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).
The testing of an experimental passenger car steering system fitted to a Buick and a discussion of ideal steering ratios.
| Identifier | ExFiles\Box 154\3\ scan0047 | |
| Date | 24th October 1927 guessed | |
| 2 Control of large valves in power stations Steering gears for commercial vehicles, tanks, and large tractors. Passenger cars. PASSENGER CAR STEERING Mr. Nieman loaned us his Buick car, fitted with this steering experimentally, and four of us, including Mr. Nadin and myself, drove it perhaps 8 miles over roads which we know are trying to the average steering. Unfortunately, the old Buick has a very poor steering, irreversible or nearly so, and of high ratio (about 15 to 1) and the amplification is admittedly too high (about 10 to 1), so that it is scarcely a fair test of what may be expected. However, even under these conditions we were all profoundly impressed by the possibilities of the steering. (1) The car could be steered when rolling (though with difficulty) with the engine dead, so that in the event of an accident the car could be towed home. (2) With the engine running the car could be steered under any conditions including standing-still, with two fingers on the wheel. (3) There was no sense of anything but the ordinary mechanism between steering wheel and road wheels; the front wheels followed the steering wheel accurately and without backlash or time-lag. (4) On the roughest road there was no appreciable steering reaction at the wheel. (5) The steering was really too easy for comfort and the lack of self-centring made it tend to wander at speed. Even so however, it was better than many modern balloon-tyre steerings of 20 to 1 ratio. (6) Because of the ease of steering, it would be possible to give instant full lock at speed, and turn a car over. (7) For parking it was of course ideal. DISCUSSION. Mr. Nieman admitted the faults and points out that the device has been made by inserting an amplifier-unit in the original steering gear, (first reducing the amplification to 10 to 1) whereas the entire steering should really be redesigned. The ideal would be (he thinks) a steering ratio between 5 to 1 and 9 to 1, and a power amplification of say 5 to 1. This would be equal to a 25 to 1 or 45 to 1 ratio in parking and give the sensitive control of a 5 or 9 to 1 ratio at speed, but without appreciable road-reactions. The steering gear itself need have no effect of irreversibility, for example, a plain bevel and sector could be ideal if the backlash were eliminated. The amplifier itself in reverse is an accurate device for limiting shock to the hands, for example with a 5 to 1 bevel ratio and 5 to 1 amplification the reverse torque at the steering wheel is always 1/25th of the torque at the front wheels. If there is sufficient pivot lean etc. and not too much friction, in the hand operated portion of the column, the steering will self center, (Continued) | ||