With the need to tread as lightly as possible when harvesting grain maize, one Warwickshire grower commissioned his own design of chaser bin to run with the combine. Geoff Ashcroft reports.
Rob Hadley is no stranger to growing grain maize. Having produced the crop for two seasons now for local customers, he has continually fine-tuned his harvesting approach to limit the impact on soil structure.
With dual wheels on the farm’s Claas Lexion 420 combine accompanied by flotation tyres on the rear axle, the last piece of the low ground pressure puzzle was finally put in place in time for the 2020 harvest – a specially-built chaser bin.
“I wanted to keep trailers out of the fields,” says Mr Hadley, who farms 607 hectares from Chesterton Fields Farm near Leamington Spa. “This was a two-fold solution – looking after the soil structure by managing compaction, and also keeping mud off the roads.”
Having repeatedly searched to buy a chaser bin suited to his needs, he eventually turned to Ivan Kendle of engineering company North Norfolk Vehicle Solutions, to explore having a chaser bin purpose-built for his harvesting requirements.
“I had my eye on a Richard Western drill filler, but the auger was just too small,” he says. “It was nigh-on impossible to find anything suitable, and so the only option left was to look into having something built.”
“Knowing Ivan from shared interests with pedigree South Devon cattle, I scratched out my idea on the back of a fag-packet and put it on his desk,” says Mr Hadley.
Key requirements were a modest capacity bin, built around a small, lightweight unit that was also well-balanced and easy to handle.
“It needed to follow the principles of a gravel cart,” he says. “Manoeuvrable, sensible capacity, big tyres and easy to pull. It is only intended as a buffer for the combine, so it does not need to hold 20 tonnes, or need 300hp up front.”
Two years in the making, the finished version of Mr Hadley’s chaser bin idea arrived at Chesterton Fields Farm ready to handle 2020’s 142ha grain maize harvest. The single-axle bin offers an eight-tonne capacity, and sits on 800/65 R32 flotation tyres creating generous ground clearance and a long, wide footprint.
When it comes to tractor requirements, the bin needs only a pto input to drive the 300mm diameter unloading auger, and two spools – one to vary the intake slide for crop flow onto the auger; the other to fold the top section of the auger for transport.
Though this model is not a one-off. Looking into the economies of scale, NNVS built four identical models, working out at a cost of less than £10,000 each, when supplied with 17.5 R25 industrial tyres.
“It is an extremely simple design, and one that works very well,” he says. “Though we are still learning when it comes to auger and flow control, to suit the varying moisture content of grain maize.”
He says that the 2020 maize harvest season was a particularly challenging one, with prolonged wet conditions that thoroughly tested man and machine.
Fortunately, the steep-sided bin prevents crop from bridging, though the similarly steep auger has sometimes proved reluctant to convey wetter material.
“It was a much longer harvest than usual, and over the seven months we were cutting, we saw crop from 16 to 40 per cent moisture content,” he says. “It has been a thorough test for the bin.”
“The drier grain came earlier this year, and proved the easiest to handle,” he says. “I think the steep angle of the auger means we will need to look into re-designing the intake throat for handling those wetter crops.”
“But it does what I wanted and it is so much kinder than bringing a trailer into the field during the late autumn and early winter,” he says. “And you do not need a big tractor for the chaser, this is easily handled with just 170hp.”
An early modification was the installation of a chute extension, shortly after the first few field runs saw wet grain maize piling up on one side of the trailer when unloading.
“High moisture content stops the grain from flowing, so we had to fit a chute extension to be able to drop the grain into the middle of the trailer,” he says. “I cut up an old steel fuel tank, welded the plates to suit the auger outlet profile, then added a hinge so it could be folded for road transport. Job done.”
Mr Hadley says the chaser bin has proved to be the easiest and most cost-effective way of boosting combine performance.
“The combine is no longer running to a headland to unload maize, it can just keep going,” he adds. “We can keep cutting, and unload on the move into the chaser, then shuttle grain to the headland or gateway where an empty trailer will be waiting.”
In-field performance is said to be impressive when shod on the flotation tyres, and Mr Hadley has recently found more uses for the bin away from grain maize.
“We have a set of narrow industrial tyres for the chaser bin, which lets us use it as a drill-filler too,” he says. “It lets us get under the auger with the four metre combi.”
“We will probably add a couple of extra viewing panels at the front of the bin, as you rely on the combine driver to know when you have got enough on board. And the first window is not low enough to see when the bin is empty, or when wet grain will not flow.”
That said, first season performances have left a positive impression on the Hadley team.
“I would probably have a slightly bigger auger if I was building another – a larger diameter would be better on wet material,” he adds. “And a longer auger would mean I could load into lorries, although that was never on my radar, and is something that we do not really need. It has been built to suit our trailers, and that was the primary unloading requirement.”
There are few finishing touches to be applied, one of which is to add a wiring loom and road lights.
“We have used a Connix wireless system as a temporary solution, but the plan is to fit a hard-wired lighting system so we can add a flashing LED strobe, and install a series of worklights on the corners of the bin. This will also help with loading and unloading, at night.”
Mr Hadley also intends to make the most of this new development on a wider range of tasks.
“We will use the chaser bin for our cereal harvest too,” he adds. “We can use it to improve in-field traffic management to help further look after our soils, by keeping trailers off fields and limiting compaction.”
“I have even used it to mix a bit of feed for our South Devon cattle,” he says. “It is brilliant, for much less than the cost of other chaser bins out there.”