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).
Page discussing servo efficiency and theoretical brake distribution.
| Identifier | ExFiles\Box 5\3\ 03-page128 | |
| Date | 1st May 1925 | |
| EXPERIMENTAL REPORT. -2- Expt. No. REF Hs{Lord Ernest Hives - Chair}/Ral/1327.5.25. as suggested by you to avoid complication. As long as the units on the graph correspond with the units used for identifying the servo efficiency, the correct theoretical brake distribution can be read off as a percentage which will be independent of the units employed. In the case of the two sets of curves in question, however, the braking units themselves are directly comparable, they are the same units. We regret that in giving a preliminary figure for the servo efficiency, the words input and output should have been transposed. Actually for that servo output/input = 1.25 so that, tabulated, the figures are :- | | India. | E.A.C. reduced. | E.A.C. before reduction. | |---|---|---|---| | Front | 41.5 | 40% | 44 | | Rear | 58.5 | 60% | 56 | | Ratio Front/Rear | .71 | .666 | .785 | We have, however, since testing the original servo had an opportunity of testing a second servo. This was so much more efficient than the original one that we fitted 55° cams. The "conventional servo efficiency" output/input then varied from .8 with light loads gradually applied to 1.6 when the pedal was depressed suddenly and violently. This means that in an exceptional case the ratio front/rear would reach .785. From a rough calculation we estimate that theoretically a servo efficiency of 1 should be obtained from this servo with 55° cams, if it behaves in a similar manner to that of the EAC. Contd. | ||