Blade Tip Speeds...educate me!

[LD1]

One thing I have noitced is that most of the true HD cutters out there run a lower blade speed. Like 11k-13k or so.

The medium and lighter duty cutters are the ones that go 16k+

It dont take super high speed for cutting brush, saplings, and briars. Cutting pasture grass is where a higher tip speed shines.The HD units are geared more toward brush clearing and the meduim duty is geared more toward pasture maintenance

 

[SPYDERLK]

One thing I have noitced is that most of the true HD cutters out there run a lower blade speed. Like 11k-13k or so.

The medium and lighter duty cutters are the ones that go 16k+

It dont take super high speed for cutting brush, saplings, and briars. Cutting pasture grass is where a higher tip speed shines.The HD units are geared more toward brush clearing and the meduim duty is geared more toward pasture maintenance

I agree. Something I find odd tho is that I cant tell a cut difference running my ~ 12K bushog at 540 or 750. ... Thick grass, switch from one to the other. Next time around you cant even find where you did it.

So I just run 540.
larry

 

[Tejas]

<my 72" Bradco I customized.

Thanks folks for the info. I have been able to work out some calculations. This for the neighbors 60" brush cutter...for his Bobcat 663 with 15gpm. In light of these calculations, I am going research direct drive units a bit and compare costs.

Motor Torque in-lbs. RPM @ 15GPM Gear box Ratio/RPM Cutter Circumference Blade Tip Speed (feet per minute)
1:1.46 1:1.93 56 x 3.14 1:1.46 1:1.93
6.15 CU 2936 563 822 1087 14.65 12,042 15,925
7.63 CU 3643 454 663 876 9,713 12,833
9.59 CU 4579 361 527 697 7,721 10,211

These cutters will only do a little "grass" cutting/mowing. Most of their lives will be spent mulching Cedar and huisache trees. I have read the arguments about the slower BTS for cutting thicker brush, for some time now, and don't agree...not real sure if "brush" and "trees" fit in the same category, but I think they do. I can tell you the performance of my 2 blade cutter is increased with higher RPM. This is especially true when getting into 4-6" trees.

My 72" is turning a regular style stump jumper with 2 standard shredder blades. Some of you with heavy brush cutter experience may be able to chime in...I believe my next step is to go to a heavy stump jumper/blade carrier. I'd like to have a heavier flywheel to increase/maintain momentum. I am torn between 2,3,4 blade types. I'm leaning towards using the heaviest blades...which leads me to believe 2 blades are the way to go...any thoughts?

 

[Tejas]

^ haha...this forum is tough to post on....sorry for the mass of numbers there, it looked organized when I hit post.
* and the sideways pic

 

[brown40]

The tree shredder I like the looks of is made by Brown. I think it has 4 blades and requires 4x more tractor than I've got to run it! It's be a good reference for an established tree design.

 

[Tejas]

Well, I tried to turn the photo on my computer then attach it...still coming up sideways. Sorry, not sure how to fix.