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Matt's Off Road Recovery.

bigun said:
Did you notice that they ran pins through it to keep it from bulging again?
Besides if you don't try something how do you know if it is going to work or not?
R.A.H. Said listen to the experts tell it won't work then go out and do it
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I'm sure it will work fine...... Right up until it doesn't.




:flipoff2:
 
Muckin_Slusher said:
Nope. That WAS an absolute shit fix.

If all that spindle got was a slight chamfer and one pass with the mig like the video showed, it's gonna fuckin fall off.

That spindle doesn't see any "rotational" torque. All it sees is a shit-fuck ton of tension from the drive cog and delivered through the track. Consider a situation when the track has traction and that machine is trying to pull something heavy while driving forward. If the drive sprocket can deliver 1000 lbs of tension on the track, then that spindle is seeing 2000 lbs of force.

I've no idea if force from the sprocket is more than what that spindle sees when going over a bump or hill or backing into something, but I would guess the latter is greater. Argo's always bust their rear spindles, I would guess they see the greatest abuse.
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Good explanation; thanks!
 
bigun said:
Did you notice that they ran pins through it to keep it from bulging again?
Besides if you don't try something how do you know if it is going to work or not?
R.A.H. Said listen to the experts tell it won't work then go out and do it
Click to expand...
I dug up some square pressure vessel specs from a nuclear power plant build in JNHEscher bus thread on the old board I think?

The takeaway was that pressure vessels aren't supposed to be square:stirthepot:
3/4" thick 316 stainless plate to hold 37 PSI.


1646141481274.png
 
Full disclosure I watched the referenced video and you guys are right about the brackets and mounting to the pads lack of "finish" etc. but I will allow them the opportunity to finish the build before calling them ****s.

I can see the happiness of using simple square cut tabs to get the system done versus hours of cardboard cad, trial and error etc.
The finished look sucks but maybe they can salvage it.

The head scratcher was mounting the lower link mounts on the bottom of the belly, WTF.
Very confusing there, that has got to be a giant hang nail. Maybe they will create some transition to it.

Lots of wait and see, but for something that had to be pre-drawn I'm not sure why they made those choices.
 
we do lots of air testing and bs for natural gas and one thing you never find is a flat plate welded to the end of pipe to test against, always a rounded end cap. i ve never done the math to support the fact the flat plate will bow out so thank you. thats awesome. :beer:
 
I'm sure many of us have use 3/16" bumpers as air tanks with no issues up to 120PSI, I know I did on my XJ. Do agree it sounds like a shit-ton of effort versus just shoving a tank underneath, or even just using the bumper.
 
The square cut link tabs are just not aesthetically pleasing to me, but maybe they like them.
Hell, there are people here to think square tube links look cool.
 
I haven't read the past few pages, so I might be way out of context here, but when it comes to air tanking things, the rear bumper on my CJ5 is 2x6 3/16" wall box tubing with beveled ends I welded on and it holds 150 psi easily. I've had to weld a couple leaks over the years from particularly hard hits, but they were pissing leaks, not any sort of pressure vessel rupture. I have a friend with sliders on an XJ built into tanks the same way, and another friend who has air tanked his roll cage.
 
budget76 said:
I'm sure many of us have use 3/16" bumpers as air tanks with no issues up to 120PSI, I know I did on my XJ. Do agree it sounds like a shit-ton of effort versus just shoving a tank underneath, or even just using the bumper.
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djljeep said:
I haven't read the past few pages, so I might be way out of context here, but when it comes to air tanking things, the rear bumper on my CJ5 is 2x6 3/16" wall box tubing with beveled ends I welded on and it holds 150 psi easily. I've had to weld a couple leaks over the years from particularly hard hits, but they were pissing leaks, not any sort of pressure vessel rupture. I have a friend with sliders on an XJ built into tanks the same way, and another friend who has air tanked his roll cage.
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There's gotta be a huge difference between a 4-5 foot wide bumper hanging off the end of a chassis and 20 foot long frame rails twisting and flexing to support a heavy off-road vehicle.

Neither situation is going to fail catastrophically as in grenade. Both could leak (easily addressed on a bumper) and blow out, much like any air tank can when it rusts inside along the bottom. NBD.

However, what I would be worried about is fatigue from pressure cycling. Commercial airliners are designed to deal with pressurization swings and IIRC have a related service life. If your bumper fatigues and fails it is NBD. I would not want to subject an expensive (materials and labor) frame to weaken.
 
budget76 said:
I'm sure many of us have use 3/16" bumpers as air tanks with no issues up to 120PSI, I know I did on my XJ. Do agree it sounds like a shit-ton of effort versus just shoving a tank underneath, or even just using the bumper.
Click to expand...

djljeep said:
I haven't read the past few pages, so I might be way out of context here, but when it comes to air tanking things, the rear bumper on my CJ5 is 2x6 3/16" wall box tubing with beveled ends I welded on and it holds 150 psi easily. I've had to weld a couple leaks over the years from particularly hard hits, but they were pissing leaks, not any sort of pressure vessel rupture. I have a friend with sliders on an XJ built into tanks the same way, and another friend who has air tanked his roll cage.
Click to expand...

The "Tech" here is a thing called hoop stress. As the surface area gets bigger the strength required multiplies at a different rate, it is not linear as far as I know.
Hydraulic cylinders are easy thing to visualize for most of us. A 10,000 psi porta-power cylinder with a 2" bore has a wall thickness of 1/2" which equals a hoop stress of 20,000 PSI.
But a 5" bore cylinder (more tons of force) needs a 1.25" wall thickness to keep the same 20,000 PSI of hoop stress.

This tall section of the frame rails are this press problem. The force is trying to make the rectangle tank round, enough force it was visual.
I would think your bumpers and sliders don't see this stress do to their smaller sizes.
 
^^^good points on the wall heights etc. been a long time since I've taken the engr courses for pressure vessels and such
 
LOL, someone posted rectangular pressure info on MORR channel. It's been deleted.
 
budget76 said:
I'm sure many of us have use 3/16" bumpers as air tanks with no issues up to 120PSI, I know I did on my XJ. Do agree it sounds like a shit-ton of effort versus just shoving a tank underneath, or even just using the bumper.
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I did one side of my last buggy frame rail. It was 2”x3”x1/4” wall and ran from the back of the transfer cases with a degree angle up to around the side of the engine to level out to the front bumper. 120 psi in it no issues. I had no room in it for a roundy round tank.

Edit: I also ran an air line from one side frame rail to the other side frame rail for more volume see :flipoff2:
 
Landslide said:
I did one side of my last buggy frame rail. It was 2”x3”x1/4” wall and ran from the back of the transfer cases with a degree angle up to around the side of the engine to level out to the front bumper. 120 psi in it no issues. I had no room in it for a roundy round tank.

Edit: I also ran an air line from one side frame rail to the other side frame rail for more volume see :flipoff2:
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I think a 3" span is totally different than 10" or whatever Matt's frame height is...and that's why everyone here has no problem with pressurizing their bumpers.
 
Landslide said:
I did one side of my last buggy frame rail. It was 2”x3”x1/4” wall and ran from the back of the transfer cases with a degree angle up to around the side of the engine to level out to the front bumper. 120 psi in it no issues. I had no room in it for a roundy round tank.

Edit: I also ran an air line from one side frame rail to the other side frame rail for more volume see :flipoff2:
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As I recall they had 7" channel for their frame rails and the plate that they used was only 3/16" so it was doomed from the start.

Aaron Z
 
plym49.2 said:
Holy crap. An intro shot by Michael J Fox, and a yawner of a video.
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I thought how Matt ended up being Matt's off road towing was kind of interesting my self, I guess since John Waynes son was involved they should have been shooting at the bad guys:flipoff2:
 
bigun said:
I thought how Matt ended up being Matt's off road towing was kind of interesting my self, I guess since John Waynes son was involved they should have been shooting at the bad guys:flipoff2:
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I must have skipped that part. Could not do 40 minutes of 'gee, my dad was famous'.
 
Not the outcome he wanted I'm sure, but not a bad deal compared to fighting a long drawn out court battle. 15K really ain't that bad a price to get something like this off your mind!
 
plym49.2 said:
'No contest' is not a guilty plea, and is not surprising since everyone wins. But his mouthpiece should have been able to get rid of the probation requirement.

Next time, Matt needs a Jewish NY lawyer. Captain America couldn't beat them.
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LOL A buddy of mine used to warn he had two, a young one who was hungry, and an old guy who knew the law
 
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