Inadequate bending stiffness of the Wraith III front suspension front pan and proposed modifications.
| Identifier | ExFiles\Box 9\5\ 05-page049 | |
| Date | 8th April 1937 | |
| SECRET To EY. Copy to Ds. Rm. {William Robotham - Chief Engineer} RHO. HFS. My/Les. RHC {R. H. Coverley - Production Engineer} /TVI. Wraith III Front Suspension Front Pan. The Expl. Dept. have told us that the vertical bending stiffness of the front pan of the front suspension on Wraith II was inadequate, and that the frame side members open and shut on the bump chassis, whilst on jacking under the front pan the dimension between the top of the frame side members increased by .120" as against a corresponding figure for Phantom III of .090". It is possible that this frame movement explains the failure on the bump chassis of the following:- 1) The attachment of the frame extension to the main forging. 2) The bonnet rest plate to the radiator. 3) The front engine foot bracket on the frame. 4) The side spare wheel carrier. 5) Dashboard attachment. Although we understood the pan as originally designed could be made with reasonable ease, we now learn that this is not the case, and we are therefore sending herewith N.Sch.5105 which shows a simplified and stiffened pan. The top pressing of the pan is unaltered with the exception of the introduction of some finger grooves. The lower closing member of the pan is a flat plate having finger grooves. The thickness of the material of the pan is .080". To save weight a sheet metal bridge piece spot-welded into the pan in conjunction with a simple aluminium die casting takes the place of the forged stiffeners in the pan at the attachment to the main forging. To give the pan bending stiffness to resist the load of central jacking a die casting is inserted at the pan centre supplied by us but fitted up by the maker of the pan. Long bolts hold on the central steering lever bearing housing and the jack pad, the drilling for which it is intended should be done by ourselves on a jig. The change from square headed bolts to hexagon headed bolts has necessitated modifications to the central steering | ||
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).