Flail mower PTO RPM - margin of power

[PxP]

My decision what to buy/select on hold now.
Drove with my tractor to nearby New Holland dealer - they have also KUHN flail mowers - similar to one I want buy.
Wanted to check if it will work - 540 gearbox>1000 PTO.
It turned out my tractor front PTO is damaged (I never used it earlier - tho my tractor is 4 yrs old) :-(
When it will be fixed - I`ll check.

 

[Xfaxman]

No clue, but am interested in why you want to use a flail on the front instead of the rear which is more of the standard and more flexible with other tractor usage?
----------------

Since he didn't answer, my guess is he is mowing a vineyard or orchard, since it is a narrow tractor.

My other guess is that you have never mowed with a machine with an out front deck:

 

[Industrial Toys]

I saw a Kuhn at a friends place. It looked identical to my Perfect mower. I was going to look into it further next time I need knives/hammers.

Knives and hammers I can get anytime, but other stuff gets ordered from Europe once a year in a container.

 

[PxP]

>I am interested in why you want to use a flail on the front instead of the rear which is more of the standard and more flexible with other tractor usage?

When chopping branches from winter/summer pruning in orchard with flail mower at back - it quite often happens that apple tree branches pierce tires.
No such problem when flail mower at front.


Regards.

 

[PxP]

Tried today KUHN flail shredder BKE 180 REV with New Holland tractor (75HP) - mounted at front.
It worked ok - chopping 2-3 cm dia. branches. I`ve driven quite slow though.
Worked with 75HP - will work with 100HP.

Regards.

 

[SPYDERLK]

My decision what to buy/select on hold now.
Drove with my tractor to nearby New Holland dealer - they have also KUHN flail mowers - similar to one I want buy.
Wanted to check if it will work - 540 gearbox>1000 PTO.
It turned out my tractor front PTO is damaged (I never used it earlier - tho my tractor is 4 yrs old) :-(
When it will be fixed - I`ll check.

... OK, on hold
,,,,,,Re your orig question/decision point - At 1/2 rated rpm your tractor puts out less than half its rated HP. If torque stayed constant as rpm dropped you would have 1/4 the rated hp at half the rated rpm speed. -- BUT, torque of our diesels is not quite constant and maxes out well below power peak. From power peak, it rises slowly as rpm drops. The peak T is usually around 1700 rpm. Thats the sweet spot you want to be near. With 540 @ 1300 youre essentially falling off the bottom, and 25% of peak power is probably about right.

The 750 RPM implement gearbox should work nicely for your 1000 RPM PTO situation on the big engine. --- But wont be so good for the little tractors. :confused3:​

 

[sdef]

Since he didn't answer, my guess is he is mowing a vineyard or orchard, since it is a narrow tractor.
My other guess is that you have never mowed with a machine with an out front deck.

Yes, you are correct. I do understand the virtues of the mower type you posted. However, a 97 HP tractor is a different piece of equipment altogether. I have never performed large scale mowing requiring a 97 HP tractor with a front mounted mower, which is why I asked for specifics. My mind is still searching for the type of operation requiring something like this or how a front mount would be better than a rear mount on a tractor such as this with the PTO RPM mentioned and mower speed modification required. Just a learning experience for me.

Or maybe the OP just wants what he wants, which I can certainly relate to as I do similar sometimes .

 

[motownbrowne]

Yes, you are correct. I do understand the virtues of the mower type you posted. However, a 97 HP tractor is a different piece of equipment altogether. I have never performed large scale mowing requiring a 97 HP tractor with a front mounted mower, which is why I asked for specifics. My mind is still searching for the type of operation requiring something like this or how a front mount would be better than a rear mount on a tractor such as this with the PTO RPM mentioned and mower speed modification required. Just a learning experience for me.

Or maybe the OP just wants what he wants, which I can certainly relate to as I do similar sometimes .

Makes perfect sense to me. He's mowing/mulching prunings from orchards. Material like that sucks to drive over. It gets tangled up under tractors and ends up tearing off hydraulic lines, etc. By mowing before driving over the material you eliminate that problem. You clear yourself a path so to speak.

To the OP, personally, I'd much rather run the tractor at higher RPMs. That's what it's made for. That's where the HP is, that's where the oil flow and coolant flow is optimized for long term use.

 

[PxP]

... OK, on hold
,,,,,,Re your orig question/decision point - At 1/2 rated rpm your tractor puts out less than half its rated HP. If torque stayed constant as rpm dropped you would have 1/4 the rated hp at half the rated rpm speed. -- BUT, torque of our diesels is not quite constant and maxes out well below power peak. From power peak, it rises slowly as rpm drops. The peak T is usually around 1700 rpm. Thats the sweet spot you want to be near. With 540 @ 1300 youre essentially falling off the bottom, and 25% of peak power is probably about right.

The 750 RPM implement gearbox should work nicely for your 1000 RPM PTO situation on the big engine. --- But wont be so good for the little tractors. :confused3:​

Actually peak torgue in my NH is at... 1300 RPM - same RPMs as I want to work combined with flail chopper 1000@540 RPM PTO.
Max. torque ISO TR14396 (Nm@rpm) - 398@1300
Rated engine speed (rpm) - 2300

As I wrote earier - 75HP tractor worked ok 1000@540 RPM PTO with KUHN flail chopper. My NH got 25% more power and better torq. at lower engine RPM.

Flail mower I want to buy and front/back config. of it:

 

[buickanddeere]

Need more reserve power than what the 1/2 speed gearbox allows. How expensive are these gear boxes ?