Secret memo detailing weight-saving modifications for the Wraith III front suspension main forging.
| Identifier | ExFiles\Box 9\5\ 05-page047 | |
| Date | 8th April 1937 | |
| SECRET. To EY. Copy to Dr. Rm. {William Robotham - Chief Engineer} RHC. {R. H. Coverley - Production Engineer} HPS. {Horace Percy Smith - Experimental Factory Mgr} Rm {William Robotham - Chief Engineer} /Lee. RHC {R. H. Coverley - Production Engineer} /TVI. E {Mr Elliott - Chief Engineer} /Ev. {Ivan Evernden - coachwork} 1/IN.8.4.37. 646 Wraith III Front Suspension Main Forging. We have already sent to you N.Sch.5018 showing the modification to the front suspension main forging for removing the considerable amount of excessive metal. On examining the fully machined forging further in conjunction with HPS. {Horace Percy Smith - Experimental Factory Mgr} we have considered that a further 4 or 5 lbs. of weight could be saved, and our final proposals are shown herewith on N.Sch.5106. These modifications call for a new die, but for the first cars it is possible to machine the proposed new design from the original forgings, and we suggest that this policy should be adopted. In this manner HPS. {Horace Percy Smith - Experimental Factory Mgr} hopes to get this revised design on the first Wraith III. The modifications consist of the following:- 1) The reduction of metal at the junction between the frame attachment and the main forging banjo already shown on N.Sch.5018. 2) The reduction in size of the bolt bosses as they were left large in the original design to allow for drilling in position. We now understand from RHC {R. H. Coverley - Production Engineer} /TVI that it is proposed to jig drill both the frame and the forging and only ream in position. 3) The thickness of the flanges on the portion extending into the frame has been reduced, and their width tapped from the main forging down to the last frame attachment bolt boss. 4) The thickness of the face carrying the studs holding on the spring pot has been reduced. Standard studs are used, the drilling for which breaks through. In order to prevent oil leaks we suggest that the studs be inserted with red lead or some other suitable compound. 5) The same remark as in No.4 applies to the inner face of the forging. 6) Six bolts, instead of five, are used for attaching the forging to the pan and this has enabled us to remove considerable metal in this vicinity. | ||
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).