AHEAVYWEIGHT BUT SOFT ON THE SOILS

17 October 1997

AHEAVYWEIGHT BUT SOFT ON THE SOILS

BIG, bold and, well, almost beautiful – the Case Quadtrac, a tracked version of the articulated 360hp 9370 Steiger, features four rubber track drive units at each corner.

It is a design pioneered by Case and claimed to provide the 19.8t tractor with a ground pressure loading of just over 5psi, rather than the 14psi when shod on conventional tyres.

The track units themselves comprise a positive drive from a toothed wheel down to two large tensioning pulleys and three idler pulleys. Not only are the units designed to pivot longitudinally they can also have a degree of lateral movement to help the tracks maintain maximum contact with the ground. Ground contact is also enhanced by the ability of the whole tractor to oscillate at its pivot point.

Track tensioning is hydraulic and automatically monitored and adjusted though the tractors hydraulic system.

Power is provided by a six-cylinder Cummins engine driving through a 12-speed powershift box and lastly to axles specifically designed to cope with the demands of the track units.

The UKs first Quadtrac found its way to CWS Agricultures Essex Farms near Ongar early last month, a 1940ha (4800-acre) arable unit run by manager David Watson. On his own admission, Mr Watson is a big-tractor enthusiast.

"Large acreages need big pieces of machinery to make sure crops are planted and harvested on time, and costs are kept to a minimum," he maintains. "We employ just five full-time staff."

But Mr Watson is also aware that heavy machinery causes compaction, meaning he then has to spend money on subsoiling operations, a vicious circle which could now be broken after the arrival of the Quadtrac.

"It is a mean machine," he enthuses. "Not only is it capable of high work rates with low compaction levels, it is narrow enough to travel safely down roads. With our land split into units several miles away from each other this, is an important feature."

So, what is the Quadtrac like to drive? Arriving at the cab after several feet of vertical ladder is to find a spacious living area complete with well laid out controls and dashboard. It is, in effect, the same as found on the Steiger.

With the engine started, forward direction engaged after depressing the clutch, the tractor moves off. Changing gear is performed merely by pushing the selector lever forwards or backwards as required.

The ride is smooth, even over rough ground, although, as with most tracked machines, excessive speed on tarmac can be a juddering experience.

With the steering a bit on the twitchy side, there is a tendency to over-steer, but this would clearly be eliminated with practice. And the use of tracks does not appear to impose on a respectable turning radius.

"The idea is to use the tractor for the vast majority of our cultivation work," explains Mr Watson. "We have tried it with a 10-furrow plough and even on some of our testing soils it runs away with it. And the same goes for a 7.5m stubble cultivator." &#42

CASE QUADTRAC

&#8226 Engine 14-litre, 360hp 6-cylinder Cummins.

&#8226 Transmission 12-speed powershift.

&#8226 Track width 75cm.

&#8226 Turning radius 6m.

&#8226 PTO 1000rpm.

&#8226 Ground pressure with hydraulic hitch 5.3psi.

&#8226 Fuel capacity 946 litres.

David Watson, farm manager of CWS Agricultures Essex farms, near Ongar, took delivery of the 360hp articulated Quadtrac last month.