Preventing tractor back flip

[tmajor]

One of the most recent towing experiences with my NAA, involved a huge chunk of concrete barn wall.

I had the chain "under" the concrete, so as to keep the leading edge up, out of the dirt and to add weight on the tires. Hooked to the draw bar, all I could do was spin. I put the 3pt draw bar on, raised it slightly, which gave me the traction needed to move it, however the front was starting to come off the ground. Once I got started across the field, I had to raise or lower the 3pt, as the conditions changed. At times, there was a thin line between "enough traction" and "front off the ground". Lowering the 3pt, would immediately drop the front.

 

[SPYDERLK]

I believe, this can happen with "chain", also. I was getting my truck pulled out of a snow bank, when the chain broke. The chain flew back, took out the bug deflector and the windshield. It seems, like it should have just fallen on the ground.

Yes, the effect is common to everything real. Materials stretch elastically as they take load - up to their elastic limit, at which they begin to stretch plastically and energy is lost. Stronger steels stretch further in the elastic mode and therefore can store more energy. The weakest cables use steel as strong as that of the strongest chains.

What you saw bears a little analysis. There are 2 sources of flyback energy; the elestic tether, and stored energy in the vehicles themselves. When you pull very hard on something that starts to come but doesnt, and then release pull you see it jump back a little. This is even more pronounced on vehicles with a suspension. That fall back "jump" adds to tether rebound. You saw both things added together in whatever proportion. Being very supple, chains fly straight and land in a dense lump - a bad combination. A cable tends to break in a progression, releasing some energy before it fully separates, and then snarls up a bit as it travels. That moderates the danger of the larger amt of stored energy.
larry

 

[RoyJackson]

I believe, this can happen with "chain", also. I was getting my truck pulled out of a snow bank, when the chain broke. The chain flew back, took out the bug deflector and the windshield. It seems, like it should have just fallen on the ground.

I've found that running a chain through an old section of firehose (you might be able to get some from your local volunteer fire house) lessens any spring back. Would work for cable too (which is more dangerous if it parts and snaps back...cable can kill you).
Personally, I use a tow strap rather then chain (except for the times I'm skidding a tree trunk). Although they can part too, they're less likely to do serious damage or injury.

 

[Short Game]

Sure. Nothing in our world is completely inelastic.

You never met my dad.

 

[xtn]

A cable tends to break in a progression, releasing some energy before it fully separates, and then snarls up a bit as it travels. That moderates the danger of the larger amt of stored energy.
larry

I think that is subjective, and depends on where you are standing.

 

[RoyJackson]

I think that is subjective, and depends on where you are standing.

I've seen the damage a cable can do (including an old Navy video of a cable slicing a flight deck crewman in two).
Parted cable exposes strands that are very sharp...they also tend to stretch more then chain, hence more stored energy, before a catastrophic failure.
If one does inspect their cables (good idea to do this on occasion), it's harder to determine wear or strands breaking as they may be internal strands.

Chain links tend to stretch or the welds break. It is easier to inspect (also a good thing to do) them for wear and stretching. If one does break under tension...well, at least you won't (probably) be sliced in half.

This isn't armchair engineering, BTW. We used both cable (which is referred to as wire rope) and chain in the Navy quite a bit.

 

[xtn]

I tried so hard to join the Navy. Was all signed up for Nuke school. **** doctors killed my progress the morning of the swear in.

 

[Short Game]

I am probably in a statistically more vulnerable position running my winch than if I were trying out for the tractor back-flipping team. I guess that is why Warn winches control switches come with such a long lead. When that cable is making popping noises and I see the dust coming out of it, it can make me a little nervous.

Submarines, diesel electric, baby!

 

[RoyJackson]

I am probably in a statistically more vulnerable position running my winch than if I were trying out for the tractor back-flipping team. I guess that is why Warn winches control switches come with such a long lead. When that cable is making popping noises and I see the dust coming out of it, it can make me a little nervous.

Yeah, you are. You definitely want to inspect the cable for strands breaking, rust (if it isn't stainless cable), kinks (which really reduce the strength).
I'd also want to stand behind something like a tree (since an ATV is too small) when using a winch.
It's not that many cables part...but if you're the unlucky soul nearby...well, it can be unfortunate.

Submarines, diesel electric, baby!

Jeez, you must be about 90 years old if you served on one of those old smoke pots.

 

[Short Game]

Jeez, you must be about 90 years old if you served on one of those old smoke pots.

More like, "in."

I don't feel a day over 80. And what's this about smoking pot?

Before the nukes were quieted, and before the spy satellites, we had a mission. If I told you what that mission was, I'd have to kill you. Well, maybe if you put the bamboo splinters under my fingernails, I would tell.

 

[RoyJackson]

More like, "in." I don't feel a day over 80. And what's this about smoking pot? Before the nukes were silenced, and before the spy satellites, we had a mission. If I told you what that mission was, I'd have to kill you. Well, maybe if you put the bamboo splinters under my fingernails, I would tell.

Subs still have a mission, but even when I was in (69-77 active duty), there weren't many diesel boats still in active service.

 

[xtn]

Short Game's mission...

Determine if a sub can do a backflip if pulling from below the prop.

 

[Short Game]

The first time I walked down the dock at Ballast Point in '65, there was a crap-load of diesel boats tied up to the two tenders. I hadn't been to Sub School. One day they called everyone in Shop 67 in and asked if anyone wanted to go on the boats? Two of us were ignorant enough to raise our hands. A week later I was headed to Westpac and an education on Murphy's Laws. But at least I wasn't a skimmer anymore.

 

[Short Game]

Short Game's mission...

Determine if a sub can do a backflip if pulling from below the prop.

Good laugh on that one!

 

[SPYDERLK]

Nothing "magical" about it....for MOST of us anyway....and not that difficult to understand provided one's head is not buried in the sand.

Irony ...

 

[IronHog]

Well, for me it must have been a flourishing science today, even if it wuz some poor production. I dragged out two skinny 90 foot alders and bucked them into 12' 6"s, and lifted them on my bucking forks and made them into 15 inch pieces. I prefer the fat trees, but the power company dropped these and a few others with my permission because they threatened their power line. I dragged them uphill by the receiver hitch in the middle of my box blade and I didn't even flip over backwards.

I'm sure many people drag trees around from time to time with their tractors.

I'm talking more like 2 log truck loads per day vs two trees. Think minimum of 5 tons/hour production. During the 60's and 70's many a big logging crew around here would run 4-5 specially modified two wheel drive logging tractors.
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Get a 65 foot pine at about 2500 lbs on your three point and hit a stump with the butt in 4th gear at 2000RPM. The front tires go real high....real fast. But you'd need to keep the throttle pegged to take it on over IMO.

 

[Short Game]

I do maybe up to a bit over 15 cords each year. Nuff loggin' fer me.

Durn pecker poles, anyway. The two trees are all split and in the cart. Not even half a cord.

 

[Farmwithjunk]

Irony ...

More like iron headed.....

......Speaking of those who still think it's impossible to backflip a tractor in "ordinary circumstances"......Because it's NOT impossible at all.....

 

[IronHog]

I do maybe up to a bit over 15 cords each year. Nuff loggin' fer me.

Durn pecker poles, anyway. The two trees are all split and in the cart. Not even half a cord.

Wood heat is the best!

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The tractor we run had the crank broke logging in the 70's when still new, and the lift arms were broke and shortened at one time too................aaaand it has over a full turn of slack in the front steering from hitting stumps......but the industrial front end is tough enough to take hundreds of violent landings from wheelies and hits from running into things.

Don't try this at home folks.

 

[SPYDERLK]

More like iron headed.....

......Speaking of those who still think it's impossible to backflip a tractor in "ordinary circumstances"......Because it's NOT impossible at all.....

Agreed, since you cant even see that nobody has said that.