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).
The development status and specifications for a four-wheel brake system.
| Identifier | WestWitteringFiles\L\April1924-June1924\ Scan42 | |
| Date | 27th May 1924 | |
| ORIGINAL SECRET TO R.{Sir Henry Royce} FROM DA.{Bernard Day - Chassis Design} DA{Bernard Day - Chassis Design}1/M27.5.24. Copy to - E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. 3. FOUR WHEEL BRAKES. X9940 X9910 The position of the work on these brakes is as follows:- (1) The adopted scheme of brake operation, namely, the RRM. scheme of semi-servo operation plus servo braking backwards is generally quite satisfactory. The design of servo and operating linkage recently sent through works well, and with the exception of slight modifications to the adjustment which are coming through immediately, should go on for production. The ratio between the front and back braking has yet to be decided upon experimentally. Derby have full instructions to enable this to be done. The exact angle of the cam on which the force of the servo depends has also to be decided upon experimentally. We understand that an angle of 55° has given the best results up to the present. (2) Mr. Royce agrees to the use of the standard 40/50 side steering tube with balanced (i.e. not set-up) buffer springs at each end except that the latter are reduced in rating, and have reduced initial load. The rating found at Derby to be most satisfactory was 1000 lbs. per. in. with an initial load of 100 lbs. (3) It is understood that the lock obtained on the front axle is satisfactory, and that the whole of the front axle parts are going through for production. The cross steering tube to be set .75 in centre. (1) | ||