Flail Mower Let's talk flail mowers

[IslandTractor]

You can't have a significant pressure gradient without a seal...and there is no seal. Only the sides of the mower touch the ground with actual contact. The roller touches, but has gaps above it, and on the ends. The front is open...chains, metal bars and rubber shrouds don't create a seal and often aren't in contact with the ground. Until somebody shows an actual reference, I'm sticking to reality...the closer to the ground the grass/brush makes contact with the mower, the less it will move around, and the better the cut will be. I don't know why anybody would even worry about the theory...if the ground is full of rocks, and you don't want to trash your blades, lifting the flail high enough to clear them will still let you cut that brush. Will it be perfect? No. Will it get cut down? Yes. That's all the guy asked....will the mower worked raised up a bit. Yes, it will still work.

There is a pressure gradient between the front and rear of any fan and most have no seal. Wind or air movement is all about pressure gradients and doesn't require seals per se.

Rotary mowers create pressure gradients that allow clippings to be forced into a shoot and collected. A flail does generate a "pressure gradient" to create a vortex that causes cuttings to be recut or mulched. Trapping the cuttings under the mower allows them to be recut more efficiently just as with a rotary cutter with the grass shoot blocked. With the flail mower elevated, there is enough escape of air and cuttings to diminish the recutting which lowers the quality of the cut. It will still cut but it will not recut as efficiently.

 

[GManBart]

There is a pressure gradient between the front and rear of any fan and most have no seal. Wind or air movement is all about pressure gradients and doesn't require seals per se.

Rotary mowers create pressure gradients that allow clippings to be forced into a shoot and collected. A flail does generate a "pressure gradient" to create a vortex that causes cuttings to be recut or mulched. Trapping the cuttings under the mower allows them to be recut more efficiently just as with a rotary cutter with the grass shoot blocked. With the flail mower elevated, there is enough escape of air and cuttings to diminish the recutting which lowers the quality of the cut. It will still cut but it will not recut as efficiently.

That would be true if you were talking a traditional fan with blades shaped like aerofoils intended to create low pressure on one side, and high pressure on the other. That simply isn't how a flail works because the blades are parallel with the direction of movement, not nearly perpendicular to it like a desk fan.

A flail will generate some rotational air movement, but narrow, sharp blades that have virtually zero angle of incidence (and angle of attack, but that would be carrying it a bit far) aren't going to create any significant pressure as they pass through the air. That's why horizontal rotary mowers have part of the blade angled offset from the direction of rotation (angle of incidence) to create a pressure differential pulling the grass towards the blades.

Imagine a flail mower mounted to a boat that happens to have a 540 PTO drive. You can set the flail right on the top of the water, and start it turning...some water will go around the rotor, but the boat isn't going to move a whole lot because it simply can't generate a significant amount of pressure.

The quality of the cut, and the quality of the mulching are two entirely different things. Clippings being cut a second time doesn't change the quality of the cut, it changes the quality of the mulching, and what you see left lying around. You have a blade of grass....a blade cuts it, and the standing part doesn't get cut again in most cases....that sets the quality of the cut and how level and even it looks. It's a pretty safe bet the a significant portion of the mulching capability of a flail happens because the clippings wind up on top of the already cut grass, leaving them where the blades can make contact with them again....and watching the big clumps that get left behind says that has to be true. Whether there's enough suction to draw clippings up into the blades is another question, and I'd love to see references on it, but I doubt they exist.

 

[IslandTractor]

Agree that data is needed to understand this issue. "In God we trust, all others must show data".

While flails don't have angled blades, they do still create considerable "wind" simply because they are moving at ?1000-3000 feet per min and even if the blades themselves are relatively aerodynamic, the mounting points, clevises and bolts are not so would generate "wind" which is contained under the mower. Presumably that air flow dissipates more rapidly when the mower is lifted.

 

[Blade Breaker]

Hi,

I am currently using a rotary mower and a side disc mower to mow road ditches and waterways. I get all I can with the rear mower then switch to the disc mower to reach up the ditches in the steep parts. I have been looking for something that would mow behind the tractor like the rotary but also extend out and reach up and down the steep areas so I don't have to keep switching mowers. I found this and it looks like it would work for me. Anyone have any experience with this?


Diamond rear swing flail

Rear Swing Flail Mowers – Diamond Mowers

 

[Blade Breaker]

Hi,

I am currently using a rotary mower and a side disc mower to mow road ditches and waterways. I get all I can with the rear mower then switch to the disc mower to reach up the ditches in the steep parts. I have been looking for something that would mow behind the tractor like the rotary but also extend out and reach up and down the steep areas so I don't have to keep switching mowers. I found this and it looks like it would work for me. Anyone have any experience with this?


Diamond rear swing flail

Rear Swing Flail Mowers – Diamond Mowers

 

[hunt4570]

Hi,

I am currently using a rotary mower and a side disc mower to mow road ditches and waterways. I get all I can with the rear mower then switch to the disc mower to reach up the ditches in the steep parts. I have been looking for something that would mow behind the tractor like the rotary but also extend out and reach up and down the steep areas so I don't have to keep switching mowers. I found this and it looks like it would work for me. Anyone have any experience with this?


Diamond rear swing flail

Rear Swing Flail Mowers – Diamond Mowers

Looks like the answer to a lot of questions.. cheap too I bet!

 

[leonz]

Please contact your local diamond implement dealer for a customer list as that is the
fastest way to find an owner of this mounted implement.

The Diamond folks have been building mowers for a long time.
You will have to decide if you want an integral mounted flail mower
or a boom mounted mower first.

Saying that the majority of these units are owned by municipalities to
mow ditch banks on roadways the flat areas the mules can access safely.

Many users have loaded tires and or wheel weights on the outboard(roadside)
portion of the tractor to maintain its stability when mowing so keep that in mind.




You will find that a boom mounted flail mower with hydraulic drive will
cost you more money about the same money, but you will have to compare
the price between the two types of flail mowers before you can make a decision.

This type of flail mower depends on the tractors hydraulic system to operate the
mower mounting frame side shifting cylinder and the tilt cylinder frame to position
the flail mower for work while the Rear Power take Off operates the mower through
the drive shaft to the right angle gearbox and then to belt final drive for the flail mower.

I believe the parent company is located in England.


I want you to succeed not fail.

 

[leonz]

Agree that data is needed to understand this issue. "In God we trust, all others must show data".

While flails don't have angled blades, they do still create considerable "wind" simply because they are moving at ?1000-3000 feet per min and even if the blades themselves are relatively aerodynamic, the mounting points, clevises and bolts are not so would generate "wind" which is contained under the mower. Presumably that air flow dissipates more rapidly when the mower is lifted.

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I cannot attach pair of crude hand made drawings illustrating the differences in knive hangers as they are too big using picasa GRRRR!!!!!!
I will gladly send the files to anyone who would like the drawings to show the difference in knife mounts.
The Mathews lawn genie knife hangers allow a slotted mount knife to become airborne as they provide the knife the range of motion to move sideways and become an airfoil due to the tapered knife edge.
The 45 degree angle of the stamped and rolled knife aids in its aerodynamic lift at the high speed of rotation required for mowing

Sadly these knife types are no longer being stamped(I am working on that and an additional aid for flail mower owners
with the current mounting station types.

 

[Halftrack]

Blade Breaker, you might also check Betstco and their AGL line of flail mowers. They advertise on ebay and are listed under flail if want to look at their models. Perhaps they have been discussed in this thread at some point or someone could comment on their quality, I can't. The AGL models are pto driven and require two circuits to adjust the shift and bank angles. Might be what you are looking for.

 

[esbwn]

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hello esbwn,

If I have not done it already I want to welcome you as the newest member
of the "Flail Mower Nations"(no passport required).

No, you are not wrong esbwn. The correct term is "pressure gradient".

If the mower shroud is not close to the ground the ground underneath the
flail mower does not create the restriction required to create the pressure
gradient needed in front of the flail mower rotor to create the lift needed
to carry the clippings up and over the flail mower rotor and back to the ground.


Always think of it this way; if your upright vacuum cleaner with the carpet beater brushes
is held above the carpet while trying to clean it the vacuum cleaner will be sucking only
air and very little dirt except for the occasional dust bunny that wants to sacrifice its self.

Thanks leonz! You have already welcomed me but ill take the welcome again! Thanks for pointing me toward Flail Master for blades, pins, ect. Kristi was really easy to work with and even helped me buy a few extra knives instead of paying for shipping! *Shipping was free over a certain dollar amount so why not get a few more blades?*
After my son and I replaced 152 blades it cuts like a dream! Super glad to have one. I will need to replace a bearing at some point in the future, I dont know which one is starting to squeak but every once in a while I hear it. If anyone has replace bearings and put up a step by step instruction and would point me toward it I would be very grateful! It never ceases to amaze me the amount of knowledge on this forum!