Alpha better? Answer, yes

4 April 1997

Alpha better? Answer, yes

It looks a little quirky, but Hardis Alpha self-propelled sprayer has some novel design features. Peter Hill gave it the once-over for this First Drive report

ATTEMPTS by Danish sprayer giant Hardi to offer a sound self-propelled sprayer have previously not met with a lot of success.

Early machines lacked the four-wheel drive and four-wheel steering that are now commonplace, they were under-powered to some extent, and had mechanical rather than hydrostatic drive which meant losing out in the crop clearance stakes.

The Alpha, in contrast, is a more attractive contender in the sense that it fits current spec requirements. Built in France by Hardi group company, Evrard, it has selectable four-wheel steering, wheel motor hydrostatic drive, plenty of power – up to 167hp – suspension front and rear, and a good sized cab.

It would not win a beauty contest, but the front engine/mid-cab design is reckoned to give more even weight distribution – particularly when the big six-cylinder engines are fitted – than if these two assemblies were positioned vice versa. With the four-cylinder turbo and 24m (80ft) boom installed, weight distribution is pretty much unaffected by spray tank contents.

The layout also means there is easy service access to the power unit which, on other machines, is often tucked well out of sight; the transmission pump is a little less easy to get at, but the cabin can be tilted sideways if serious work is needed.

The cab location certainly gives the machines driver more natural steering feedback than when he is slung ahead of the front axle, not to mention a commanding view ahead, to the side and over the low-slung tank to the rear.

This much was evident during a brief spell behind the wheel near Hardis UK base at Hinckley, Leics, when the effect of the machines suspension could also be judged to some extent. This is conventional, in as much as it uses coil springs and telescopic dampers, but unconventional in layout – just one large diameter spring at the centre of each axle, flanked by vertical dampers.

Rubber bump stops within the springs limit compression while two short cables between chassis and axle prevent excessive spring extension. Track widths are fixed at present but adjustable axles are likely before long.

Jolt-free ride

Principally, the suspension is there to give machine and driver a relatively jolt-free ride when spraying at 8-13kph (5-8mph). This it does satisfactorily, particularly in combination with soft low-ground pressure tyres which add to the cushioning effect. The system is not quite so adept at ironing out more severe knocks, however, such as when traversing tramlines.

Like most self-propelled sprayers, the suspension is not independent. The rear axle is attached rigidly with only up and down movement permitted, while the front axle is mounted on a pivoting subframe so that the vehicle can follow natural contours.

Unlike most machines of this type, though, the axles are attached to the chassis mountings by very short arms – lugs more like – instead of the more common long "A" frames. This reduces the amount of metal involved but results in rather more frantic axle movement and a strong torque reaction that sees the back-end squatting and the nose lifting whenever the vehicle moves off.

Its not necessarily detrimental to performance, just something that takes a bit of getting used to.

The chassis is a relatively lightweight affair but strong with it, being designed as a fairly flexible assembly formed from "U" section steel and bolted cross-members. This, reckons Hardi, should stand up to the rigours and stresses of high-speed field operation better than a more substantial but also more rigid construction.

As far as spray gear is concerned, things are rather more Hardi-familiar. A sizeable sump to the rear of the 2000- and 2500-litre (440 and 550gal) moulded plastic tanks helps evacuate the contents while lowering the centre of gravity, and the same goes for the partitioned steel tank slung inside the chassis; this holds diesel in one side, water for cleaning through the spray system in the other.

A 15-litre (3gal) hand-wash reservoir is built into the spray tank, discharging via a small flexible pipe at the point where the Hardi Manifold system of valves is located – alongside the drop-down chemical filler.

Fitting a pump on/off and engine speed controller nearby enables sufficient revs to be called on to get the six-cylinder diaphragm piston pump up to full filling capacity, without the operator having to jump in and out of the cab.

The spray boom is Hardis OLH parallel linkage design, also fitted to demount units and the new Commander trailed sprayer. Its available in six sizes from 18m to 28m (59ft to 92ft).

Aluminium boom

Alternatively, buyers can opt for a 24m or 28m (80ft or 92ft) aluminium boom, to save weight and/or to use the Stabilor ultrasonic boom height/levelling control.

At the opposite end of the Alpha, manual pull-up steps alongside the vehicles prominent nose lead to a small tank access platform and roomy cab. Entry is through a sliding door and, once in the seat, the driver gets a good view across the one-piece bonnet as well as in all other directions.

A large blank moulding makes it obvious where Evrard sites the instruments on its version of the Alpha; on the Hardi, this space is for decals explaining how to use the arm-mounted Pilot controller. This provides easy access to all machine functions, with a large screen providing the detail.

Sprayer operation switches are carried on the hydrostatic control stick, but other switches and buttons – for boom folding, wheel motors and so on – are rather more scattered. A large foot pad to the right of the adjustable steering column engages four-wheel steer to make tight headland turns, in preference to the auto systems fitted to several UK-built self-propelled sprayers.

At least there is no risk of charging off down the road in four-wheel steer – provided the right foot is kept well clear of that pad.

Far left: Hardi Alpha sits on relatively small diameter tyres, whether low ground pressure or row-crop; the chassis design provides lots of ground clearance and four-wheel steer is engaged by a foot pad. Note colour-coded spray system valves alongside chemical filler. Alpha prices are from £52,745.

Left: Room and a view – heaps of glass means good all-round visibility. Hardi Pilot controller neat but other controls and instruments are somewhat scattered.


&#8226 Engine choice 111hp, 133hp and 167hp Deutz liquid-cooled diesels.

&#8226 Transmission Sauer hydraulic pump and two- speed Poclain wheel motors, giving three speeds and variable torque split.

&#8226 Steering Two-wheel steer with four-wheel steering engaged by foot pedal.

&#8226 Suspension Single coil spring, twin telescopic dampers per axle; rubber stops, cable extension restraint.

&#8226 Spray tank 2000- or 2500-litre (440gal/550gal) with built-in 15-litre (3gal) clean water, hand-wash reservoir.

&#8226 Boom Hardi OLH 18m-28m (59ft-92ft) steel or ALU 24m-28m (80ft-92ft) aluminium.

&#8226 Spray gear 240-litre/min (53gal/min) Hardi piston diaphragm pump; self- cleaning filter; Manifold valves; Pilot control and monitoring system.

&#8226 Price from £52,745 for 111hp/2500-litre/24m spec.

See more