Acres cut per hour

[Barry Bowen]

12-15 inches tall is simply too tall for a finish mower if there is any thickness to it at all. If you want to do a crappy job, then use a finish mower. With that height you are better off with a bush hog type mower. I use a 12' Befco finish mower on my hay fields in the spring to trim them back about 2 or 3 inches, and 4 mph is very optimistic if you need to do a good job. If quality does not mater, balls to the wall and let stuff clog and break. Finish mowers are meant to cut lawns, ie cut off 2 or 3 inches not 12-15. Bush hog made a bat wing that had counter rotating blades on each spindle to mulch stuff up. Kind of rare to find, but it would do the job you want in one pass, but it takes better than 100 HP to run it right.

 

[Dargo]

builder

I haven't ever had one but it seems as if the woods 990 might be a good match for your needs. It is a finish mower but has free swinging blades like a hog. They are pricey though

Woods Equipment Company - RM990 series 90?

good luck

the wind

I've run one of those with 75 PTO HP for over 5 years with zero issues. The gearbox is rated for 75 hp. I set my PTO slip clutch to 40 hp and have only seen it slip once or twice. I've mowed anywhere from 12" or so to weekly 3" mowing that looks like a fairway. Without a doubt, the best mower for a bush hog/finish mower hybrid.

 

[LoneCowboy]

i agree, 18" tall grass is rotary cutter territory

then finish mow it after it's cut down to a reasonable length.

8' mower: 3 to 4 acres an hour

15' mower, 7 to 8 acres an hour

3mph for rotary cutting with a 70hp 8' is awful slow. I cut at 5mph with a 15' mower with 70 hp. 6mph when I had an 8' mower. (it would go faster, but it beat me up too bad going faster). (although, your grass may be thicker than it is here, but even in really thick thick wet grass I only gear down to about 4mph with the 15' rotary cutter and it plows right thru that.

 

[Builder]

i agree, 18" tall grass is rotary cutter territory

then finish mow it after it's cut down to a reasonable length.

8' mower: 3 to 4 acres an hour

15' mower, 7 to 8 acres an hour

3mph for rotary cutting with a 70hp 8' is awful slow. I cut at 5mph with a 15' mower with 70 hp. 6mph when I had an 8' mower. (it would go faster, but it beat me up too bad going faster). (although, your grass may be thicker than it is here, but even in really thick thick wet grass I only gear down to about 4mph with the 15' rotary cutter and it plows right thru that.

I think there's a lot of subjectivity to conditions here. When I hog, I'm going 3MPH. Some of my customers wait until weeds are 6-7' high and 1' thick. If I go faster I get windrows & stragglers. I don't like going over work twice. 3rd gear low range seems to be the sweet spot. 4th gear low leaves more than I like.
I think just the fact that you're able to use a 15' batwing with a 70HP tractor proves your cutting is lighter than mine. If I ran a 15' bat through the crap I have to cut, it would look bad. Now if I'm cutting 12-18" pasture grass, I can move faster and use 15' mower.

Can you get 12" tall grass to look like a lawn if you use a bush hog, not a finish mower?

 

[JWR]

Thanks FWJ. Anyone think 4MPH is a reasonable speed mowing 12-18" tall pasture grass with a 8' finish mower behind my M-7040?

I usually only do bush hogging. When I bush hog, I go ~3MPH with an 8' bush hog through 5' tall weeds, but it leaves some sticking up here & there.

According to my calculations. I should be able to cut 3.8 acres/hour at 4MPH w/ 8' finish mower. I would reduce that to 3 acres per hour to account for turns. So I should be able to mow 20 acres of light pasture in under 8 hours with a 8' finish mower if I run at 4MPH.

Sound plauseable?
I pretty much got the mowing contract, now I gotta find a big finish mower. Flail or finish is the next step.

A few comments:

1) Calculations will only give you a VERY rough idea. Cut it once and you'll know the truth of the matter.
2) Don't know what sort of finish mower you plan to use but let me mention:
a) Finish mowers used in 12 to 18" high pasture grass, if it is heavy, are not the right tool. The slightest amount of grease on a belt and you'll burn up a belt, etc.
b) suggest mow the 20 acres first with your hog and then use the finish mower when the grass is much shorter. After that it will look better every time.
c) By the way, a bush hog with sharp blades will do a surprisingly good grass cutting job if the customer expectations are not too glorious.
3) Depends a lot on what the customer wants ! If the customer is expecting lawn-quality finish mowing you are going to have to mow more often, etc. The fact that they are asking for "finish mowing" may imply higher expectations.
4) Once you have this place cleaned up and cutting becomes routine, I think you can do a good bit more than 4mph.
5) You can certainly mow 20 acres in 8hrs with just about anything 8 feet wide. The question is more what will it look like, will the customer be pleased, and how often do you have to do it ?
6) By the way, I'm a little puzzled: You mention an 8ft bush hog ? 8ft hogs are not common. Also 8' finish mowers are usually gang mowers or multiple units of some sort.
7) What kind of land is this ? Hilly, flat, rocky, heavy growth in an area with lots of rainfall ?

 

[jenkinsph]

Builder,
I was curious what your cut height plans are? If you are trying to get results similar to a finished lawn then it will need cutting more frequently. No way can you cut 18" grass down to 3 or 4 inches without making it look like stubble. So for the initial cut I would use a brushhog then use a finish mower thereafter cutting no more than 1/2 of it height at a time. On my own lawns I try to maintain about 4" mowing height and cut it when it averages 6 to 7 inches. I know you are familiar with all of this but you need to make sure the property owner is on the same page.

 

[JWR]

That is a great mower, but it won't handle my M7040's power output. The 990 is maxed-out at 50HP. I'm 70 engine and 61 PTO.
I'm gonna try either my MX-8 with really sharpened blades or I have access to a 15' finish batwing.

Pardon my nerve to say so, but I think you are under a misconception of sorts. There isn't anything wrong with operating an RM990 mower that needs less horsepower to run than your 7040. It's always good to roughly match the size and hp requirements of the implements to the tractor but not like it's a hard/fast requirement. Just don't floor your 7040 all the time and you aren't putting out 61 PTO hp anyhow. The only "danger" or concern might be that you have the hp to potentially do damage to the 990. If you don't try to overload the mower in very heavy deep grass, etc. and then force the issue with more horsepower, I don't see a problem. Another thing to note is that the RM990 is 7.5ft cut, not 8ft. As someone else mentioned the flail type blades on the 990 make it much more durable in rough cutting. Note also that the gearbox on the 990 is rated at 75hp. so I interpret their "25 to 50" hp range of tractor as a nominal recommendation. Just my opinion. [Now if you were going to turn the machine loose with hired hands that you barely know ... whole different ballgame.] By the way, I like Landpride a bit better than Woods for finish mowers. Landpride makes 8 and 10 ft versions in both medium and heavy duty flavors and with flail type blades... and they will handle far more hp too.

 

[art]

i agree, 18" tall grass is rotary cutter territory

then finish mow it after it's cut down to a reasonable length.

8' mower: 3 to 4 acres an hour

15' mower, 7 to 8 acres an hour

3mph for rotary cutting with a 70hp 8' is awful slow. I cut at 5mph with a 15' mower with 70 hp. 6mph when I had an 8' mower. (it would go faster, but it beat me up too bad going faster). (although, your grass may be thicker than it is here, but even in really thick thick wet grass I only gear down to about 4mph with the 15' rotary cutter and it plows right thru that.

Your about right here with the 15 ft cut. We just took in trade a 15 foot TD-1500 bush hog with fifty horse on it and I'd say you are right for what I've seen with these in my area. I played on five acres and with a lot of trimming I was back in less then an hour.

 

[bilrus61]

I would give the MX8 a try. I mowed out by my mom's flower beds with my MX6 on my Kubota L 5040 and was quite please with the cut. Really couldn't tell the differnce from the Grasshopper ZTR (dull blades) except for a very small windrow that dissapeared after the first little rainshower. The MX 6 leaves it looking like a lawn so try the MX8 a round or two. The grass was about foot tall fescue. I then mowed a rough field with 4 and 5 foot tall weeds and again was pleased with the appearance of the field with the MX 6. As to speed of the cut, much I think would depend on the shape of the field. A long narrow field will cut much faster than a square one with all the turns at each corner.

 

[powerstroke444e]

Builder
At the farm we have a newer John Deere Batwing brush rough cut mower we ussually pull it with a 225hp but you can pull it with alot less. It has 1000pto set up and has a double set of blades on it were a regular brush mower has one set. It is suppose to be for chopping stalks at about 7-9mph. But have found it leaves the waterways like a lawn even if we only hit them once in late summer. We use to have a 15 foot flail mower but to didnt do as good as this new mower.

Point being look for a good batwing with a double set of blades or see if the mower you have can add this options. I will try to get photo next time we have it out which will be awhile as got a 6 inch rain last night and some areas got over 10 inches