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 RRM scheme of brakes, detailing its operation, servo action, and an investigation into brake lag.
| Identifier | ExFiles\Box 73\3\ scan0008 | |
| Date | 20th March 1924 | |
| R.R. 403A (20H) (D.A. 652 20-3-24) J.B.D. EXPERIMENTAL REPORT. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. RG.{Mr Rowledge} c. to DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} WOR.{Arthur Wormald - General Works Manager} Expl. No. 9940 4214 REF:Hs{Lord Ernest Hives - Chair}3/LGL.5.24. Handwritten: +9940 S E C R E T. Handwritten: +9940 RRM. SCHEME OF BRAKES. Handwritten: +4214 The car fitted with the RRM. scheme of brakes we find is liable to brake jaggers. If the car is travelling at a reasonable speed and the brake pedal is operated quickly, only the slightest amount just sufficient to take up the clearance of the servo shoes, the servo, being able to overrun the foot pedal, takes up the clearance in the front brakes and brings the shoes in contact with the drum with a sog. It is impossible for the servo to take up the rear brake clearances before the brake pedal is depressed owing to the action of the dogs on the countershaft. The fact that the equaliser can only work on to the front brakes, speeds up its action. The effect of this has the advantage that the 4-wheel brakes are applied evenly. Instead of there being any lag in the operation of the front brakes, the front brakes are actually in contact with the drums before the rear brake clearances are taken up. This applies even when the brakes are worn. We have been carrying out investigations to find the explanation why the lag on the RRM. scheme is not apparent when driving the car. Actually, the geometry lag is practically the same on the RRM. as on the DES.60 or Hispano. This we measure by putting the brakes on with the car standing then slowly moving the car until we can feel on the brake pedal when the servo has come on. contd:- | ||