Rotary Cutter Bush hog hp requirements

[Farmwithjunk]

How many here have actually bogged down a rotary cutter? I've read tht 5 HP per foot "rule" for quite a while, but have read of few folks that had issues with their cutters.
First year I had my 5' cutter, it was operated behind a 16 PTO HP tractor. That's less the 4 PTO HP per foot. I had no problems...just use common sense when you operate the unit.

That'd be me. But that's at 5-1/2 to 6 mph mowing wide open flat fields of 3' to 4' tall fescue/weeds. (Done so with several tractors, one where I was running almost 10 hp per ft.)

At normal, slower (read SENSABLE) speeds, I've seen 17 hp with a 6'er do ok.

 

[jbrumberg]

I agree with RoyJackson and Farmwithjunk (as usual ). I have managed to rotary cut some pretty nasty vegetation including ~2" softwood (poplar) saplings with
~4 PTO HP per foot. The "Compact Tractor Bible (2006)" for what its worth states: "The power (requirements) is typically 2 HP per foot of cut for light-duty rotary mowing and 5 HP per foot of cut for brush hogs capable of smashing 2" diameter saplings". The most demanding cutting I have done is ~7A's with 11 PTO HP (Ford 1100) running a 3.3' (Woods M-40) RC and I was cutting 5' - 6' weeds and a lot of ~2" saplings when we bought our property many years ago. I did bog down and stall the tractor on occassion (going too fast) but I was able to cut everything. I will state that I finally killed that RC . Common sense is the key. Jay

 

[greg_g]

How many here have actually bogged down a rotary cutter? .

Me. My Jinmas had 21.5 PTO hp and aggravated the **** outa me with a five footer. I figure I could have mowed an equal number of acres/hour with a four footer, simply cuz the five footer required such slow ground speed.

My KM454 has ~39 PTO hp, and I've slowed a six footer down some in the occasional long wet stuff. But overall it doubles the acres/hour I could do with the Jinma.

My TS354C has ~30 PTO hp, and handles a five footer just fine in all conditions. This is my first summer with it, but it hasn't bogged down yet.

My experience definitely supports the 5hp rule.

//greg//

 

[Soundguy]

Hmm.. I've had to run WOT on my 8n to pull 5' cutter thru 5-6' weeds.. but I guess it ran pretty good. This was 2nd gear inthe 5' stuff.. and 1'st gear in the 6' stuff... was just barely able to keep 540 pto rpm with throttle at max.. good thing it wasn't 6.5' or I'd had to take a 4' bite I think!

I've found that lush thick green grass is much more of a load than tall stemmy weeds that are 2x to 3x as tall as the grass...

Soundguy

 

[JoeinTX]

"I've found that lush thick green grass is much more of a load than tall stemmy weeds that are 2x to 3x as tall as the grass..."

Yeah, agree for the most part.


For the poster, he is at the outer limits of what his rig can do in normal conditions. 26hp to 6'...........okay in moderate conditions but will require a partial swath in thick and thorny areas and additional weight up front to handle the load.


Invader grass/weeds and the odd small tree or bush are easier to handle thank consistent healthy grass growth when cutting.

 

[JerryG]

I have bogged down several tractors with a mower. Tall fescue with thick undergrowth as well as when mowing bermuda. Nothing is as hard to mow fast as bermuda.

 

[Farmwithjunk]

I have bogged down several tractors with a mower. Tall fescue with thick undergrowth as well as when mowing bermuda. Nothing is as hard to mow fast as bermuda.

YEP! One of my pastures has a patch of bermuda about 100' X 200'. Even if I'm only cutting a couple inches, you can hear the tractor laboring as I pass through it. Tough stuff to get rid of too.

 

[wolc123]

I can relate to soundguy's post. My 8n did not do so good on thick grass with a 5ft bush-hog squealer. Had to run wide open, 1st gear and take a partial cut. The Ford 2000 diesel I replaced it with handled this cutter with ease. The n's just seemed weak thru the pto but it was equal to or better than the 2000 pulling a plow so it certainly had no problem applying the drawbar hp.

 

[RoyJackson]

Boy...I just slow down a bit...other then a few seconds waiting for the engine to catch up...can't say I've ever had a problem.
Now, due to the terrain, I do go slow (2nd gear which is..maybe 1.5 MPH) and on some sections, 3rd low (2.5-3 MPH).

 

[Nick Danger]

Based on my experience to date I think this is a good rule of thumb. I have 8 PTO hp per foot (6 ft cutter and 47 PTO hp) and I find that this setup is massively overpowered.

If you had a hair on your... you'd realize you can NEVER be "massively overpowered"... :thumbsup:

As I leave, Tim Allen's warcry playing in my head...

 

[Soundguy]

I dunno, before I got a 15' batwing, I ran a 10' mower behind my 7610s, at about 9 hp per foot, it seemed like there was always 2-3 to spare.. Per foot..

 

[Turbys_1700]

I dunno, before I got a 15' batwing, I ran a 10' mower behind my 7610s, at about 9 hp per foot, it seemed like there was always 2-3 to spare.. Per foot..

Those 7610's are absolute beasts Soundguy...
You know that first hand...

 

[Soundguy]

I love mine. Considering putting the 10 back on it to make tighter turns.

 

[RalphVa]

The 5 hp/ft rule sounds good to me. I had an 18.5 hp JD 4010 with 4 ft brush hog. It was fine, even hood high grass but would bog on sand and really thick, less tall, grass. I've a 24.5 hp JD 2025R now with a 4 ft brush hog. I run it at only 2500 rpm vs. about 3000 for PT speed, and it bogs at about the same stuff as the 4010 did. I just know that I really don't need more than about 20 hp, and the 2025 @ 2500 rpm probably gives me about that. Used to run the lemony 1025R with 23.5 hp at its PTO speed. Could tell it had a bit more oomph, as would the 2025 if I ran it up to PTO speed. I just don't like to use too much fuel.

Ralph

 

[Turbys_1700]

The 5 hp/ft rule sounds good to me. I had an 18.5 hp JD 4010 with 4 ft brush hog. It was fine, even hood high grass but would bog on sand and really thick, less tall, grass. I've a 24.5 hp JD 2025R now with a 4 ft brush hog. I run it at only 2500 rpm vs. about 3000 for PT speed, and it bogs at about the same stuff as the 4010 did. I just know that I really don't need more than about 20 hp, and the 2025 @ 2500 rpm probably gives me about that. Used to run the lemony 1025R with 23.5 hp at its PTO speed. Could tell it had a bit more oomph, as would the 2025 if I ran it up to PTO speed. I just don't like to use too much fuel.

Ralph

That 5 HP per foot rule is pretty accurate. My 4610 Ford pulls my 6 foot Brown cutter easily through pretty much anything I can run over. It has 52 HP. I would like to find a good 8 or 10 foot pull cutter to run behind it.

 

[MESSMAKER]

I mow with about 4hp per foot. I can mow anything in low range. I mow 95% of the time in mid range and only struggle when I run into really thick grass or scary steep hills.

 

[Cranedaddy]

I'll second a lot of this. I have 29 PTO hp and a 5' cutter. I've never bogged down my tractor. I've tried, running in medium range pedal to the metal in thick 2' tall wet grass. Really really wish I had got the 6' cutter.

 

[Rickyc]

I'll second a lot of this. I have 29 PTO hp and a 5' cutter. I've never bogged down my tractor. I've tried, running in medium range pedal to the metal in thick 2' tall wet grass. Really really wish I had got the 6' cutter.

I've always heard 5 per ft as well.
I have a Woods BB60 and BB72.... PTO is rated 27 or 28. In overgrown pasture even in Low range by anti-stall will kick in and I come to a stop WAY too often and going to pull the trigger on a John Deere 5075 or 5085 as wanting to go to maybe the Woods BW12. Largest of woody saplings (not thick..mostly grasses and some blackberry) is about 1" or less.
Not sure how Woods is saying a BW12 can operate on 35 HP PTO.
My feelings, the more PTO HP the better unless you dont use common sense and over load the gear box in too heavy of brush.
Also need mention...my fields are hilly and ANY up-hill is where the problem arises so think not only the Required PTO HP but the weight and terrain all come into play big time.

 

[WoodChuckDad]

I'm running a Kioti 7320 with 63 Hp at the PTO. I feel like I have enough HP for most brush hogs. I'm wondering about width. My tractor is 7 feet wide. Should I not even consider less than 7 feet?

 

[Soundguy]

get an 8' twin spindle.. they are lighter, don't stick out the back as far, and are just generally easier to run that a single spindle 7' mower.