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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 efficiency and brake pressure modifications to achieve more equal braking.

Identifier  ExFiles\Box 30\6\  Scan143
Date  11th January 1924
  
R.R. 403A (40 H) (EL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary}

SERVO EFFICIENCY JAGGERS

EXPERIMENTAL REPORT.
Expl. No. 1559
9940
9910
REF:Hs{Lord Ernest Hives - Chair}4/LG11.1.24.

To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair}
c. to CJ. RG.{Mr Rowledge}
c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer}
c. to E.{Mr Elliott - Chief Engineer}

BRAKES.

As the efficiency of the servo is much higher than was originally anticipated, the proportion of pressure on the front and rear brakes on the cars we have been testing has been very unequal. We have compromised to a certain extent by fitting stronger springs to reduce the pressure on the servo. This of course, was inefficient. We have modified a car in order to give us equal pressure on the front and rear brakes. This still leaves the rear with a definite advantage owing to the larger size brake drums and the servo acting as a countershaft, brake. Attached are photostats which give particulars of what we have done.

On the road we have got more equal braking with this arrangement than we have been able to obtain previously. It gives better results than any of the cars we have taken to WW. and also the servo does not overheat to the same extent. It is possible, of course, to criticise it. The results are not always consistent - for instance, at low speeds we obtain excellent braking - at high speeds, it is not sufficiently effective and we have found it necessary to slightly increase the leverage to the servo. We must always allow ample margin on the rear brakes because we know with the present car with the brakes operated by foot pressure, the difference in pressure required on different cars, varies considerably. We have two cars running with this arrangement.

contd:-
  
  


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