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).
Brake jaggers, detailing tests on Hispano, Isotta, and Delage cars.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan34 | |
| Date | 1st May 1924 | |
| B.R. 493A (20H) (D.A. 652 20-2-24) J.H.D. EXPERIMENTAL REPORT. [REDACTED To/From/Cc/Bc block] ORIGINAL Expl. No. Hs{Lord Ernest Hives - Chair} 4214 REF: HsL/1/M 5.24 1559 9940 S E C R E T. BRAKE JAGGERS. HISPANO CAR. We have endeavoured to produce brake jaggers on the Hispano car but have not been successful. We arranged direct foot pressure to the front brakes only using a leverage of 18 to 1 measured to the centre of the shoes. We found with this we could not get any front braking owing to the springiness of the drums and operating mechanism. With the maximum pedal pressure we could get on, which was still not sufficient to give any braking, the drums deflected .030". With the assistance of the servo we can, of course, lock the front wheels on the Hispano. We carried out tests on one of our own cars on which we had bad brake jaggers, by gradually reducing the stiffness of the brake drums. We first turned off the flange on the edge - this made no difference. We then reduced the thickness of the drum. We found when we had reduced it by .150" in thickness, the jaggers had disappeared and could not be produced. The drum deflected when the brakes were applied. On the Isotta car, we tried on there to produce front brake jaggers and finally had to give it up because of the flexibility of the front brake drums. We could not obtain any solid braking. The Delage car also had very flexible brake drums. When we found we could not get any braking contd:- | ||