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).
Test report on frame jellying and steering for the Phantom II model.
| Identifier | ExFiles\Box 28\5\ Scan052 | |
| Date | 1st April 1931 | |
| FOR FILES. 8457. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1.4.31. X7380. FRAME JELLYING AND STEERING TESTS PHANTOM 11. Tests were carried out on the Ashbourne - Buxton Road with three cars - 27-EX. Four sandwich engine feet and std. front springs. 20-EX. Sandwich feet and low rating front springs. 22-EX. Std. front springs Diabolo rubber feet and frame side members twice the standard thickness. The first test carried out was to determine the effect of removing the rear engine feet on 20-EX. The tyres were run at 35 lbs/sq.in. With all four engine feet the jellying of this car was bad but not exceptionally so. The steering shocks were excessive considering the road surface on which the car was tested was not very bad. The worse period of jellying and road shocks was at 65 - 68 m.p.h. The rear engine feet were then removed on this car and the test repeated. The selectivity of the steering appeared to be slightly worse, the road shocks worse when of large amplitude but possibly the small amplitude shocks were not quite so frequent. On the whole the difference between four and two engine feet was much less then we expected. 22-EX. with four Diabolo feet. The steering of this car was markedly better for road shocks than for selectivity The amplitude of jellying appeared to be no more than 50% of that on 20-EX. This car was fitted with centre point radiator mounting which was tightened up solid after the first run. It was noticeable that the wings and lamps seemed to oscillate slightly more when the radiator was single point mounted than when it was tightened up. We do not think that anyone would be justified in complaining about the steering of 22-EX. The next step is to fit this car with the low rating front springs and again compare it with 20-EX. to see if the difference between the two cars can be ascribed to the heavier frame or to the fact that one car was fitted with lower rating front springs and the other with standard front springs. During the comparison of these two cars 20-EX. car was tried with tyres at 45 lbs/sq.in. In this case jellying and road shocks were both noticeably less than when run at 35 lbs/sq.in. 27-EX. This car was tried for steering and jellying with four sandwich engine feet. The steering shocks and radiator movement were very similar to those obtained on 22-EX. The jellying was not excessive. Selectivity of the steering was very poor without any Hartfords. Tightening up the Hartfords greatly reduced the steering shocks and improved the selectivity. | ||