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).
Results of road tests on Girling brakes fitted to a Bentley 1.B.LV.
| Identifier | ExFiles\Box 85\1\ scan0258 | |
| Date | 19th November 1936 | |
| 206 To E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c. to Ds. c. to Ev.{Ivan Evernden - coachwork} c. to Hdy.{William Hardy} c. to Hs.{Lord Ernest Hives - Chair} GIRLING BRAKES ON BENTLEY 1.B.LV. We have carried out the tests mentioned in your memo E.2/HP.14.11.36. (2) We have driven the car over some of the worst roads in the neighbourhood and we find that when the wheels go over pot holes the rubber buffers are compressed enough to allow the differential link pivot to hit the radiator fixing. The rubber absorbs the shock and no damage is done. The new axle, now arrived, may not allow this foul to occur. (6) We have connected the rear brake rope direct to the equaliser and no bad geometry effects are noticeable, i.e. the pedal does not 'pump' when braking on rough surfaces. The lever ratio which is altered by the omission of the idler lever, must be brought back to normal by alterations elsewhere, and the bijur system modified. (7) The gearbox crossmember certainly flexes a certain amount when the rear brake cable is removed and the brakes applied hard, but an adequate amount of front braking is obtained nevertheless. Additional stiffness of this cross-member will be an advantage. Incidentally, the minimum stopping distance of the car from 30 m.p.h. using the front brakes only is very closely the same as the stopping distance when using the hand brake only, but in the latter case much more effort is required to produce the same result. (8) The spring you mention in paragraph (8) is of very low rating and exerts a couple equivalent to 36 lbs-ins. on the cross shaft as detailed in R.R.Sch.1006. It would be advisable to make provision for slight adjustment of this couple, by instructing springs of various strengths, or in some other way. You will notice that in R.R.Sch.1006 provision is made for fitment of such a spring. We agree to all the modifications suggested but obviously they will take some time to carry out, and the next Bentley may go to France before this is done. The test will at any rate provide a durability figure for the Girling wedge. (5) As regards the rotating fork mentioned in paragraph (5) this is unnecessary if the rope is connected as in paragraph (6) Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||