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).
New front axle and brake design, with improvements over the existing 25HP model.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan061 | |
| Date | 18th March 1931 | |
| SECRET ORIGINAL DA{Bernard Day - Chassis Design}1/M18.3.31. y5420 x5421 R.{Sir Henry Royce} FROM DA.{Bernard Day - Chassis Design} C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} (struck through) C. to HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} HY.{Tom Haldenby - Plant Engineer} J.{Mr Johnson W.M.} 3. FRONT AXLE & BRAKES. Attached are prints of N. schs. 3246. 3247. & 3254., dealing with the new front axle dropped .750 lower than the 25HP., which is a development of N. sch. 2738. sent to Derby some time ago but not proceeded with. The objects are to give room for more flexible front springs, to provide an attachment for axle control, and to enable more braking surface to be obtained, and to economise as far as possible on the axle fittings as compared with the existing 25HP. The steering geometry is also improved. With .750 increased drop the ground clearance is still 9". The increased offset and general lines follow the Phantom axle. The brake dia. has not been increased but by widening the shoes as shewn the brake lining area is so increased as to have a margin over all the cars quoted against us by HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer}, except Mercedes which has an exceptionally large area. On the 25HP. the front brakes are definitely small in area compared with P. 2. or other cars. If we did, increase the dia. to 14" we could then use exactly the same shoes as on the rear foot brake, with resulting economy, but we were rather afraid of the increased weight on the front axle. There would be a great saving (we are instructed) by using Rudge-Whitworth instead of Dunlop wheels, and we have made N. sch. 3254. shewing the application of a R.W. wheel to this axle. As now usually arranged the R.W. hub cap projects beyond the centreline of the wheel about an inch more than the best that can be done with the Dunlop. On N. sch. 3254. we have shewn a slight re-arrangement of the spokes and locking device to enable the overhang to be the same as with Dunlops. We have to do the spring loaded ball ends for both cross and side steering tubes with reduced loading per square inch, and have shewn preliminarily some larger ball ends, but the schemes will follow. Prints of N. schs. 3246/47/54. also attached to BY's copy of this memo. DA.{Bernard Day - Chassis Design} | ||