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).
Proposal for lightening the Phantom front axle by milling it down to the original drawing dimensions.
| Identifier | ExFiles\Box 67\2\ scan0172 | |
| Date | 26th September 1925 | |
| To BY.{R.W. Bailey - Chief Engineer} from DA.{Bernard Day - Chassis Design} c. to CJ. Hs.{Lord Ernest Hives - Chair} H8x20 DA{Bernard Day - Chassis Design}1/M26.9.25. X.8420 X.8940a LIGHTENING OF PHANTOM FRONT AXLE FOR CAR GOING TO FRANCE. We are sending you today an N.s.ch. shewing what Mr. Royce proposes should be done with the existing axle parts to reduce weight. With reference to the axle forging itself we have measured as far as we are able the section of the forging which Hs.{Lord Ernest Hives - Chair} brought down here, and we find that it is enormously heavier than either our original design or the Derby detail drawing, which closely follow one another. As far as we can measure the cross section, not a single dimension is correct, and by setting out the two sections on the board and taking the area with a planimeter, the actual forging is 158% of the weight it should be. Speaking roughly this represents an increase of something just over 20 lbs. which in a weight of 62 lbs. in a very great difference i.e., it is 62 lbs. instead of 42 lbs. It would appear that the first thing to do is to get the axle forging back to the drawing dimensions. As an approximate way of doing this we propose that the top and bottom flanges of the axle should be milled on the outside until the total depth of the axle is 2.625. The milling cutter would run the whole length of the axle, missing of course the spring pads, brake shaft, carrier bosses, etc. We estimate the saving would be between 7 to 8 lbs. A further move is to run a milling cutter along the central web in the part between the spring pads. As this central web is very much thicker than the drawing, and as the flanges also are thicker, quite a good weight can be taken out like this. We then suggest that the bosses for the shock absorbers, and also those for the brake shaft brackets, should be reduced to drawing size by milling. We should like you to go into the question of these machining operations on the axle, and if you agree machine one for the purpose of bumping and another for the car going to France. DA.{Bernard Day - Chassis Design} | ||