Tiger in the tank

Tiger­cat 632E tested

New Zealand Logger - - Front Page - Story: John El­le­gard Pho­tos: John El­le­gard & Aaron Gre­gan

now he’s first with the 632E.

Bit of a theme go­ing on here, Kevin? “Yes, he laughs, “I guess I must be their skid­der guinea-pig.”

Ei­ther that, or he’s quick to spot a suc­cess­ful ma­chine in the mak­ing.

Kevin first laid eyes on the 632E when vis­it­ing the Tiger­cat fac­tory in Canada last year, then saw it again at the DEMO Show in Bri­tish Columbia, which con­vinced him it was the skid­der for his op­er­a­tion.

DK Log­ging was still run­ning the orig­i­nal 635C, but it was get­ting up around 16,000 hours and Kevin wasn’t sure a six-wheeler was nec­es­sary for where his crew is work­ing on the eastern flanks of Tarawera For­est, off the McKee Road (aka the Mil­lion Dol­lar High­way).

“The rea­son we went with this ma­chine and not a six-wheeler is we shovel a lot down­hill any­way and the six-wheeler it’s prob­a­bly a bit over the top if you are not get­ting up on the ridges and that,” says Kevin.

“Thought I’d go with a four, a bit faster. This one’s got the big grap­ple, the 23-square me­tre, so not far off the six-wheeler’s 25-square me­tres, and the 630 has the 19, so this one is a bit more than in-be­tween.

“I was plan­ning on a 630E but when I got to the fac­tory th­ese things were sit­ting there, so …………

“This one can pull at least a cou­ple of tonnes more. And it does it faster. It will pull a drag that makes the tyres look as though they are flat.”

Each of those Tiger­cat skid­der mod­els is very closely re­lated, as both the 635 and 632 are de­rived from the 630. The 635 is ba­si­cally the 630 with an ex­tra axle tacked onto the rear, whilst the 632 uses the same ar­chi­tec­ture as the 630, but has been pumped up on steroids.

Sev­eral com­po­nents and struc­tural items on the 632E have been up­sized for im­proved dura­bil­ity so that it can cope with the ex­tra work­load. Ex­am­ples are a larger and beefier crane and arch, big­ger box sec­tions in the chas­sis, heavy-duty cen­tre pivot and larger sup­port­ing arms for the blade. And, of course, that big­ger grap­ple. All up, the changes add a fur­ther 1.865 tonnes to the weight, com­pared to the 630E.

Walk­ing around his new “beast”, Kevin points out some of his favourite changes, such as the en­larged grille in the arch, which is both deeper and wider, to af­ford the op­er­a­tor a bet­ter view of stems on the ground as he guides the grap­ple to them. There’s a new light built into the cen­tre of the arch, in ad­di­tion to two al­ready there, for im­proved vi­sion in early morn­ing starts (all lights are now LED).

He pats the grap­ple, which looks a lot big­ger up close, happy that he went with this size. Tiger­cat had the lux­ury of see­ing what Cater­pil­lar and John Deere had done with their grap­ples be­fore re­leas­ing the 632E and they ob­vi­ously couldn’t re­sist go­ing for brag­ging rights by mak­ing their one slightly larger. You can get a smaller grap­ple, but hon­estly, why would you? This one can swal­low 2.14 m2 (23 ft2) of wood, and when fully open, it stretches out to 3,861mm tip-to-tip, so it can be an ab­so­lute Gan­net. It’s op­er­ated by a pair of hefty cylin­ders and comes with a choice of plate or box tongs – Kevin took the plate op­tion.

At the other end, the blade has also been su­per-sized, with ex­tra ex­ten­sions built on ei­ther side be­cause the Tiger­cat team knows Kiwi log­gers like their big blades. They also had the good sense to in­crease the size of the pis­tons that work the blade.

You need a pow­er­ful en­gine to move a near 22-tonne ma­chine and 16-plus tonnes of wood, and Tiger­cat has hap­pily obliged.

Tiger­cat has been pro­gres­sively re­plac­ing the pre­vi­ous Cummings en­gines across its range of equip­ment with a line of FPT en­gines – FPT is part of the Fiat In­dus­trial group. The 6.7-litre six-cylin­der FPT N67 en­gine fit­ted to the 632E may be smaller in cu­bic ca­pac­ity than its di­rect com­peti­tors – 7 litres for the Cat 555D and 9 litres in the John Deere 948L – but it’s the most pow­er­ful of the three, with peak out­put di­alled up to 216kW (290hp) @ 2,000rpm, from 195kW (262hp) in the 630E. It’s still a Tier 2 en­gine like the John Deere’s, so it isn’t as clean as the Cat Tier 4f unit, which may be an im­por­tant con­sid­er­a­tion to en­vi­ron­men­tally-con­scious con­trac­tors.

Peak power is only one as­pect of per­for­mance mea­sure, how­ever. It would be nice to know what the torque out­put is, but no fig­ures are given. I’m guess­ing that it will be closer to the Cat’s 992Nm, rather than the John Deere’s 1,276Nm, given the size of the en­gine.

What­ever the torque fig­ure is, Tiger­cat seems to have wran­gled ev­ery New­ton me­tre from the N67 to ram through the EHS drive sys­tem, be­cause the per­for­mance is some­thing else.

EHS, or Ef­fi­cient High Speed, might best be de­scribed as a hy­per-ac­tive hy­dro­static drive sys­tem. Tiger­cat has used stan­dard hy­dro­static drive for more than 20 years and the EHS sim­i­larly con­sists of two vari­able dis­place­ment mo­tors as in­puts to the Tiger­cat trans­fer case, with front and rear out­put shafts con­nected di­rectly to the front and rear axles.

While the stan­dard elec­tron­i­cally con­trolled hy­dro­static drive sys­tem per­forms ex­cep­tion­ally well, EHS al­lows it to do more, thanks to a bit of ex­tra tech­nol­ogy.

This is ac­com­plished with more so­phis­ti­cated com­puter logic and the abil­ity to take one of the drive mo­tors off­line when high trac­tive ef­fort is not re­quired — for in­stance, when trav­el­ing empty or loaded on flat ter­rain. In this case, all pump flow is di­rected to one hy­draulic mo­tor, in­creas­ing both travel speed and mo­tor ef­fi­ciency.

When op­er­at­ing con­di­tions de­mand high trac­tive ef­fort, such as pulling a heavy drag, both hy­dro­static mo­tors are work­ing. Com­pli­cated? Maybe. Ef­fec­tive? Yes.

With so much power di­rected to the ground, it’s im­por­tant the driv­e­line com­po­nents are able to with­stand the ad­di­tional forces

The new OB20 rear axle – spe­cially de­signed for the 632E and the big­gest sized axle in any skid­der — pro­vides 47% more torque ca­pac­ity and nearly twice the life on all bear­ings. The ser­vice brakes and park brake are in­cor­po­rated into the new axle.

The axle mount­ing has been re­designed to use four high-strength 30mm bolts and two 30mm studs on each side, mounted to a mas­sive 77mm thick steel frame. The new de­sign trans­fers the force to the skid­der chas­sis and can bet­ter han­dle the higher torque load of the new axle and up­rated EHS drive. Rear drive shafts have been in­creased in size to 8.5C from 7C.

As men­tioned at the very start of this ar­ti­cle, we couldn’t help but be im­pressed with how the 632E gets into its work. Charg­ing around the skid site like a ma­chine half its size, then belt­ing back up to the cut-over at a sur­pris­ing speed, con­sid­er­ing it was trav­el­ling up­hill. Re-ap­pear­ing a cou­ple of min­utes later with a heavy drag be­hind, yet still run­ning like an ex­press train. Eas­ily faster than any for­warder we’ve seen, which are sup­posed to be the race horses of wood trans­port­ing in the for­est.

Reg­u­lar op­er­a­tor Rick Royal reck­ons he can pull as much wood as the old 635C he was driv­ing be­fore jump­ing into this ma­chine. I re­call that when we tested that 635C in 2008, in an­other part of Tarawera For­est, it was drag­ging as much as 20 tonnes on oc­ca­sions.

Rick says the 632E is ca­pa­ble of pulling that much, but he doesn’t feel it’s nec­es­sary to put it un­der so much strain. Pulling lighter loads (around 16 tonnes) at higher speed de­liv­ers faster turn­arounds, mean­ing he can still hit the 750-tonne daily av­er­age.

“That’s a big grap­ple and I’ve had six real big stems in there, some would have been around three or four tonnes each, but you don’t want to be pulling that much all the time,” Rick adds.

“Com­pared to a 630D the drags are big­ger and a lot quicker – it prob­a­bly takes two ex­tra stems per drag and it does that eas­ily.”

He’s driven a few Tiger­cat skid­ders in al­most ten years with DK Log­ging, in­clud­ing the first 630D, which is a good ref­er­ence point for the 632E.

“This one has more power than the 630D,” says Rick. “Lot more weight, it doesn’t come off the ground very easy. I like that.

“The 635 is pretty weighty too, that was good. The six wheels make a big dif­fer­ence on wet ground but I’m sur­prised with the trac­tion on this one – we haven’t needed to think about chains yet.

“It’s bet­ter on the fuel than the 635. That had a smaller tank and

we filled it ev­ery day. I’m fill­ing up the 632E ev­ery one-and-a-half days and it still has a third of a tank left. Pretty good when you con­sider this tank is 430 litres – less than the 630D, which has a 500 litre tank, I think. The tank has been re­duced in this one so you can see bet­ter down over the arch.”

Rick says the ride in the 632E is com­pa­ra­ble to, or slightly bet­ter than the 630D, but not as smooth as the six-wheeled 635. It does, how­ever, make up for it with im­proved ma­noeu­vra­bil­ity over the six-wheeler.

For Rick, some of the big­gest im­prove­ments are in the cab. The ar­chi­tec­ture hasn’t changed – it still uses the same cab struc­ture as be­fore – but key im­prove­ments have been made for com­fort and drive­abil­ity.

Top of the list of im­prove­ments is the new air-ride Turn­Around seat, ac­cord­ing to Rick.

“It’s real good, much bet­ter than I was used to in the 635, which wasn’t even Turn­Around,” he says. “Com­pared to the 630D it’s bet­ter. Very com­fort­able and has lots of ad­just­ments you can make to it. Has the 4-point har­ness, too.

“The ig­ni­tion has been moved to over by the rear-side win­dow. Used to be un­der the dash. Some­times I go to reach un­der the dash and it’s not there. I’ll get used to it.”

Steer­ing is now through joy­stick con­trols, com­pared to the wheel on the 635 Rick came off, al­though he did have joy­sticks on the 630D prior to go­ing onto the six-wheeler.

A new instrument panel lay­out im­proves place­ment of elec­tri­cal out­lets and the elec­tronic con­trol sys­tem dis­play.

Com­pared to his pre­vi­ous ex­pe­ri­ence with the 630D, Rick has no­ticed some dif­fer­ences in the speed con­trols, say­ing: “On the left­hand joy­stick, where you’ve got for­ward and re­verse – in the old one, you could just slide it and it would stay in po­si­tion on the track. This one, you just flick it and it will go down.

“It starts off at about 5 and then goes to 10, 15, 20, 30, 40, 50, 60, 80 up to 100. That’s per­cent­age not km/h. But, boy, this ma­chine can move. If you got a good bunch of pulp in it you could shift it to 100 (per­cent) to go down the road and it would re­ally go. I’ve pulled good drags at 80 (per­cent).

“There is an ex­tra but­ton on the joy­stick trig­ger, that’s to make the ma­chine drive in­stead of us­ing the ped­als. If you are go­ing down the road you just pull the trig­ger and away you go – so you can give your foot a rest. It’s quite touchy. It doesn’t take much to ad­just the speed.”

Since Rick swapped into the 632E from the old six-wheeler, his col­leagues have no­ticed the dif­fer­ence.

“It’s got a fast turn­around, that’s what the har­vester op­er­a­tors reckon,” he says. “They say it’s that fast they can’t keep up. Lot faster than the six-wheeler.”

Rick likes the fact that the 632E is equally fast when driv­ing in re­verse, adding: “The good thing is you don’t have to turn­around when you’ve dropped the stems at the skid, you can just keep go­ing grap­ple first. Saves a bit of time.”

With the ad­di­tional vis­i­bil­ity through the arch, Rick says he doesn’t have any prob­lems see­ing the track ahead when re­vers­ing back to the cut-over. And the ex­tra depth in the grille makes a big dif­fer­ence when he’s ma­noeu­vring to grab stems.

“I can see a lot bet­ter through that new grille, it means I can get closer to the stems and still see,” he says.

“The longer boom makes it eas­ier to reach, too.”

That ex­tra length in the boom al­lows Rick to raise the butt ends higher, so there’s less of the trees be­ing dragged on the ground – an­other rea­son why this ma­chine is so quick.

And yet, in spite of the ad­di­tional bulk of the boom and the grap­ple they are also just as fast to work as the rest of the ma­chine.

“The hy­draulics are prob­a­bly five times faster than be­fore,” chips in Kevin.

There’s a rea­son for that. The hy­draulic sys­tem has un­der­gone some big changes, the most im­por­tant of th­ese be­ing a move to load-sens­ing, along with a larger main hy­draulic pump and valves, al­low­ing for bet­ter mul­ti­func­tion­ing. The larger hy­draulic cylin­ders en­able the ma­chine to run pres­sures that are 10% lower while

in­creas­ing per­for­mance.

This as­pect im­pressed our Iron Tester, Stan Bar­low, when he got be­hind the con­trols, and you can read his com­ments on page 34.

Be­fore we let Stan loose on the Tiger­cat, we ask Rick whether the move from HID light­ing to the new LED lamps (there’s 11 of them) has been a pos­i­tive one for those early morn­ing starts.

“They’re pretty good, nice and bright on dark morn­ings, pretty much the same bright­ness as the HIDs in the old skid­der,” he says. “They don’t suck as much power, so that’s good.

“The new po­si­tion of the lights on the boom – they’ve moved right to the front – and that new light in the mid­dle, has made a big dif­fer­ence. Lights the grap­ple up nicely in the dark.”

We leave Rick to give Stan some point­ers on the con­trols of the 632E, in prepa­ra­tion for his Iron Test, while Kevin and my­self chat about har­vest­ing in this part of Tarawera For­est.

DK Log­ging has been work­ing in Tarawera for a while, so Kevin and the crew are well versed in the ter­rain and var­ied ground con­di­tions. Even though this is largely ground base coun­try, some of the hills can be very chal­leng­ing to pull wood from, Kevin says. And the ground con­di­tions vary wildly within the for­est, from free-drain­ing pumice to pock­ets of boggy clay.

I men­tion to Kevin that Stan and I en­coun­tered some of that sticky stuff when we took a wrong turn and ended up at their pre­vi­ous skid site, just around the cor­ner.

“The ground con­di­tions were re­ally bad in there,” nods Kevin, “but this skid­der was pulling the wood al­right. We haven’t needed to put chains on it yet, seems to be get­ting through with­out them. We’ll see how it goes when we get some more rain (note: more rain did ar­rive, but not enough to re­quire chains).”

Keep­ing those 35.5 x 32 tyres off chains for as long as pos­si­ble will help to pro­long their life, too.

To be fair, this new block, where they started a few days ear­lier, does look nicer than the one we stum­bled into and it doesn’t have any stand­ing wa­ter. That’s been very help­ful in en­abling the new Tiger­cat keep up its speedy work rate.

We’re now about to see whether Stan can match the pace of Rick be­hind the con­trols of the 632E, as he’s set off for the cut-over to grab his first stems.

Stan has wide ex­pe­ri­ence on skid­ders, but con­fided ear­lier that this is the first modern Tiger­cat he’s driven with a Turn­Around seat and among the few he has steered through joy­stick con­trols. Hav­ing watched how well Rich per­formed, Stan was anx­ious that he didn’t let the side down.

Maybe that’s why he reap­peared on the skid a short time later with a grap­ple bulging with wood, as he tried to em­u­late Rick, drop­ping a cou­ple of stems while turn­ing to­wards the stack. He later ad­mit­ted he should have been less greedy with his first load.

It took Stan a lit­tle while to find his rhythm, partly be­cause the steer­ing joy­stick on this ma­chine was in the op­po­site hand to the Ko­matsu for­warder we had been test­ing ear­lier in the day in the ad­join­ing Kain­garoa For­est.

But the 632E is a rel­a­tively sim­ple ma­chine to un­der­stand and Stan soon got the hang of it and was en­joy­ing the same speedy travel and im­ple­ment op­er­a­tion that we’d wit­nessed with Rick at the helm when we first ar­rived.

Rick has now joined our group, as we watch Stan doze the stems in to­wards the stack, and I ask whether he likes the big blade and how much use it gets, and he says: “It’s wider than what I had be­fore, very use­ful on the skid. I do use it a fair bit, scrap­ing the sur­face and clean­ing it up.”

The ex­ten­sion has added an­other 700mm to the over­all width of the blade, which is now al­most three me­tres, not far off the size of the blade on the John Deere.

“We didn’t ex­pect it to be that wide when it turned up like that from the fac­tory, but we’re not com­plain­ing – it saved us do­ing it here,” adds Kevin, as Stan ar­rives with his fi­nal load to com­plete this Iron Test.

It ap­pears to have been a speedy and seam­less trans­fer from the Big Six to the Big Four for the DK Log­ging team and Kevin agrees: “So far, so good.”

Maybe that should have been: “So fast, so good”.

Longer boom and re­vised arch can lift the stems higher off the ground.

Fac­ing page top left: Hills are no match for the power of the Tiger­cat 832E.

Fac­ing page top right: The DK Log­ging 632E runs stan­dard wheels and tyres, yet it hasn’t re­quired chains this wet win­ter.

Fac­ing bottom: Keep­ing those stems high off the ground is one of the se­crets to faster drags.

Right: Reg­u­lar op­er­a­tor, Rick Royal, could carry more stems in that big grap­ple, but doesn’t want to over­load the skid­der.

Above left: New LED light­ing around the top of the cab, and in the arch, im­proves vis­i­bil­ity on dark early morn­ing starts.

Above right: The DK Log­ging team pose with the new Tiger­cat 632E the day it was de­liv­ered.

Bottom: New instrument panel lay­out, re-po­si­tioned start but­ton and an up­graded air-sus­pen­sion seat are the big­gest changes in the cab.

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