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).
Comparative analysis of automotive components, focusing on weight, materials, and design choices between different models.
| Identifier | ExFiles\Box 10\5\ 05-page067 | |
| Date | 3rd September 1937 | |
| -2- is almost exactly twice the weight of that of the Olds. Allowing for the fact that a pressed steel body gives some advantage, it is still clear that the Wraith frame has an altogether extravagant material-stiffness ratio, and we therefore believe that we are justified in following the Oldsmobile rather than the Wraith when going forward with Bentley III. designs. Furthermore, it seems clear that the gauge of material utilised on the B.III. frames already manufactured is unnecessarily heavy, and we are therefore going forward to find out where we can make it lighter without sacrificing efficiency. FRONT END SUSPENSION Basically, the engine weights being almost identical, the front wheels of the Oldsmobile ought to have only a little more weight to carry than those of the Wraith. The fact that the percentage is greater than it ought to be is mainly due to the unnecessary weight in the R.R. frame and front suspension parts themselves. Therefore, there can be no justification whatever for the Wraith parts being 73 lbs. heavier, particularly in view of the fact several pieces are in Aluminium on this assembly, whereas cast iron is used on the Oldsmobile. Regarding cost, it takes eleven pages to list the R.R. parts, three pages for the Oldsmobile, which is not quite fair because the latter's shock dampers are dealt with as units. However, we consider that the respective photographs alone justify us departing from Wraith practice on Bentley III, and we shall be dissatisfied if we finish up with more than 20% more parts than the Packard. REAR AXLE AND REAR END SUSPENSION It is perhaps fairer to compare the Bentley section with that of the Oldsmobile from the point of view of weight as these two cars have much the same load on the rear tyres. The Oldsmobile figure is 275 lbs, the Bentley 287 lbs. On the other hand, the Oldsmobile figure includes a roll rod, cast iron shock absorbers, no alum centre box and lower rating rear road springs and stiffer half shafts. continued | ||