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).
Road tests on front wheel brakes.
| Identifier | WestWitteringFiles\K\October1923\ Scan67 | |
| Date | 20th October 1923 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} ORIGINAL. EXPERIMENTAL REPORT. Expl. No. 9940 REF: Hs{Lord Ernest Hives - Chair}1/LG20.10.23. SECRET. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to Da.{Bernard Day - Chassis Design} c. to EY. ROAD TESTS ON FRONT WHEEL BRAKES. We ran a 40/50 HP. chassis on the road for the first time last night fitted with front wheel brakes. The front brakes were operated by the foot pedal - the rear brakes were operated by the hand lever. We had arranged a 20 HP. brake equaliser under the steering in approximately the same position as shown on the drawing. With the first application of the front brakes we got most violent jaggers. These were similar to the rear brake jaggers we had with the countershaft brake except the period is much higher and it was accompanied by considerable noise. Our impression is that these jaggers are caused by the fact that when the brakes are applied, the axle and springs twist and carry with them the brake lever so that the brake pressure is increased and the wheels momentarily skid which releases the twist - it then builds up again. After the brake had been used and had become hot, it was more difficult to produce these jaggers but they occasionally came on. The steering was arranged with the standard amount of backward lean on the pivots and the steering of the car was quite normal. Whenever, however, we attempted to steer - with the brakes applied, the steering ran away out of control. This was undoubtedly caused by twisting of the axle and springs, contd:- | ||