Knight Farm Machinery has extended its self-propelled sprayer range with a return to forward-control conversions - this time based on JCB’s latest 4000-series Fastrac. Geoff Ashcroft takes a closer look.
Knight has form when it comes to building forward control sprayers, and this latest version paves the way for more Knight self-propelled models.
The wraps came off Knight Farm Machinery’s forward-control Fastrac conversion at last month’s Lamma Show.
Developed initially to meet the needs of spray contractor Agrii, the conversion is an extension to the Knight portfolio, and creates a power unit with a large platform that can see the spray pack substituted for a high-capacity spreading body.
“We can see great potential for this forward control conversion, particularly for contractors,” says Knight Farm Machinery’s technical manager David Main.
“And with the Fastrac 4000 using a hydro-mechanical continuously variable transmission (CVT) and perhaps the best tractor cab on the market, it provides a generous load platform from which a specialist application machine can be developed.”
“The Fastrac 4220 also benefits from self-levelling suspension and twin caliper brakes.”
Mr Main says the conversion process has been far from simple. Doing so has required a return to the drawing board, with guidance from JCB, to re-engineer and repackage the tractor to meet the specific needs of its customer, Agrii (see panel).
The project was conceived at the end of 2014, when Agrii approached Knight to build a bespoke self-propelled sprayer. It was given the green light following consultation with JCB in spring 2015.
“All we had was a cut and paste drawing taken from a JCB brochure, that allowed us to visualise how the new Fastrac could look as a forward control sprayer,” he says.
“JCB was happy to approve what we wanted to do, and it maintains its ethos of working with OEMs,” he says. “Right from the outset, we wanted to maintain as much of JCB’s DNA in the conversion work - right down to the branding.”
With a 4220 delivered to Knight’s premises at Wireless Hill, Stamford, the firm carefully dismantled the tractor.
With the front utility block removed, a steel frame was manufactured onto which the cab could be mounted. This picked up on the bolt pattern used to locate the four-tonne capacity front linkage and enabled the cab to be secured in the forward position.
It also affords mountings for a hydraulically raised and lowered frame for granular applicators.
With CanBus wiring, loom extensions were made to allow the original control system to operate, with trunking providing a means to protect wiring as it extends forward from the middle of the tractor to the back of the cab.
The tractor’s nose cone was removed from the bonnet and then carefully trimmed to create a pattern for a new narrow cowling that could be used to conceal the steering and braking connections at the front of the cab.
Lighting configuration was also changed, as the slim cowling carries fewer lights than the tractor. To overcome this, Knight created a moulded front panel to tidy the bottom edge of the cab, into which headlights could be mounted.
“Unlike the Claas-derived Vista cab, the Fastrac’s front screen is not all floor to ceiling glass - there’s a cut-out for the front bulkhead that carries the steering column,” he says.
Inside the cab, the interior remains unchanged, save for a push button on the left-hand B-post to lower the steps. Knight has also piggy-backed its sprayer joystick onto the tractor’s joystick, maintaining operational simplicity.
The middle of the tractor posed the greatest challenges, as the firm sought space to fit large diameter R46 rowcrop wheel and tyre equipment without compromising on manoeuvrability. The Fastrac’s fuel, diesel exhaust fluid (DEF) and hydraulic tanks are nestled between the left-hand wheels, while the exhaust after-treatment module, batteries and other ancillaries are carried between the right-hand wheels.
“We had to engineer more space between the wheels, which meant repackaging components,” he says.
Knight manufactured replacement fuel and hydraulic tanks to replace the original extruded tanks, though it was able to re-use the DEF tank. At the same time, it created space to mount the induction hopper on a parallelogram linkage.
On the right-hand side, the exhaust after-treatment kit was relocated and a new exhaust stack formed. “We took advantage of available height and used space beneath the boom, when in the transport position,” he says. “The taller fuel tank gets a sight gauge, so operators can see when the tank is almost full.”
It would have been easy for Knight to take an existing 4,000 litre spray pack from its 2040 self-propelled and graft it onto the back of the Fastrac, but this was quickly ruled out.
“With the tractor stripped back to a bare bones, and tank chassis installed, we could see that we had to make a spray pack specifically to suit the Fastrac’s chassis,” he says. “Though it does use some of the 2050 demount components.”
At the rear of the tractor, the three-point linkage, pickup hitch, cross shaft and associated components were stripped away to save weight. This enabled a Rockinger hitch to be installed, to suit Agrii’s bowser towing requirements.
Hydraulic spools have not been wasted - the spray pump, boom fold, slug pelleter frame and pressure washer all use the tractor’s spools, and are controlled form the armrest.
To maintain engine access, Knight created a walkway alongside the cab - reusing JCB’s original step plates - to allow the operator access via a hinged platform behind the cab. This allows the bonnet to be lifted and its installation remains unchanged.
“We’ve fitted a larger mesh over the cooling pack, which can be unclipped and removed for cleaning,” he says.
Far from being a blacksmith’s creation, Knight has sympathetically re-engineered the Fastrac 4220 to create a specialist forward control power unit. And with JCB’s approval, the Stamford-based manufacturer suggests that it could become the worldwide ‘go to’ OEM supplier of all future Fastrac forward control conversions.
When it comes to contract spraying, Agrii lays claim to the UK’s largest fleet of sprayers covering the most hectares - its 37 self-propelled sprayers dispatch 200,000 hectares/year.
Its an eclectic fleet, and comprises a mix of most types of self-propelled rig, which gives the firm vast experience in selecting sprayers for specific tasks.
“We wanted a couple of high capacity machines with great manoeuvrability that could run large diameter R46 tyres to boost ground clearance,” explains Agrii contracts support manager Neil Millar. “But we also wanted mechanical transmissions and the ability to tow 12,000 litre bowsers.”
“The new Fastrac 4220 with a CVT seemed the ideal power unit, but we didn’t want a stretched chassis and longer wheelbase - it had to be forward control to provide a generous load platform and good visibility.”
“We felt we could work with Knight to deliver a professional conversion that would suit our businesses needs,” he says.
Knight’s Fastrac forward control conversion includes a 4,000-litre tank with a 30m boom, which has the ability to also operate at 28, 24 and 21m.