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).
Claims for the benefits of a front roll rod and an appendix on Skid Pan testing methodology.
| Identifier | ExFiles\Box 9\7\ 07-page103 | |
| Date | 17th December 1937 | |
| -7- The claims for the front roll rod instead of the rear roll rod put forward include amongst other features, the following - (1) Produces a more stable car, particularly as regards directional stability on uneven surfaces and in strong winds. (2) Improves cornering ability and ease of handling, particularly near the limit of cornering speed. (3) Prevents dangerous rear skids when brakes are applied in emergencies or when turning sharply. (4) Is said to reduce both front and rear tyre wear, as it permits higher front tyre pressures, i.e., equal front and rear, and also reduces over-loading of rear tyres on corners. (5) Rear seat passengers are thrown sideways less. APPENDIX. Notes on the use of the Skid Pan. Throughout this report cornering power has been referred to in terms of decimals of G.{Mr Griffiths - Chief Accountant / Mr Gnapp} That is to say at 0.5G the total sideways force acting between the road and the tyres equals half the weight of the car. This force is a function of the radius of the turn and the square of the speed. It has been found that within normal limits, the steering characteristics remain the same whatever the radius of curvature of the turn. By thinking of a car as having so many degrees of under or over-steer at so many decimals of G we have a standard of comparison representative of any conditions. The steering angles given are measured by means of Autosyn motors, one attached between the track rod and the frame, and the other in the recording apparatus inside the car. Further tests scheduled for the future are to obtain steering angle curves plotted on actual steering wheel angle against sideways G.{Mr Griffiths - Chief Accountant / Mr Gnapp} A special steering wheel has been constructed which indicates the torque necessary at any cornering speed, and if these two results are compared with the steering angle curves as obtained by the present method an analysis of internal changes and deflections of the steering linkage will be possible. The angles of roll quoted in the report are also obtained on the skid pan by means of taking sights on the centre graduated pole, while rolling is actually taking place. | ||