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).
Test report on brake performance comparing aluminum and cast iron straps, clearances, and brake drum types.
| Identifier | ExFiles\Box 120\1\ scan0097 | |
| Date | 21th July 1932 | |
| -2- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}FD.{Frank Dodd - Bodies}21.7.32.Cont'd.{John DeLooze - Company Secretary} We found that the brakes were rubbing with the alum. straps after we had completed 49 brakes, whereas with the cast iron ones they were well clear. The reason for the brakes rubbing with still .25" clearance at the lever is, that the tip of the shoe C.W. type, gives this clearance when the brake pedal is compressed hard on. Our test shows that we lost a total of .75", this is the standard production setting on new cars and proves conclusively that this is insufficient clearance at the levers, for very fast road work. The difference between cast iron and alum. straps would mean another .5" movement at the lever, this is worth one inch pedal movement. A comparative test with plain brake drums fitted on the rear shows no change to the results obtained with the ribbed type. We are still conducting tests on the front brakes, but so far results indicate that these keep much cooler than the rear, probably due to the reduced braking, and a more exposed position to the wind stream. A report on these tests will follow later. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/F.Dodd. | ||