Grappling fun - A Picture Thread....

[IslandTractor]

I have to disagree. A 6ft 1/2" ID hose connected to 2ft of 1/4" will have a higher flow rate than 8ft of 1/4" hose (assuming the same head pressure). At least that's what the laminar flow physics says.

How does your theory fit with the fact that flow restrictors are typically only the thickness of a washer? I'm not a physicist but it seems pretty clear that the vast majority of the difference will be because there is even one inch of 1/4" tube.

 

[kminnick]

I have to disagree. A 6ft 1/2" ID hose connected to 2ft of 1/4" will have a higher flow rate than 8ft of 1/4" hose (assuming the same head pressure). At least that's what the laminar flow physics says.

Slightly. But the real drag is in the 1/4" lines and the smaller fittings. If he was going more than 12' total, then yes, you could measure the loss. In this case, the 1/4" line is a restrictor and there would be a pressure drop because of it (the velocity of the fluid would also change).

http://www.lifcohydraulics.com/catalog/pdf/Hedland-(Flow-vs.-Pressure-Drop)-In-line-Flow-Meters.pdf

 

[Luke'sScreenName]

How does your theory fit with the fact that flow restrictors are typically only the thickness of a washer? I'm not a physicist but it seems pretty clear that the vast majority of the difference will be because there is even one inch of 1/4" tube.

I think if you go back and re-read you'll see that this is missing to point slightly.
My comment was also missing the point to some extent because diameter has a much greater effect on pressure drop than length (but length does nevertheless matter). What this means is that even very short reductions in diameter can cause a large pressure drop (as in your washer example). However, I would still prefer to have a 1/2" line cnvert to 1/4" at the end rather than it be 1/4" for the entire distance.

But back to the pictures! Giant grabber arms for the kid in all of us are awesome.

 

[Xfaxman]

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But back to the pictures! Giant grabber arms for the kid in all of us are awesome.

Here ya go. :thumbsup:

 

[Luke'sScreenName]

You're giant grabber arm is bigger than my giant grabber arm... Just don't tell my 3yr old!

 

[Gordon Gould]

I think if you go back and re-read you'll see that this is missing to point slightly.
My comment was also missing the point to some extent because diameter has a much greater effect on pressure drop than length (but length does nevertheless matter). What this means is that even very short reductions in diameter can cause a large pressure drop (as in your washer example). However, I would still prefer to have a 1/2" line cnvert to 1/4" at the end rather than it be 1/4" for the entire distance.

But back to the pictures! Giant grabber arms for the kid in all of us are awesome.

I am a little confused by this. I can see that you get pressure drop from any restriction while there is hydraulic fluid flow but doesn't the pressure drop or loss become zero or negligible as the cylinder slows at the end of its travel because there is no longer any flow. So there is no reduction in force holding or grabbing the load due to restrictions. Is this correct ????

 

[k0ua]

I am a little confused by this. I can see that you get pressure drop from any restriction while there is hydraulic fluid flow but doesn't the pressure drop or loss become zero or negligible as the cylinder slows at the end of its travel because there is no longer any flow. So there is no reduction in force holding or grabbing the load due to restrictions. Is this correct ????

I think so. Here try this experiment. On you garden hose turn the water flow down to just a drip by nearly closing the water valve. Now lest say the water pressure on your system is 60 lbs. Now just a drip ever few seconds is coming from the hose. Put your thumb over the end of the hose, wait several seconds and you will start to feel the pressure building under your thumb. After some time the full 60 lbs per square inch will build up under your thumb. The flow rate of the flow is very very low, just a drip, but it will still develop the full 60 lbs per square inch under your thumb, it just takes a long time to do it. If a small amount of water leaks past your thumb, it will take some time to develop the 60 lbs again, but it will happen.

So the "flow restrictor" of the water valve nearly shut slowed the flow rate down to nearly nothing, but it still delivers 60 lbs per square inch of pressure over a long time period, at nearly zero flow rate.

 

[Xfaxman]

I am a little confused by this. I can see that you get pressure drop from any restriction while there is hydraulic fluid flow but doesn't the pressure drop or loss become zero or negligible as the cylinder slows at the end of its travel because there is no longer any flow. So there is no reduction in force holding or grabbing the load due to restrictions. Is this correct ????

That is correct, but I am also confused by the term "pressure drop". From my experience, in an open center system, pressure increases with resistance to flow. Instead of "pressure drop", it is "flow rate decrease"

When the grapple lid stops moving, pressure will increase until the relief valve opens. That is maximum clamping force.

 

[Poopdeck Pappy]

Landpride makes a grapple specifically designed for the BX. No SSQA needed, and it only weighs 24lbs more than the BX bucket.

SGC05 Series Claw Grapples | Land Pride

Well, dang it. One more implement to add to the "want" list.

 

[Jim Timber]

Well, dang it. One more implement to add to the "want" list.

It'll ruin you. You won't want to move any wood without it ever again.

I'm completely happy being ruined.