Preventing tractor back flip

[SPYDERLK]

An elastic connection does not add another "vector." What it does do is reduce the energy going into the tip-up during the stretch, stores that energy, and add that energy back into the tip-up during the rebound. To be perfectly accurate it probably converts and wastes a bit of the energy as heat.

So when it adds tip-up energy back to the tractor during the rebound, that may make enough difference to flip the tractor. But if that is so, a bit more power from the engine could do the same thing without the elastic hookup.

So anybody who says a tractor cannot flip with an inelastic chain, but could with an elastic cable, is admitting that a tractor with enough power to lift itself, against the decreasing leverage of the load as the drawbar lowers, can flip with an inelastic chain.

In a situation where there is ample power and traction to pull a load, but then the load stops dead the tractor tends to nose down under deceleration and then back upward under power after it stops decelerating. Stored energy will give it an extra kick to speed the backtip ... perhaps enuf to take it over.
larry

 

[Egon]

And remember that although it may be counterintuitive, if the nose comes up even an inch, the axle and tires have already moved rearward towards the load. So no matter how counterintuitive it may be, that is what is happening./QUOTE]

Nothing counterintuitive about it but lets say the distance between the tire and the load will become shorter. The tire, the load or both can be involved in the movement.:thumbsup::thumbsup:

 

[IronHog]

So you're saying there's a chance.


(Dumb & Dumber reference there)

Oh yea.

I think you could ride a powerful tractor over easy logging off the 3 pt hitch.


But you'd hafta keep the RPM's up and either be a careless or bad operator.



I'm much more concerned about the tractor rolling on me while hooking up tongs, a stick coming into the rack, or getting a hand crushed/cut while logging. Flipping backwards is a more theoretical than actual risk in my particular situation.

I need to take some pics next time we bank a load or two. True logging with a tractor is pretty much a dying art around most parts.

 

[Short Game]

True logging with a tractor is pretty much a dying art around most parts.

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.

 

[Farmwithjunk]

The ol' Magical Cause Syndrome. Leads to better understanding of everything that is not obvious.

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.

 

[xtn]

The vector I was speaking of was the tractor end of the cable moving back toward the load. I have loaned some chains and had them come back to me stretched (a.k.a., ruined). Not much rebound in them. The cable gives the tractor a way to multiply the tipping force over the time it is storing its power in the cable. This could be a huge factor and the difference between flipping and not flipping.

When I lived on the beach and had my little '51 flathead four Jeep, I could pull just about anything out of the high sand, trucks, Caddies, you name it. I had 100 feet of 3/4" polypropylene line. My little Jeep would take a low gear run and use its power to store force in the stretched line. About the time I could pull no farther, I'd lock the brakes and the stretched line would snap the Caddy out of the soft sand.

That is not "another" vector. That's the same vector we've been working with the whole time. And I know what you mean but you're saying it wrong; the cable adds energy to the tip during the time it is rebounding, not while it is stretching.

What you did with your jeep is commonly referred to as snatching. If you think about the dynamics you will recognize that the energy is stored during the stretch, and added back in during the rebound.

 

[xtn]

In a situation where there is ample power and traction to pull a load, but then the load stops dead the tractor tends to nose down under deceleration and then back upward under power after it stops decelerating. Stored energy will give it an extra kick to speed the backtip ... perhaps enuf to take it over.
larry

Basically, yes. According to LD1 this could never happen, as it will obviously bring the nose up AND pull the tractor backwards towards the load. He thinks that combination of movements is not possible.

 

[tmajor]

What you did with your jeep is commonly referred to as snatching. If you think about the dynamics you will recognize that the energy is stored during the stretch, and added back in during the rebound.

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.

 

[xtn]

The tire, the load, or both can be involved in the movement.

Sure, except when we're dealing with an immovable load....

 

[xtn]

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.

Sure. Nothing in our world is completely inelastic.