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, stiffness and failures of the Wraith side spare wheel carrier.
| Identifier | ExFiles\Box 114\3\ scan0222 | |
| Date | 2nd July 1937 | |
| 1013 To E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Les.{Ivan A. Leslie} c. Da.{Bernard Day - Chassis Design} c. E/Ev.{Ivan Evernden - coachwork} Rm{William Robotham - Chief Engineer}/Les.21/AP.2.7.37 WRAITH SIDE SPARE WHEEL CARRIER. The attached figures show the relative stiffness in the wheel carrier brackets from the frame on Wraith, Ph.III. and Bentley. The square section Bentley carrier in its light form is just over twice as stiff as the present Wraith carrier. Our figures also show that an attachment between the dash and the outside of the frame (X) reduces the deflection to about one half of the present deflection. A stay between the dash and the frame on the inside (Y) gives further stiffness, but is not nearly so important as the stay (x) on the outside of the frame. We should like to have a design for a square section Wraith carrier with a stay to the dash on the outside of the frame. As previously reported in our Rm{William Robotham - Chief Engineer}/Les.1/AP.3.4.37 the spare wheel carrier failed on the Bumper Chassis after 24 hours running. On the road it has been found that the spare wheel flap can be largely reduced by making the wheel a fit in the wing well. In fact we do not think there would be any criticism of the spare wheel movement if the wheels were made a tight fit in the well. We understand, however, that this is impossible due to metal spare wheel covers. Rm{William Robotham - Chief Engineer}/Les.{Ivan A. Leslie} | ||