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).
Design modifications to an engine's aluminium extension, bolts, nose, and coupling for weight and cost reduction.
| Identifier | ExFiles\Box 42\1\ Scan140 | |
| Date | 26th February 1926 guessed | |
| (2) (4) ALUMINIUM EXTENSION. In addition to saving weight as referred to in section 3., by making the aluminium extension serve a double purpose this extension is now unsplit. The possibility of making this piece solid has been brought about by using a thread oil retainer in place of thrower. We judged that if the retainer on the Curtiss D.12. engine was sufficient for the purpose which is arranged thus then our method of application should be even more efficient, as Curtiss appeared to have no annular space for allowing the oil to get away freely in the upper half. (5) BOLTS. The number of bolts used for carrying the extension has been reduced from 9 to 6., and duralumin nuts used. (6) NOSE. There is a big saving in the aluminium nose as can be judged from the drawing, on which is indicated in chain line the previous nose designed by us. The saving over the one actually made and weighing 42 lbs. is even greater than indicated on the drawing, as the one made was arranged to suit the large dia. crankcase flange. (7) COUPLING. These parts have all been lightened to a small degree. A further slight gain in weight reduction might be made by dispensing with the centring disc and boring the nose casting to suit the crank but it appeared that the very slight gain was not commensurate with the inconvenience it would entail. We believe a considerable reduction in cost should follow from abandoning (a) split extension, (b) flanged steel bearing support and housing, (c) cellular construction at front end of aluminium nose, (d) fewer bolts, & (e) less material. A very small portion of this would be off-set by the addition of an oil retaining thread and the duralumin centring piece. We have not calculated the complete weight but immediately on receiving the individual weights from Derby of the unit weighing 42 lbs., we will forward the weight calculated. The writer considers it might be possible to gain some very slight advantage in weight reduction, and perhaps simplicity, by using a N.D. type bearing to take both thrust and journal load, and will proceed to investigate this proposition unless receiving any instructions to the contrary. AJS. | ||