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).
The performance of Bentley brakes, addressing overload claims, test runs, and potential improvements.
| Identifier | ExFiles\Box 85\1\ scan0047 | |
| Date | 16th March 1936 | |
| x206 Rm{William Robotham - Chief Engineer} MARTINDALE Sg.{Arthur F. Sidgreaves - MD} from E.{Mr Elliott - Chief Engineer} E.1/HP.16.3.36. C. Wor.{Arthur Wormald - General Works Manager} Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} Ds. RHC.{R. H. Coverley - Production Engineer} re Bentley Brakes. Referring to Sg.{Arthur F. Sidgreaves - MD}9/E.9.3.36, if we accept the statement that the 4 1/4 litre Bentley brakes are overloaded then production should not go on. Personally I think this is an overstatement of the position. We are aware that we can overload the brakes under certain conditions, but so can we also every other part of the car, and we do not refuse to send out Bentley engines because we can break them up on the test bed. I will agree that we have not got the margin we should like on the brakes in view of the increased ACCELERATION with the larger engine. The sort of treatment which shows up fading is exceptional. The run which we have to the Royal Red Gate consisting of 28 miles of extremely twisty road usually carrying no traffic is exceptional, and to accomplish this in 35 minutes means averaging 48 miles per hour, and using the gearbox for acceleration. W.O. Bentley used to claim to do this 28 miles in 28 minutes, and as there is one town, a number of villages, and three humped back bridges en route, as well as Derby to get out of, it means driving in a manner which very few people would adopt. It is true that Staniland was reported to have brake fade on this stretch, but only by driving right up to the limit of the car remaining on the road. I, therefore, think that we ought not to be unduly alarmed, but have been looking round for some more easily available improvement than completely changing our brake drum technique as with the use of aluminium Two experiments that have been tried are the millenite brake drum with cast helical ribs, and the use of sheet metal fan blades welded to the back plate of the drum. The former although it has given very good results is not very practicable from a production point of view. | ||