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).
Technical memo proposing modifications to Bentley brake systems, including thicker linings and adjustments to the servo mechanism.
| Identifier | ExFiles\Box 84\2\ scan0046 | |
| Date | 13th July 1933 | |
| X206.. To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. Da.{Bernard Day - Chassis Design} By.{R.W. Bailey - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}1/KT.13.7.33. BENTLEY BRAKES. We wish to incorporate on the second series of cars thicker linings .375" instead of .312" and 14.1/8" dia. front drums, and 12.1/8" rear drums. We suggest keeping the angular adjustment the same and increasing the cam radius to .444 to use the extra lining. Possibly the screw adjustment will have to be finer. The present direct brake ratio is 29 which we wish to reduce to 23. We know from the 20/25 that we can then have a ratio of servo braking of 18. The pedal will then reach the boards before the servo hits its stop. We can then divide the servo movement up equally between the front and rear brakes obtaining the required greater servo braking to the front by virtue of the larger drum. We attach a suggested lay-out showing the three new levers required. At servo multiplication of 2.3 found experimentally on 4.B.IV. chassis, we have 45.5% front braking in comparison with 46.5% on the present chassis. Although it seems unusual to have larger front drums that the rear drums, we think it will be a great advantage to have an equal multiplication from the servo to front and rear with consequently no movement of the swinging arm. Even if the brakes do not wear at the same speed, the movement of the swinging arm will be smaller than it is now and thumps should not trouble us at all. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||