27 March 1998

MOWER MAKERS THINK BIG

TO KEEP UP

As self-propelled foragers

gain heftier appetites for

grass, so mowers capable of

increasingly greater outputs

are being sought by a

growing number of

contractors. Peter Hill

reports on the coming of

the self-propelled mower

FIRST, it was self-propelled forage harvesters. Now, grass mowers are taking the "self-propelled" route to bigger capacity in an attempt to keep up.

For contractors, the big capacity forager is an essential means of packing more work into a busy season. Volume is everything in this cut-throat sector of contracting service and, to compete successfully, operators are having to invest in ever more expensive kit to maintain timeliness and get as much work as possible under their belts.

Until now, wider working trailed mowers and mower-conditioners, then front-mounted/rear-trailed combinations, have been the only route to increased mowing capacity. But the purpose-made self-propelled machine is on its way.

Going wide is all about cost-effective productivity, especially if that means cutting a tractor and smaller mower out of the silage team. There are risks in putting all eggs in one basket but also operational advantages in managing logistics with fewer men and machines.

Several contractors have already dipped their toes in the self-propelled mower waters, using either reverse-drive tractors with home-made or purpose-built triple mower assemblies, or self-propelled forage harvesters that have been superseded by newer machines but still have capable power units.

According to Robert Targett, output and manoeuvrability are the main attractions of the reverse-drive tractor/triple mower combination run by the R &#42 & E N Targett & Sons silage contracting operation.

"It works well and has got over our problem of keeping in front of the forage harvester," he says. "Typically, it will cut around 40ha (100 acres) a day but we have had it up to near 50ha (124 acres)."

The Targetts experimented with self-propelled mowing when they built their own using an MF combine chassis with all the harvesting elements stripped off. That left the engine, hydrostatic transmission and cab, to which three mowers, cutting 6.7m (22ft) of grass in one go, were added.

"It had very good visibility and the hydrostatic transmission was ideal," Robert recalls. "But the mowers were not really up to the job."

Next, it was back to a front- and rear-mounted mower combination. But capacity was still marginal as the mowing outfit could keep ahead only if everything went smoothly, so options had to be re-considered.

A solution appeared in the guise of the Claas Corto 8100F – three drum mowers arranged on a frame for mounting on the back of a reverse-drive tractor. The Targetts opted for a 180hp Massey Ferguson MF8150 with reverse-drive conversion carried out by a French engineering firm.

Main attractions of this layout, says Robert Targett, are visibility and manoeuvrability.

"With a front-mounted mower, you cant see anything thats hidden in the grass – we once hit a tree stump which didnt do the mower a lot of good," he points out. "But with reverse drive, you are closer to the mowers and have a clear view.

Good visibility also helps when working in small fields which, because the mowers are fully mounted, can be tackled more efficiently than with a trailed or front/rear combination, especially when having to get into awkward corners.

"Awkward-shaped fields are also less of a problem, thanks to the wide cutting width," Mr Targett adds. "With this mower we go round only three times before cutting up and down rather than perhaps eight or nine with a conventional machine."

The Claas triple-mower comes in one working width – 7.7m (25ft 4in), folding to 2.98m (9ft 9in) – but two versions; one for use on reverse-drive tractors, the other for 600-series Jaguar self-propelled foragers. As contractors progressively switch to the more powerful 800-series, Claas expects a growing number of 600s to be stripped of their chopping gear and turned into self-propelled mowers.

Fellow German mower manufacturer Niemeyer also makes a triple-mower for tractors and forager power units, UK importer Opico offering two working widths – 7.5m and 8.3m (24ft 8in and 27ft 3in) – using disc cutting beds, with or without flail conditioners.

There is also a choice of configurations. Front-mounted mower plus two rear-mounted machines on outriggers for conventional tractors; three mowers in front-mounted triple formation for conventional or reverse drive tractors; and the same configuration for a self-propelled forager power unit.

As with the Corto, all these configurations leave three individual swaths, as does the Krone Big M, the first of a likely new breed of purpose-engineered self-propelled silage mowers.

This hydrostatic-drive machine carries three Krone disc mower-conditioners to cut 9.1m (30ft) of grass in one go. One is mounted up-front with two more positioned either side amidships. The folding wing units reduce transport width to just 3m (9ft 10in) while a tight-turning rear axle helps manoeuvrability in the field and on the road.

Power comes in the shape of a 300hp John Deere diesel engine powering a hydrostatic drive system with radial piston motors on each of the equal size wheels giving three speed ranges in all. The John Deere forage harvester cab houses the driver.

Several contractors had the chance to sample this power mower during last years silage season and the company is hopeful that one or two will opt to add the machine to their foraging teams for this years campaign.

Deutz-Fahrs Grasant is a more radical design that was put through preliminary trials with a commercial operator under UK conditions last year. Powered by a 260hp Deutz air-cooled engine and two-speed hydrostatic drive, the Grasant uses a 6.4m (21ft) plain disc cutterbar mounted across the front of the machine and folding to 3m (9ft 10in) for transport.

Main difference from other mowers of this capacity – Deutz-Fahr reckons on spot work rates up to 4.5ha (11 acres) an hour – is that grass is then channelled into the body of the machine to be processed by a high-speed conditioning system. First, a gathering auger on the cutterbar brings material to the centre, where a combine harvester-like crop elevator delivers it to a pair of compression rollers, then three ribbed rollers.

A larger of these, running at up to 3000rpm, works in conjunction with the two smaller ribbed rollers to provide an intensive – and adjustable – rubbing action designed to break through the moisture-retaining wax coating on stems while causing minimal leaf damage.

A conveyor belt delivers the processed forage to rotors at the back of the machine where grass can be dropped in a weather-proof swath or spread across the mown area using adjustable vanes.

The combination of intensive processing and spreading means grass can be wilted, in favourable conditions, to high dry matter levels in four to seven hours, reducing the time crop is exposed to catchy weather. In-cab control regulates processing intensity and spreading width.

Conventional tractors fitted with reverse-drive controls and a big mounted mower make effective self-propelled cutting machines. This 180hp MF8150/Claas Corto 8100F combination is operated by Somerset contractors Robert and Colin Targett.

Deutz-Fahr Grasant is the more radical of two purpose made self-propelled mowers. The disc mower cuts 6.4m (21ft) in one go.

Krones Big M packs a 300hp engine and three-speed hydrostatic drive to cope with the triple-deck 9.1m (30ft) mower-conditioner.

Self-propelled and reverse-drive tractor-mounted mowers


Make/model Format Power Cut width List price

Agrimech Four-drum mower for 200hp 6.1m poa

self-propelled power unit (20ft)

leaving two separate swaths

Claas Corto 8100FT Triple drum 200hp 7.7m 27,900

mower for reverse drive (25ft 4in)

tractor leaving separate swaths.

Claas Corto 8100F Triple drum 200hp 7.7m 29,600

mower for 600-series Jaguar (25ft 4in)

self-propelled forager leaving separate swaths.

Deutz-Fahr Self-propelled with 260hp 6.4m poa

front-mounted mower (21ft)

Grasant 260hp and internal conditioning system, leaving 290hp

single or spread swath.

Krone Big M Self-propelled with 300hp 9.1m 125,000

front-mounted and two (30ft)

side-mounted disc mower-conditioners

leaving separate swaths.

Niemeyer SM750 Disc mowers or- 110hp 7.5m 19,874

mower-conditioners in front (24ft 8in)

Niemeyer SM750 Cmounted/two rear- 130hp 27,652

mounted or triple front, reverse drive or self-propelled configurations.

Niemeyer SM850 Disc mowers or mower– 130hp 8.3m 22,356

conditioners in front (27ft 3in)

Niemeyer SM850 Cmounted/two rear- 150hp 29,608

mounted or triple front,

reverse drive or self-propelled configurations.