Hardware, sofTware and servicePonsse ergo 8waT hOmE ON ThEfrENch SlOPESOur French customers have expressed their need for better performing <strong>PONSSE</strong> machinesfor sloping sites. We responded to the challenge by developing an eight-wheel version of theErgo harvester.The first much-awaited machines were delivered to the Limousin region of France. The newmodel is much more than just the conventional Ergo with eight wheels.EfficiENT harVESTiNG PErfOrmaNcEHarvester operator Frédéric Foucaultworks for Mécafor, a company located inthe region of Corrèze in France. He hasbeen working with the new Ergo 8w fortwo months. Frédéric is more than pleased.The harvester's eight-wheel feature and thepositive feedback on the design from theoperators encouraged the company to investin two Ergo 8w harvesters. It is a signof trust in the properties and performanceof the machine, as well as in the servicesprovided by the Ponsse Limousin team,who work in the city of Peyrat-le-Châteauin the region of Haute-Vienne.The harvester moves around the steeplot in a nimble manner. The soil on thebanks of the River Vézère is extremelywet, but it manages well," Frédéric says.After he started using the eight-wheeler,Frédéric has not needed the tracks much.With the old harvester, the tracks were used80% of the time. One of the key criteria isthe treadmarks left by the machine in thewoods: the lower surface pressure of theeight-wheeler makes working easier alsoin this respect.Frédéric confirms that the size of theharvester is a definite plus when movingaround the sites that have been thinned forthe first and second time. The manoeuvrabilityimproved by the increased tractiveforce manifests itself especially in wetlands.Due to the eight wheels and the balancingmechanism of the bogies, its slopeproperties are good, regardless of the foresttype. The driver's Sit Right seat adapts tothe body movements. Frédéric wears theseat belt under all conditions.Frédéric Foucault was mostly impressedby the C4 crane of the eight-wheel Ergo.The fast and efficient C4 complements theperformance of the H7 harvester head perfectly.The sliding boom with its ten-metrereach comes out quickly, which speeds upthe work stages. The operating comfort hasbeen further improved as a result of theunforeseen stability. The machine has notendency to fall, even if the grapple grabs alarge tree of more than four cubic metres.Thanks to the crane tilt, which turns 30 degrees,there is no need to force the grapplemovements. The operation of the harvesterhead is also facilitated by the 228 kNm lift-6Ponsse <strong>News</strong> 1 • <strong>2011</strong>
Hardware, sofTware and serviceing power, 280° turning angle, and 35 kNmslewing power.The H7 harvester head enables extremelyfast working: this is mostly affected by thefeed speed that is adjusted to each work stage,as well as the pinching force that varies accordingto the trunk diameter. "I was completelyamazed by the harvester head's operatingspeed," Frédéric admits. He uses a feedspeed of 5 m/s and controls all the cuttingand delimbing stagesmanually. The output,for example, ina spruce forest that isthinned for the secondtime is 24 m 3 per hour,and the maximum dailyoutput is 253 m 3 . According to Frédéric, heis now working more efficiently than before.The daily output increases by about one thirdduring first thinning, and undoubtedly evenmore during the second. The machine is extremelyproductive with its 16-litre (4.2 gal)hourly consumption. This can be seen duringits operation. The crane moves quickly to thetree butt, and the easily controlled harvesterhead rotates around the tree trunk until thebest cutting angle is identified. The crane liftsthe tree, and feeding is started. The adjacenttrees are barely touched. The rotation speedof the motor does not decrease during trunkprocessing, and before you know it, the craneis on its way to cut the next tree.The 8w model is 8,055 mm (317 in) longand 2,840–3,100 mm (112-122 in) wide. Themachine equipped with the narrowest tireis sufficiently agile for thinning, but the thenarrowness does not significantly weakenthe machine's stability. For operation onsoft terrain and steep slopes, Ergo 8w canbe equipped with suitable tracks and chainsto ensure unbeatable tire grip and machinestability.The eight-wheel model is naturally somewhatbigger than its six-wheel counterpartdue to its additional tires, bogie and a slightlylonger frame. However, the differences in theactual working condition remain small and,with regard to the effects on the terrain, theeight-wheeler's extremely low surface pressureensures superior performance.Both Ergos use the same six-cylinder 205kW (275 hp) Mercedes-Benz engine with anoutput 1100 Nm and a dual circuit hydraulicsystem. The tractive force of the <strong>PONSSE</strong> Ergo8w has been increased by 14% from the sixwheelversion to ensure its operation in thethe most demanding of conditions."I was completelyamazed by the harvesterhead's operating speed."The dual circuit hydraulic system of bothmodels guarantees that the machine will notrun out of power even in heavy-duty operations.A separate 190 cm 3 (11.6 in 3 ) workingpump is provided for the harvester head, anda 145 cm 3 (8.8 in 3 ) pump for the crane.The harvester climbs theslopes efficiently andturns in place.TESTEd ON ThE SlOPESThis is not the first Ponsse machine for Arnaud,a company located in Haute-Vienne.<strong>In</strong> fact, Arnaud was amongthe first customers and usersin France during a periodwhen Ponsse was not yetrepresented in France. Thecompany has experience alsowith Ponsse's earlier harvestermodels. Now the company chose theErgo 8w especially for sloping sites. ChristopheArnaud operates his new harvester andspecifies his selection criteria. He chose the8w due to its high performance, applicabilityto slopes and economic efficiency. With thisin mind, eight wheels constitute a significantadvantage.Christophe is already familiar with mechanisedharvesting on steep slopes. Eventhough the terrain in Limousin is not as famousas the slopes of the Alps, it is just asdiverse and dangerous at points. The sizeand location of certain wood lots require precisecontrollability. Christophe has masteredthe Ponsse machines well. When I ask himabout the good qualities of 8w, he replies "incrediblestability",without hesitation.Christophe admitsthat he recognisedcertain features ofErgo 8w. Accordingto him, already thesix-wheel version felt incredibly stable.As the interview starts, Christophe headsdirectly to the slope. The agility of the machinewas not affected even by the steepestof tilts. These typical and familiar conditionsused to make working considerably morecomplicated. The interviewee is very experiencedin working on sloping sites. Accordingto this forest machine entrepreneur, it makesno difference if the machine is going up ordown the slope. He knows how to utilise themachine's stability effectively. Previously, twotree belts could be processed when workingon a steep slope, and now three is no problem.It should be noted that Christophe'smachine does not have balanced bogies. Hethinks that they are unnecessary, as the machinewill turn before the bogies rise off theground. This, if anything, strengthens Christophe'simpressions of the behaviour of theharvester. He has selected the 710 tire size,but has not filled the tire with water as hedid with his six-wheel harvester. <strong>In</strong> the sixwheelversion, filling the tire with salt waterwas necessary.The harvester climbs the slopes efficientlyand turns in place. These are practical propertiesalso on this steeply sloping site, whichis located partly on a forest road. The machinelooks small in front of the over 20-metreDouglas spruces. The 8w model enablesharvesting over wide areas without additionalloading. Approaching the trees is considerablyeasier, the cutting and processing stagesfollow each other almost at the same pace aswhen working on even terrain.<strong>In</strong> terms of the crane, Christophe has onlypositive things to say about the new developmentsteps. Power is, of course, one of thefactors. Another is the crane tilt, which extendslonger in the front. He also remembersto mention the fact that the crane is installedon a pivot cylinder instead of a toothed rack.To top it all off, Christophe thinks that thereach has also improved.Regarding the harvester head, Christophevalues the great opening range of the rollersand knives. He has been able to process atrunk with a 92 cm (36 in) thick butt. The operatingspeed, 5.2 m/s with small trunks and4.5–4.8 m/s on large ones, is also appreciated.The harvester head neverjams – a feature that is trulybeneficial when delimbingover 14-metre logs. The combinedeffect of the torque andproportioned speed exceedsthe expectations of even themost seasoned user familiar with the brand,and the change to the old H73 model is remarkable.Furthermore, Christophe comments onthe design of the front end of the machineframe: it can now manage the steepest ofslopes. The cabin, which is located lowerthan in the Ergo 6w, is handy on slopes, eventhough the fuel tank cover decreases the visibilityof the front wheel to a certain extent.The Ergo 8w has been selling well inFrance. The 8w was not designed solely forsloping sites, but it overcomes both challengeswith ease: as an eight-wheeler it has alower surface pressure and guarantees morecomfortable operation.Ponsse <strong>News</strong> 1 • <strong>2011</strong> 7
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