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).
Experimental progress report on a 40/50 car's 4-wheel brakes during a road test.
| Identifier | ExFiles\Box 30\6\ Scan152 | |
| Date | 17th January 1924 | |
| R.R. 403A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} (Le CanadelHenry Royce's French residence) 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} Expl. No. 9940 1559 REF: Hs{Lord Ernest Hives - Chair}4/LG17.1.24. SECRET. BRAKES+ PROGRESS REPORT We are running a 40/50 car on the road with 4-wheel brakes 16 hours daily. The car runs about 360 miles per day. The object is an intensive road test on brakes so that the actual number of road miles on this test is not very important. The route is over the Derbyshire peak district. The drivers are using these their brakes as much as possible but they do not apply the brakes with any power on. The car has now completed 1,000 miles. We should estimate that this is equal to 4,000 miles of average conditions. The rear brakes are the present standard - the front brakes are the original type with solid shoes. We have not found the temporary jointed shoes very satisfactory. We have not yet had a test of any of the designed jointed shoes. The servo leverage is reduced as explained in our memo. Hs{Lord Ernest Hives - Chair}4/LG11.1.24. Tests on the car before it started this test proved that the braking was fairly equal. At 20 m.p.h. we could pull up in 29 ft. - at 30 m.p.h. we could pull up in 51 ft. During this 1,000 miles run the servo adjustment has been taken up 40 notches in order to restore it to its original setting. This is equal to a wear of approx. .060" off each shoe. When we are working with light pressure on the servo the wear is considerably more than on any of the other brakes. At the start of the test the front braking was even and the steering was affected by the braking. After 300 miles contd:- | ||