testing rig. For purposes of comparison we have evolved a mechanical gain factor which is illustrated on the graph. The first series of tests were to determine the effect of load, speed and temperature on the performance of the servo. For the load and speed test (Graph B. and C.) the temperature of the inside drum was maintained at 100°C by means of water. During the high speed test the surfaces of the Ferodo obviously got very hot in spite of the cooling water in the drum. For the temperature effects we ran the drum for 5 mins. with a load equivalent to 100 lbs. pedal pressure(with modified leverages, distributor efficiency 70%) and a speed equivalent to 14 1/2 m.p.h. on the road. At the end of this period the drum attained a dull red heat. If we attempted to either double the speed or load in this test without any cooling, the drum became red hot in under 2 minutes. As the performance of the servo varied during these tests (due to causes elucidated below) the curves on this graph are the mean of a number of runs. We observed during these first tests that when once the Ferodo had become thoroughly scorched by contact with the red hot drum, the co-efficient of friction of the Ferodo went up and its capacity for withstanding wear, down. contd;- | ||