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).
The strengthening of the Bensport Gearbox 1st and 3rd motion shafts.
| Identifier | ExFiles\Box 179b\1\ img161 | |
| Date | 16th November 1932 | |
| FROM HDY.{William Hardy} C. to GG. WOH. HS.{Lord Ernest Hives - Chair} R.{Sir Henry Royce} EH. HDY{William Hardy}1/M16.11.32. X4553. BENSPORT GEARBOX. STRENGTHENED 1st. & 3rd. MOTION SHAFTS. If the effect of the absence of radius on the fractured Phantom 3rd. motion shaft be ignored, a comparison of stress in 3rd. speed indicates the need for an increase in strength in the shaft shewn on N. sch. 3519, when the J.{Mr Johnson W.M.} 1. engine is used. From a consideration of maximum stresses only the shaft shewn on N. sch. 3519, is not disproportionate between front and rear ends, but we think that the occasional high stresses in the rear half of the shaft due to 1st. and 2nd. speeds are not so damaging as repeated shocks in 3rd. and top speeds due to lack of synchronisation of the engine when the clutch is engaged. The rear half of the shaft is in any case less stressed than some parts of the back axle. We note from BYX/0141132., that Derby have already increased this shaft, but so far we have received no print to inform us what has been done. We are therefore sending N. sch. 3590. herewith, which is in accordance with R's instructions, and enables an increase in the shaft diameter to be made without the introduction of features which R.{Sir Henry Royce} considers undesirable, such as: smaller pins for the cone than those shewn on N. sch. 3519, which are .187, pinning of the casehardened sleeve instead of retaining with a nut, or increased gear ratio for 1st. and 2nd. We also consider that a reduction in thickness of the hardened sleeve is undesirable. The diameter we shew for the front end is of course the same as that on the 20/25., but as the shaft is unbored on the Bensport the stress will only be 5% higher with the J.1. engine. HDY.{William Hardy} | ||