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).
Technical analysis and comparison of various vehicle suspension systems, with requirements for a rationalised programme.
| Identifier | ExFiles\Box 154a\2\ scan0055 | |
| Date | 27th March 1939 guessed | |
| -3- (D) The bending of the yoke etc makes an initial set up for deflection necessary (.375 at torque arm sphere). We have not heard of any measurements being made of the torsional and transverse bending deflections of the yoke and their effect on the steering, which would be similar to that of the rubber bearings - see (C). (E) The wheel movement is limited to 5.750 ins. as against 8" on Wraith III. This appears to be scarcely enough for B.5. as reports ask for softer rubbers which we cannot provide with so limited a travel. Whether such a small wheel movement would be suitable for Wraith 80 is very doubtful. (F) The design layout of a Packard suspension has greater limitations than either wishbone, torsion bar or Dubonnet. The torque arm is the culprit. If its rear bearing is under the frame, the frame sidemember depth is limited to a figure of 4½" on B.5. If it is outside of the frame, the torque arm will foul the tyre unless the track is increased materially. The frame cannot be narrowed. These troubles do not obtain to the same extent if the car is 5 ins. higher and has an American front. Of the original advantages of this suspension numbers (1) and (4) above remain in full, and (2) remains in a measure. If we were asked to choose a suspension for the rationalised programme, it would have to satisfy the following requirements in particular:- (d) Have the lightest pieces, and no waste metal. (e) Have at least the wheel movements of Wraith III. (f) Cause the frame to be subjected to the minimum torsion, since we cannot be sure of, or use the body rigidity to the full, neither do we want to use a big frame cross. (g) Have flexibility between the suspension and the frame to reduce noise transmission. Cont'd... | ||