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).
Springing tests conducted on the Spectre model to evaluate ride quality.
| Identifier | ExFiles\Box 95\3\ scan0074 | |
| Date | 26th March 1935 | |
| +346 Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux}9/KW.26.3.35. Springing Tests on the SpectreCodename for Phantom III. We have carried out springing tests at 30 m.p.h. on a broken surfaced road approximately one mile long. We repeatedly ran over this stretch of road to establish the effect of the springing in the rear seats. The riding qualities are not what could be called uncomfortable, but there is a jarring of the rear axle and a dithering sideways of the body. Our first test was to establish the value or otherwise of the torsion or control rod at this speed and road conditions. We therefore disconnected it from the axle, leaving the hydraulic dampers with minimum load in action. The result was a softer ride with less jarring of the axle. The dithering sideways of the body was still prominent. Our second test was to find what was the effect with the control rod only. The rod was connected up and the dampers disconnected. The result was more jarring of the axle than with the first test. The roll rod gave no damping effect and appeared to cause sharper jarring. Our third test was with the dampers and roll rod disconnected, the riding qualities being the rear springs only. The result was very little improvement upon the results obtained with the roll rod connected. The jarring of the rear axle was still prominent and the dither sideways of the body was just the same. The result of the last test proved that although the road springs should give a soft ride, considerable shocks are transmitted to the body by way of the anchorage of the springs to the frame, also the anchorage being held solid with the stiffened frame, the axle movement sideways is distinctly felt. The Cadillac people overcame this by mounting the front anchorage of the road springs in rubber blocks. This does two things: it allows the side movement of the axle to take place without the effect being transmitted to the frame, and also the jarring effect of the axle through the springs is damped out. The rear anchorage is more flexible and can be the usual metal bush. We are aware of what Leslie is doing, but in our opinion he has missed the vital damping point of view. | ||