MOWERS WITH MUSCLEWILLCOSTMORE…
The latest high output
mowers offer massive cutting
capacity, but they also
demand plenty of horsepower
and a big budget, says
WORK rates now available from the top mowers and mower-conditioners would have been unthinkable just a few years ago, but so would the idea of using a 250hp to 300hp engine to cut grass.
Krone set the pace when it announced the pre-production version of its Big M self-propelled mower in 1997. It has three 3.2m cutting units, each with a V-tine conditioning rotor with adjustment for either a 700 or 1000rpm working speed, and the cutting width is 9.1m.
Power for the Big M is provided by a 300hp John Deere engine, and the three-range hydrostatic transmission provides four-wheel drive through piston type wheel motors. Maximum travel speeds in each range are 10, 20 and 40 km/hr, but the top range is for road use and drives through the front wheels only. The cutting units fold hydraulically to give a 3m transport width.
Design improvements since the first prototype version was announced in 1995 include increased manoeuvrability, with the turning circle reduced to 9.0m, and the fuel tank capacity was increased to 460 litres to extend the working hours between refills. The production model was shown at Grassland 99, with the availability for UK customers scheduled for this season, but no machines have been sold here so far.
Deutz-Fahr took a different approach when it developed its Grasant self-propelled mower-conditioner, which was also shown in its final production form at last years Kemira Grassland event. Instead of using a triple mower approach the Grasant has one front mounted rotary mower with a 6.40m working width.
The speed of the conditioning rotor is adjustable up to the 3000 rpm maximum, and the swath can be adjusted from 1.6m to a 6.00m width spread.
The Grasant is available with 260 and 290hp Deutz engine options, and the work rate is up to about 4.5ha (12 acres) per hour, the makers claim. Although the Grasant has appeared at public demonstrations and has also been used for evaluation work under UK conditions, no machines have been sold here so far.
While self-propelled mowers have made a slow start in the UK, triple mower sets for use on big tractors are already well established. Benefits claimed for the tractor powered approach include lower initial costs – assuming a suitable tractor is already available, and there is no costly engine and transmission to stand idle while the mowers are not being used.
Claas announced its Disco 8500 triple disc mower-conditioner set in the UK for the 1999 season. They sold six of them in the first year, and this years sales are expected to equal or even exceed the 1999 total, according to Claas UKs green harvest specialist, Jeremy Wiggins. All the customers are contractors who must have high output mowing capacity to keep ahead of big forage harvesters, he says.
Each of the three units of the Disco 8500 has a 3.0m cutting width. With a 25cm overlap to avoid striping on corners, this gives an 8.5m working width. A central pivot point on each mowing unit allows lateral movement for contour following, and the middle unit also has a spring suspension to allow two dimensional movement.
Claas developed the 8500 mainly for high horsepower tractors, including its own 250hp Xerion model, but there is also an 8500C version for mounting on a forage harvester. The forage harvester version is more expensive because it has special drive lines and a different folding mechanism, but the idea is popular on the continent because the high horsepower and hydrostatic drive used on most foragers are ideal for mowing, explains Mr Wiggins.
"Most UK customers want the tractor version, using either the rear linkage of a reverse-drive tractor or a conventional tractor with a front linkage. We also have one customer who is using a Disco 8500 on his Xerion tractor," he says. "The horsepower requirement depends on the crop, the ground conditions and the adjustment on the conditioner. You can get away with just under 200hp, but we recommend 200hp plus, and 250hp is ideal."
Plenty of power
Work rates with plenty of power available can be high, and 10 ha or 25 acres per hour was recorded by one UK contractor who took part in the Disco 8500 evaluation programme in 1998. Prices start at £28,700 for the tractor version, and the 8500C for forage harvester mounting is priced at £38,000.
The advantage of using a forage harvester for mowing is that it can utilise an elderly machine which is no longer used for its original purpose. Conversion kits to adapt most of the leading makes of self-propelled forager are available from Lynx Engineering, of Long Buckby, Northampton. They consist of a front linkage, a gearbox and pto drive for the front of the forager, and this allows mower or mower-conditioner units up to about 8.0m wide to be handled.
New lease of life
Using the adaption kit gives a new lease of life to a machine with a big engine, says Nick Ewbank, Lynx Engineerings owner, and it also avoids tying up a high horsepower tractor at a busy time.
"There are plenty of old forage harvesters about with a clapped out chopping mechanism, but the engine and transmission are usually still in good condition," he says. "A lot of contractors have a suitable forager in their yard, and there are plenty of them available from dealers for about £15,000. They usually have an engine producing well over 300hp, and this means there is plenty of power available for an 8m wide mower-conditioner."
The conversion kit costs about £6075 and the fitting charge adds about £380 to the final bill. *
Above: The Grasant self-propelled mower-conditioner from Same Deutz-Fahr
is not yet available
in the UK.
Left: Krones Big M self-propelled mower conditioner has
three cutiing units.