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).
Steering tests for the 'Spectre' model, comparing its performance with a Cadillac and analysing the impact of different steering boxes, suspension, and tyre setups.
| Identifier | ExFiles\Box 17\4\ Scan097 | |
| Date | 10th December 1934 | |
| Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}20/KW.10.12.34. SpectreCodename for Phantom III Steering. We have now carried out a number of tests on the steering on this car. These tests in conjunction with those on 27-EX have enabled us to come to certain conclusions as to the relative merits of the Cadillac and parallel motion suspensions. The most noticeable feature of both cars and also the Cadillac is that it is not only possible but safe to drive at high speeds with no front damping, thereby securing a better rear seat ride. Before we made any other alterations to spoil the Cadillac steering we found that there were no road shocks even with no front damping. We have aimed at attaining this on the SpectreCodename for Phantom III. Apart therefore from when it is stated to the contrary, all tests on the SpectreCodename for Phantom III refer to conditions of minimum damping. The car as originally built to an exact copy of the Cadillac except for the R.R. steering box suffered from continuous road shocks far worse than the standard 40/50. We checked over all likely differences such as pivot lean and wheel angle etc., but could find no differences to account for the shocks. On fitting a La{L. A. Archer} Salle steering box the shocks almost entirely disappeared, but began to make themselves noticeable after about a month's running, never of course comparable with the original results. We had two different tyre sizes to try, 7" and 7½" section. The smaller the tyre and the higher the pressure, the less the shocks, but we can say that a customer would not notice the difference which is a relief after being used to the 40/50 road shocks which are so sensitive to lower tyre pressures. The wings and radiator on this car being centre mounted are quite steady. We therefore fitted a triangle on the frame extending above the radiator, and could then notice a small amount of frame movement but far less than on a Phantom. | ||