6 November 1998

Shifting more beet, faster

Conventional trailers used

for hauling beet from field to

clamp have their limitations

when the going gets tough.

Ian Marshall visited one

Cambridge contractor who

has found solace in a Big A

conversion

PROBABLY the only unaltered component on Nigel Harrisons Big A is the front wheel.

The origins of the machine are still recognisable, but it is now longer and the engine is under the cab.

These changes are only some of those made when Mr Harrison set about converting a secondhand Big A into a specialist, 14.5t capacity low ground pressure, sugar beet transporter.

"With over 3500 acres of beet to lift each season I needed a high capacity vehicle to take the beet from the harvester to the clamp, which did not leave the driver completely exhausted at the end of the day," says Mr Harrison, who runs his contracting business from Speedwell Farm, South Brink, Wisbech, Cambs.

A look around the market revealed there was little to offer in terms of a transporter capable of combining high capacity with low ground pressure – the latter an important requirement if soil damage is to be minimised. "There are low ground pressure transporters on the market, but they are not specifically designed for sugar beet and with a price tag up around the £100,000 mark, they are expensive," says Mr Harrison.

So, a used Big A went into the farm workshop in May and emerged in its current form after 1400 man hours of work to haul its first load of beet in mid-September.

"To keep the cost down, we cannibalised a lot of components, but all were reconditioned before refitting," says Mr Harrison.

The single front wheel concept has been kept for its low ground pressure characteristics and its turning circle reduced by fitting longer stroke steering rams.

But the chassis has been both strengthened and lengthened by 2.5m (8ft) to give a large overhang to enable it to be backed well into the heap without having to run over beet already in store.

Above the chassis sits the body, taken from an old six-wheel-transporter complete with a hydraulically-operated self-levelling tailboard and, below it, a tandem axle unit, taken from a dumper truck whose previous life was in quarry work.

At the front end, the cab was moved forward above the engine.

The Big As 220hp V-6 2-stroke Detroit diesel is coupled to its the original Allison four-speed automatic transmission which has been converted to a five speed by the inclusion of a creeper gear, with the drive taken to modified lockable differentials in the rear axle unit.

"We needed to be able to travel at a speed to match that of the harvester in all conditions," says Mr Harrison.

These modifications were relatively simple. The biggest headache was getting the right load height, which was achieved by sinking a sub chassis inside the main chassis. There was also the problem of getting the correct angle for the prop shaft so that the universal joints were not being over worked.

"With the engines original position there was a 17í angle from the gear box to the rear axle. We had to drop the engine 25cm (10in) to get the 8í we needed," he says.

To date, the transporter has carted about 10,000t of beet servicing a six-row self-propelled Agrifac ZA 215 EH harvester. By the end of the season it will have been involved in lifting about 708ha (1750 acres).

"Mechanically the machine is sound and we have had no major problems," says Mr Harrison. "We have about 75% of the machines weight on the rear which, combined with the running pressures of 14 and 20psi, gives minimal ground compaction. Unless conditions are extremely bad, we can keep harvesting without making a mess.

"We are now looking to build the unit commercially, when the only changes would be cosmetic and upping power to about 300hp." &#42

"We needed a fast, large capacity specialist transporter, which would not leave the operator tired out at the end of a 12-hour day," says Nigel Harrison.

Bespoke tailored to minimise soil compaction when hauling sugar beet from harvester to clamp, M W Harrison & Sons 14.5t Big A based transporter cost about £70,000 to produce.