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 tests investigating 'brake jaggers' by modifying Ferodo linings on brake shoes.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan35 | |
| Date | 1st May 1925 | |
| R.R. 493A (20H) (D.A. 652 20-3-24) J.H.D. EXPERIMENTAL REPORT. "-2-" Expl. No. 4214 1559 REF: Hal/C/G.5.25. With direct pressure on the front brakes we carried out a test on the Hispano to find which brakes were doing the work when the car was going backwards. We found that the rear brakes on that car, when going backwards, were more than twice as powerful than the front brakes. We have carried out tests with semi-flexible brake shoes. These were made in aluminium bronze, for convenience. With these we could obtain brake jaggers equally as bad as with the standard shoes. We tried removing the Ferodo on the forward end of the wrapping shoe. We had to remove 6" before jaggers could be produced. We have carried out tests with the standard shoes removing the Ferodo on the forward end of the wrapping shoe. Removing 1" at a time, we could produce jaggers with 5" removed the same amplitude and period as with the full ferodo. But with 6" removed, we could not produce any jaggers at all. We also carried out another test which appeared to indicate that jaggers were affected by the heel of the shoes as well as the forward end. We started off with a standard shoe which we could get to jagger badly. We left 4" on the toe and cut out the ferodo from 4" to 6" from the toe. We then carried on removing 2" at a time until we had a brake shoe which had 4" on the toe of the wrapping shoe, and 2" on the heel of the wrapping shoe. All the rest of the Ferodo had been removed. With this we could produce brake jaggers. When we removed the final 2" from the heel end of the shoe, the jaggers disappeared and also we could get no braking. contd... | ||