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).
Issue of brakes pulling on the B.V. series cars and proposed modifications.
| Identifier | ExFiles\Box 98\3\ scan0073 | |
| Date | 23th January 1939 | |
| H06 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/DB.{Donald Bastow - Suspensions} c. Rm{William Robotham - Chief Engineer}/EJH. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}5/MH.{M. Huckerby}23.1.39. BRAKES PULLING - B.V. SERIES. We would like to build a B.V. type car with hydraulic front brakes and much less out-of-centre transverse offset, reduced by increasing transverse lean. We attach a graph showing the variations in co-efficient of friction obtained from a piece of lining heated up to the moderate temperature of 200°C three times. At any given temperature the coefficient of friction is not definite. As long as there is transverse offset, no matter how perfect the front equalizer, there will be a tendency for brakes to pull the car to the side, as both front brakes can hardly ever pull equally. With hydraulic brakes the transverse lean does not affect the brake linkage. Da{Bernard Day - Chassis Design}/DB.{Donald Bastow - Suspensions} points out that increase of transverse lean makes the steering heavier because it raises the car, but this is immediately reduced by the decrease of out of centre. He further points out that in fixed axle days, transverse offset tended to neutralize gyroscopic joggles, but that we have reduced gyroscopic effects on independent suspension without reducing offset. There is, therefore, no reason to suppose that any very pronounced change will be apparent on the steering, except, possibly, that it may become heavier for shunting due to lack of rolling action. As this modification necessitates a new pivot, Rm.{William Robotham - Chief Engineer} would like to try a castor experiment at the same time, which he has already explained. This second modification consists of increasing the castor angle but retaining the present (+¼°) castor offset. We would like a pivot designing and making for fitment to one of the hydraulically braked cars. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||