SENSATION OF FLOATING ON AIR

Wanganui Chronicle, Volume 71, Issue 177, 28 July 1928, Page 21 (Supplement)

SENSATION OF FLOATING ON AIR

FRONT WHEEL DRIVE OR FOUR WHEEL SPRINGING CHANGES MAY TAKE PLACE SIMULTANEOUSLY. (From our London Correspondent). It is a matter of opinion whether, in the further development of motor-car design, iront wheel drive or four wheel spring suspension will be first adopted. Possobiy both will move together, if only because front wheel drive involves the necessity to redesign the chassis, in which case it is almost as simple to provide each wheel with independent spring suspension as to adapt the present system of axle springing. Four wheel suspension, ,1 may explain, is the provision of each road wheel with a spring or springs which will allow it to react under road shocks independently of the other three wheels. I had a recent test of a machine so fitted, and my experience has convinced me that its inherent comfort, not to say luxury, can scarcely fail to compel its ultimate adoption. Previously 1 had knowledge of a couple of cars on which the front wheels only had separate suspension and they were very steady and comfortable on badly broken surfaces, but undoubtedly the application of the principal to all four wheels is an improvement on that. On a relatively small car with a restricted wheel base, one has the sensation of floating to a degree, comparable with ordinary suspension well loaded and allied to an abnormally long wheel base. Pitching is minimised, rolling is absent, and I imagine that four wheel springing should do much to prevent skidding on bad surfaces. The first car on which, individual spring suspension of front wheels was exploited, 1 think, was the old single cylinder Sizaire Naudin. Later the Lancia Lambda embodied it and now the Cottin-Desgouttes has all four wheels separately sprung. It might be thought that there must necessarily be some sense of flabbiness in handling a car so sprung, but although I looked I for it I could not discover any other I difference from the orthodox type than I the sensation of floating to which I have alluded. The steering was light but quite steady, and the rear drive, apparently was as firm and efficient as any other car I have travelled in. Of course there are no “through” axles. The front wheel suspension is arrived at by employing a single inverted semi-elliptical tranversc spring anchored at its centre to the front member of the chassis frame and shackled at its ends to brackets which carry the steering pivots. These have pillars prolonged upwards into air cylinders which are attached to the outer ends of the front member of 4 he chassis frame, and between the latter and the ends of the transverse spring are encased in heavy spiral springs, the result being a combination of air and spring cushion suspension. The range of vertical movement in cadi wheel is about seven inches, but so far as I could judge it very seldom extended in practice to more than half that. Obviously steering control has to be specially devised and, in this instance, it is duplicated, a separate arm and drag link being provided for each wheel.

The rear axle lay out is simple but ingenious. The driving wheels are carried on stub axles borne by rectangular plates, those plates are linked an to each other by four inverted semicliiptical springs slightly cambered, which are shackled to the four corners of the stub axle plates to form a girder of sorts. Between the upper and lower pair of these transverse springs, and at their centre, is the differential easing in a box to which the transverse springs are bolted, and the box in turn is bolted to the rear member of the chassis frame at its centre. The drive from Ihe differential to the road wheels is taken by a pair of universally jointed shafts after the manner of the earlv De Dions.

The only real objections T could discover at the moment wore the increased chassis weight involved, and the* expense. But those things arc factors which time and experience may be depended on to simplify if the principle bn sound and the device prove acceptable.