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).
Stress analysis and comparison of rear axle options for the proposed B.80 Straight 8 engine.
| Identifier | ExFiles\Box 123\5\ scan0111 | |
| Date | 6th October 1938 | |
| GRY{Shadwell Grylls} what does "Century" Buick use. To By... from Da{Bernard Day - Chassis Design}/HB.{C. E. Harcombe} c. Da.{Bernard Day - Chassis Design} Rm.{William Robotham - Chief Engineer} De/Hdy.{William Hardy} Rm{William Robotham - Chief Engineer} Da{Bernard Day - Chassis Design}/HB.{C. E. Harcombe}21/N.6.10.38. 1044 Rear Axle for proposed B.80 Straight 8. ? file 202. Further to Da{Bernard Day - Chassis Design}/HB.{C. E. Harcombe}1/N.4.10.38, Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} has requested stress figures for Bentley axles with a ratio of 4.2 used in conjunction with the projected 5.7 litre 8 cylinder engine. It will be seen from the figures given below that the tooth loads per inch are considerably above anything we have had before, and are 60% above Messrs. Gleason's recommendation. This consideration alone would appear to rule out the use of an axle having a crown wheel diameter of 8.5". The pinion tooth stress with a .650 offset axle, 10/42 combination, is higher than on our standard axles, but not higher than Messrs.Gleason's recommendation. Tooth stresses for the .650 offset, 8/34 combination, and for the 1.5" offset axle, are below those on the standard Bentley and Phan.III. With the increased loads there is no doubt that apart from the above difficulty, both axles would have to be strengthened in various places and fitted with more substantial bearings. 8 cyl. engine (3½ x 4½) Max. torque. 3200 lb.ins Dia. of crown wheel 8.5" Offset. .650 .650 1.500 1.500 Combination. 10/42 8/34 10/42 8/34 Ratio. 4.2 4.25 4.2 4.25 Max.pinion stress direct drive lb.sq.in. 34000 25700 20600 14400 Load/in. face on gear teeth lb. 2660 2690 2530 2560 Da{Bernard Day - Chassis Design}/HB.{C. E. Harcombe} | ||