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).
B.III rear axle, recommending a larger 3-row pinion bearing and outlining mounting conclusions.
| Identifier | ExFiles\Box 98\1\ scan0130 | |
| Date | 16th September 1938 | |
| 402 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. Da.{Bernard Day - Chassis Design} c. Hdy.{William Hardy} c. Ev.{Ivan Evernden - coachwork} c. By/CRL.{C. R. Lisson} Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}2/MH.{M. Huckerby}16.9.38. B.III REAR AXLE. In view of the decision to use a fully floating rear axle for the first few series of B.III's we recommend that we remove all doubt about the adequacy of the pinion bearing by going to the larger 3 row variety. This means a modified centre casing. We have discussed with Hdy.{William Hardy} the best mounting for this bearing and have come to the following conclusions:- (1) Single piece inner race as on PD.40. (2) Preload by the securing studs and not a separate nut. (3) Oil feed through grooves in the thrust outer as on B.II. (4) Oil retained by a thread and not a seal. Although we know that the modified two row bearing on the last half of 'M' series is an improvement, dynamometer tests show the 3 row bearing of the semi-floating axle to be considerably better. A drawing is required from the Design Dept. as soon as possible so that tests can start on dynamometer and road to prove the arrangement recommended. Should the 3 row bearing give some unforseen trouble we can continue as on 'M' series. The axle gears should be 10/41 ratio which with 6 1/2 x 16 tyres will give at 4500 engine r.p.m. 91 m.p.h. on direct and 108 on overdrive. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||