Rotary Cutter Hydraulic GPM question for a rotary cutter on a Bobcat Toolcat 5600.

[theultimatetoolcat]

Hey guys,

Tried posting this in the toolcat forum, but didn't really get any bites. Hoping I'll get a bit more information posting here.

I've got a Bobcat Toolcat 5600 with the high flow hydraulics. Standard is 18.9 GPM, and high flow is 27.9. I'm interested in getting a Bobcat Brushcat rotary cutter for it. The oscillating deck really appeals to me for use on the piece of property I'll primarily utilize it on. Lots of rolling hills.

The 72" standard flow Brushcat has a minimum work flow of 15 GPM, and a maximum of 26 GPM.

The 72" high flow Brushcat has a minimum of 24 GPM, and maximum of 40.

The salesman was a little indirect and seemingly just trying to make a sale, and couldn't quite answer my questions.

Would I do damage to the standard flow brush cat by putting my machine in high flow and giving it more flow than it's requesting? If I went with the high flow, would it be supremely underpowered, only getting 27.9 GPM?

Hoping to clear this up before I make my decision. Any input would be appreciated.

Thanks!

 

[Harry in Ky]

Having never been near a Toolcat I don't feel qualified to comment on the machine or what it might be capable of physically or hydraulically. Basic hydraulics is another matter. My fourth grade math tells me the difference between 26 GPM and 27.9 is minimal at that stage. No doubt the spec is related to a specific engine RPM, so I would imagine if the machine ran 100 RPM below that the difference would be even less.

If I were faced with this I would lean toward the standard 26 GPM cutter and run it with the high flow option. Maybe keep the engine RPM at or slightly below the specified point. Certainly not exceeding it.

One man's opinion. Do with it as you wish.

 

[leonz]

Don't waste your money.

If he could not answer your question directly that is always a bad sign.

Do you have an add on oil cooler and external hydraulic tank for any attachments
that use hydraulic motors??

You have to remember that the hydraulic oil is going to get hot and hotter.

If the hydraulic motor on the mower does not have a case drain hose on the
hydraulic motor to relieve the hydraulic systems full pressure against the oil seal
on the motor shaft will be pushing against the hydraulic motor oil seal at all times.

For the money you would be better off just investing in a motorized RAMMY flail mower
and mounting it on the tool cat as it would mount the same way the flail mower would
mount on a ATV/RTV.

You could always invest in a Kunz towed motorized acrease 27 horsepower rotary cutter
with 5 high floatation tires and do that if all you are doing is just brush mowing as you
will spend less money and the tool cat will just be a 4 wheel drive tow vehicle.

Like I said, don't waste your money on the brush cat mower.

 

[theultimatetoolcat]

Don't waste your money.

If he could not answer your question directly that is always a bad sign.

Do you have an add on oil cooler and external hydraulic tank for any attachments
that use hydraulic motors??

You have to remember that the hydraulic oil is going to get hot and hotter.

If the hydraulic motor on the mower does not have a case drain hose on the
hydraulic motor to relieve the hydraulic systems full pressure against the oil seal
on the motor shaft will be pushing against the hydraulic motor oil seal at all times.

For the money you would be better off just investing in a motorized RAMMY flail mower
and mounting it on the tool cat as it would mount the same way the flail mower would
mount on a ATV/RTV.

You could always invest in a Kunz towed motorized acrease 27 horsepower rotary cutter
with 5 high floatation tires and do that if all you are doing is just brush mowing as you
will spend less money and the tool cat will just be a 4 wheel drive tow vehicle.

Like I said, don't waste your money on the brush cat mower.

Solid advice. No oil cooler or external tank. Sadly, I don't think the RAMMY flail mower, or Kunz unit would be able to handle the amount of land I'm trying to maintain.

But I'm willing to hear of other alternatives, or at least get to the bottom of my initial GPM question

 

[leonz]

The largest Kunz unit has a 27 horsepower air cooled motor.

The nice thing about it is that you can hook up 3 of the 57 inch mowers together to mow
almost 15 feet in one pass with one in the center and two on either side or one behind the
other to the left or right.

I candidly think once you see the videos of them mowing you will change your mind.

The Rammy flail mowers have the scoop knives and will cut thick brush just as the Kunz units will.

 

[leonz]

MASCHIO offers a new motorized towed flail shredder with cast hammer knives and a tow hitch.

If you call Cummings and Bricker in BATAVIA, NY who is the national MASCHIO importer you can find out more about them as they
have imported a bunch of them.

 

[ruffdog]

For the money you would be better off just investing in a motorized RAMMY flail mower
and mounting it on the tool cat as it would mount the same way the flail mower would
mount on a ATV/RTV.

I'm not sure that the Rammy could survive being run on the front of a 6000 lb machine. I don't think they are made to be attached to a skid steer. Yes, the Toolcat has a HD oil cooler and is approved by Bobcat to run the Brushcat.

 

[ruffdog]

Bobcat says the high flow version will add extra torque over the standard version. What are you cutting? Is it knee high or over head high? Weeds or heavy grass?

 

[oldnslo]

How is Bobcat controlling cutter speed over the flow range? Cutter speed is based on motor displacement vs flow unless there is some mechanical gearing change. So higher flow maintaining cutter speed equals larger displacement motor.
Displacement and pressure differential across the motor equal torque so larger displacement equals greater torque hence in theory the higher flow unit provides greater torque if indeed has higher displacement motor.

Some cutter heads have variable displacement motors so as pressure increases to a preset point the displacement increases to power through tough spots but cutter speed decreases until load induced pressure drops and cutter speeds back up.

I have no idea how BobCat units are made.

 

[theultimatetoolcat]

Bobcat says the high flow version will add extra torque over the standard version. What are you cutting? Is it knee high or over head high? Weeds or heavy grass?

I did notice that, but the standard also has a pretty noticeable jump on tip speed. Right now it's just chest high heavy grass. I plan on mowing it more frequently so it doesn't get as high as it is, but nothing beyond grass and the occasional small bush. Nothing close to that 3" diameter limit it states.

Dealer recommended me a high flow model, but was more just erring on the side of caution.