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).
Technical memorandum discussing the pros and cons of banjo type back axles compared to existing designs.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan170 | |
| Date | 7th May 1931 | |
| ~~HY.{Tom Haldenby - Plant Engineer} RHC.{R. H. Coverley - Production Engineer}) FROM R.{Sir Henry Royce}~~ ~~HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} )~~ ~~Copy to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager}~~ ~~Copy to DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer}~~ ORIGINAL R3/M7.5.31. x7350 x s-350 BACK AXLES. I am quite in agreement that the banjo type axle (WHICH WAS ACTUALLY DRAWN FOR "PEREGRINE") has several advantages, and noticed long ago that the gears could be assembled as a unit and put in the axle, and also one can now see that in our numbers it may be less costly for materials, though on the face of it this would not appear great. Ford has an axle comparable with ours (i.e. not banjo.) Our present 20HP. is 11 yrs. old and I understand the tubes are not made as intended but are machined from enormously heavy forgings. Our 40/50, (and 25HP. hypoid) are made very differently to the 20HP., and if the tubes were made by the <u>tube people to size</u> they should not be costly or need much machining. There is nothing difficult about them compared with the most up-to-date banjo forging - see Rubery Owen (Scott patent.) Originally we thought our axle had the following merits: (1) It permitted the largest bevel wheel for its depth. (2) It built up squarely and centrally, driving shafts would be happy. (3) It made a stronger job because the shape and materials could be better than the soft pressing welded with doubtful joints. To compare with the banjo for cost we could weld our tubes from half pressings in sheet metal, which we would not do to save money, shewing how our tubes fundamentally are not costly. We have had very little axle trouble during over 25 yrs. where-as we hear that Bentley and Invicta, and many others, are not happy (see Bentley's enormous 4 litre. B.A) Finally we have <u>not time at the moment</u> to give to <u>changing</u> <u>this</u> as we have a good axle tested over 10,000 miles and passed, and we have other work far more vital, but I quite agree that if we were starting we might find the banjo good enough - more convenient, somewhat cheaper under our conditions, but not <u>better</u>, <u>stronger</u>, or <u>lighter</u>, and not <u>really extravagant</u> - see Ford. (Handwritten below 'lighter, and not'): WE ARE R.{Sir Henry Royce} | ||