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).
Mr. Royce's opinion on the proportions of braking and adjustments to achieve a desired torque multiplication.
| Identifier | ExFiles\Box 5\3\ 03-page148 | |
| Date | 9th June 1925 | |
| X5940 To HS.{Lord Ernest Hives - Chair} from DA.{Bernard Day - Chassis Design} c. to RG.{Mr Rowledge} BY.{R.W. Bailey - Chief Engineer} SECRET DAL/M9.6.25. INDIA X.5940 X.5370 PROPORTIONS OF BRAKING. With further reference to Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG27.5.25., Mr. Royce does not approve of the suggestion to reduce the direct braking and increase the power of the servo. He considers that the direct braking is very valuable. It is appreciated chiefly when shunting in difficulty places in which the full effect of the servo lag, namely, from the full amount forwards to the full amount backwards, is experienced. We estimate that with the enlarged dia. of cam shewn on N.sch.2005 with a 45° angle, rod multiplication from the servo approximately .8 will be obtained, which corresponds to a torque multiplication of approx. 1.25 whereas we are trying for a torque multiplication of 1. If, in addition to this, we increase the radius from the brake shoe cam from .4 to .5, and the length of the sheet metal lever on the rear brake differential slightly, it will be found that this is practically the equivalent to a torque multiplication of 1., with the present system of levers and cams, and will give us we believe what we want. We find that the sheet metal lever requires to be reduced from 2.625 as given on N.sch.2005 to 2.150 approx., and that this length can be used on the front brake, so that the same lever will do for both. contd :- | ||