Kuhn is to replace its best-selling twin-disc fertiliser spreaders for 2006.

Built by German manufacturer Rauch, the medium capacity, mid-specification Axera 30.1 and 40.1 will cover 24m and 36m bouts respectively and as such supersede the highly popular MDS 1132 and 1142.

The firm says that the main brief given to its design engineers was to simplify the set-up procedure to ensure easy adjustment of application rate and spread width.

And this is where the most significant developments are made.

Application rate

To alter application rate the operator moves a handle – situated on the side of the unit – along a sliding scale.

This changes the hopper aperture, varying material flow onto the spreader discs.

And it is this hopper aperture that Rauch says is key to the new spreaders’ accuracy.

The hopper outlet – which controls material flow onto the discs – affects the evenness of spread.

Increasing the application rate means the hopper outlet has to be wider, in turn meaning the width of the band of material dropping onto the discs is wider.

According to Rauch, this has an adverse effect on spread pattern.

To overcome this, the company has developed an unusual foetus-shaped aperture that drops material in three different places along the vane.

This is said to minimise the effect of varying application rates on the spread pattern.

Spread width

The only major difference between the two models is the discs.

Those on the Axis 30.1 are for spreading from 12-28m and from 24-36m on the 40.1.

Another sliding scale alongside the rate settings lever adjusts the spread width by altering the point at which fertiliser drops onto the vane.

The speed at which the discs spin also has an effect on the evenness of spread along – rather than across – the bout.

According to Rauch, by running the discs at a faster speed than before, the frequency at which bands of fertiliser are thrown out by the vanes is increased, thus evening out the spread pattern.

But running at such high speeds, the discs have a tendency to create a suction effect which affects application rates.

Material is drawn from the hopper more rapidly than it would be at calibration.

This is because most spreaders are set up with the discs removed.

To overcome this, a brush cowling is fitting around the hopper outlet which – as well as reducing the suction effect – limits prill bounce on the discs.

The spreaders will be available in basic format with hydraulic controls or with a more sophisticated electronic system that maintains a set application rate regardless of forward speed.

Costing an additional 1770, this setup is GPS compatible and can be used to vary application rates to match crop requirements across the field.

With hopper capacities ranging from 1200-litres to 3000-litres, prices for the Kuhn Axis start from 3962.

fwmachinery@rbi.co.uk