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).
Vehicle roll testing, spring deflection, and wheel arch clearance for the Phantom and other models.
| Identifier | ExFiles\Box 14\8\ Scan165 | |
| Date | 5th September 1929 | |
| -2- Because of the 10,000 mile test results, in which no complaints have been made, and also because we know that there is less tendency for the body to roll at W.J. series than the Phantom, we believe that such a roll as indicated by the rolling test, and by swinging about the point B. can never take place on the road, because it would mean that the springs would be deflected sideways a matter of 1.5" each, and to provide such a deflection enormous forces would be called into play, and the spring fixings would be wrenched off the frame. Therefore the springs themselves prevent excessive rolling because they refuse to give way sideways after a certain amount. When looking at the Phantom however, we found that oscillating about the centre of suspension, namely point C, has almost the same effect as oscillating about the centre of one of the wheels, making a rolling test at the coachbuilders a feasible proposition. Since, therefore, the actual wheel arch clearance is a matter for experiment to determine, and now we see that our old empirical method of testing, namely by rolling, is no longer feasible, we would be glad if Ms. could examine the other experimental cars similar to the way we have treated 18-EX, namely, to measure the wheel arch and see whether it is up to the dimensions called for on our subframe print, and then see if any fouling has been indicated. After that we would like our new revised wheel arch tested as indicated in Da{Bernard Day - Chassis Design}/Evl/14.9.29. The conditions best for testing rolling seem to be those derived from running the car over rough fields at slow speeds, when the body pitches about the most. After these investigations and tests we are of the opinion that there should be no terrible risk in letting the first cars go out with the wheel arches as indicated on our subframe print, but if the slightly increased clearance suggested in our previous memo can be got on we think it would be wise, and a safe policy to have the arches modified. Da{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} | ||