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).
Experiments carried out to overcome Bentley brake judder.
| Identifier | ExFiles\Box 84\2\ scan0111 | |
| Date | 28th February 1934 | |
| X206 To Sg.{Arthur F. Sidgreaves - MD} from Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c.c. to OF. c.c. to EV.{Ivan Evernden - coachwork} c.c. to EV.{Ivan Evernden - coachwork} c.c. to DA.{Bernard Day - Chassis Design} c.c. to Hdy.{William Hardy} c.c. to LV. c.c. to Em. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}1/KB.28.2.34. BENTLEY BRAKE JUDDERS. We have now carried out a considerable number of experiments to overcome this trouble. With no scheme applicable to existing Cars have we been able to effect a complete cure. We discovered, however, during the experiments that the inertia of the cycle type wings on the Streamline Car prevents the judder. On removing the wings a judder was apparent, and on replacing them the brakes again could not be made to judder. The experiments carried out with no beneficial result are :- (1) Chamfering the leading edge of the wrapping pilot shoe. (2) Removal of the wrapping pilot shoe; nor did this affect the inefficiency of the brakes suggested as possible in Lys./T.18.2.34. (3) Saw cutting across the cooling ribs every 2" (16 cuts). This doubled the diametral expansion of the drum in a horizontal plane for a given load and also doubled the sponge measured on the last actuating lever. (4) Machining off all the cooling ribs, which trebled the flexibility and sponge. It was very noticeable that the front brakes ran considerably hotter than usual, emitting smoke after one stop from high speeds. (5) Fitting bonded asbestos linings (standard or 4./30). (6) Water exclusion baffle, H.Sch.3973 (see separate report). (7) Taking all the slack out of the two bearings supporting the toggle actuating shaft. | ||