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).
Servo plate deflection, wear, and efficiency under load, including a table of mechanical advantage.
| Identifier | ExFiles\Box 73\1\ scan0131 | |
| Date | 25th March 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}/ACL/LG25.3.24. With a load equivalent to a pedal pressure of approx. 70 lbs. the outer servo plate showed signs of deflection by giving the Ferodo hard contact with its inner circumference only, and reducing the mean radius from 3" to 2.5". The deflection apparently took place at the annular groove on outer plate. The servo keeps exceptionally cool even when opera- ting under continuous heavy loads. Total running time was 28 hrs. under load; there was no appreciable wear of fabric. The reduction gear was fre- quently examined and found quite satisfactory. No leakage of oil to the friction discs was experienced. The efficiency of the servo did not increase when run at higher speeds. Engine speed throughout test 1500 = 30 m.p.h. approx. Figures below are average of 6 tests and corrected for levers etc. P. W. Mech: advantage. 2 4.35 8.60 7 6.12 3.475 12 7.58 2.52 17 9.32 2.175 22 11.25 2.04 27 12.125 1.75 32 14.55 1.8 37 16.5 1.78 Note :- 42 17.71 1.78 Servo just warm 47 18.91 1.6 after each test. 52 20.5 1.56 57 22.19 1.55 62 24.375 1.56 contd:- | ||