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).
Analysis of steering characteristics for the Wraith model, with a corresponding steering angle curve graph.
| Identifier | ExFiles\Box 9\7\ 07-page098 | |
| Date | 17th December 1937 | |
| -2- This peculiarity of the steering was confirmed by tests on the skid pan and steering angle curves were taken on various Wraith cars both with the 1.5° and the ¾° castor angle. A curve was also taken of 25.U.VI with raised rear springs for reducing sideways shake of the rear axle. None of these differences affected the general characteristics complained of and the curve below is typical of all the cars tested. [Graph text begins] TYPICAL STEERING ANGLE CURVE FOR WRAITH TYRE PRESSURES REAR 30 lb/sq" FRONT 25 lb/sq" Y-Axis: UNDERSTEER 1/2°, OVERSTEER 1/2° X-Axis: SIDEWAYS G.{Mr Griffiths - Chief Accountant / Mr Gnapp} FIG 1 [Graph text ends] FIG. 1. It was clear from this that at the point where the curve turns over the cornering power of the rear wheels had suddenly fallen, which indicated that the outside rear tyre was being overloaded. The probable cause of this was that the major resistance to roll was at the rear of the car. The rear and front roll ratings were measured on the weigh bridges and it was found that the rear was in fact far in excess of the front, namely 228 lbs/inch and 107 lbs/in respectively. The rear was reduced to 162 lbs/in. by | ||