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).
Report comparing the steering of a 3-Litre Sunbeam car to a Phantom chassis, analysing the effects of front axle weight and suspension.
| Identifier | ExFiles\Box 24\1\ Scan020 | |
| Date | 27th April 1926 | |
| W/S. To Bt.{Capt. J. S. Burt - Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. c. to CMB. c. to FN. A E DaWOR X446 Hs{Lord Ernest Hives - Chair}/Rml/LG27.4.26. 3-LITRE SUNBEAM CAR. X8430 BT{Capt. J. S. Burt - Engineer}3/GN26.3.26. With reference to the very interesting report on the steering of this car. We consider the reason why this steering is so light for shunting purposes is because the total chassis weight is less than 25 cwts. and the steering gear ratio is approximately the same as on our 38 cwts. chassis. We have established conclusively that the weight over the front axle of the car is the main factor in determining ease of steering at slow speeds. We have in the Experimental Dept. a very good example of the effect of taking a small quantity of weight off the front of the car. On 10-EX, a new PhantomCodename for PHANTOM I chassis fitted with an exceptionally light sporting body, the weight on the front axle when the car is loaded with passengers is 23 cwts. the steering is quite pleasantly light to handle under all conditions. On 44-PK however, which is another Phantom chassis fitted with a large Limousine body, the front axle weight is 26¾ cwts. when loaded. The steering on this car is very different from 10-EX, being noticeably heavier when shunting. Steering at high speeds is very largely a matter of the suspension and weight distribution of the car. Flexible springs and low pressure tyres on the front axle, whilst giving comfort at normal touring speeds, undoubtedly tend to reduce the selectiveness of the steering at the higher speeds. In addition, flexible rear springs and a high centre of gravity, such as is found on most Phantom cars, (owing to large ground clearance and closed bodies) undoubtedly tend to give the impression of instability due to a certain amount of side sway when leaving the crown of the road to pass another vehicle. In order that the nature of the present compromise in the Phantom steering may best be appreciated, we have enumerated a few of the fundamental principles in question in a forthcoming memo. We hope that these will be borne in mind when comparing the Phantom steering with that of any other make of car built for one specific purpose only (such as high speeds) as in the case of the 3-litre Sunbeam. Hs{Lord Ernest Hives - Chair}/W. A.{Mr Adams} Robotham. | ||