Flip over question

I agree that hooking a chain around an axle or to the top link is an absolute no no. If a chain is hooked to the appropriate drawbar, couldn't there be a condition of enough torque and traction to still flip? This would require that the tires would have to move backwards as the distance between the puller and pullee shortened. I suppose this might be self limiting as the slippage required to move backwards would hopefully let the wheels spin?

Clearly a pulling tractor can raise the front wheels so the drawbar pull isn't putting only downforce on the front wheels.

I'm not into following tractor pulls. Has a pulling tractor ever back flipped with an appropriate drawbar connection?

On the matter of Elm trees in Eastern Canada, Dutch Elm did not hit there until the late 70s. 250 years ago when our forfathers cleared that land they left Elm trees for pasture shade. Some of these trees grew to be massive. I had one that my entire 40 cow holstein herd could take shade under. The shade pattern was 80 feet diameter any direction, when sun was directly over head. Some of these trees had as many as 6 - 18" stems comming out of one stump. As we started more confined feeding and less pasture, we soon realized how much of our fertilizer these trees were sucking up. The root system will spread further than the limb spread. The Elms in center of fields had to go, as they also caused a lot of damage to tillage equipment. Dutch Elm in 1978 was also closing in on us. Forestry specialists suggested if we get rid of old trees we may save the young trees.

My dad had removed 21 of these trees in 1960. Cut them all with a chain saw, drilled holes in stumps and filled with salt. I wanted to cut more at that time. My dad said, " I waited until your grandfather was gone to do this much, you can wait until I'm gone for the rest" In 1960 there were a few D6 and TD14 in our area. None of them would tackle Elm trees or stumps. I said before the D7G was not well equiped for what I was doing 16' angle tilt blade. Owner had stored it at my farm over winter, and the root rake was 50 miles away and nothing there to load it. I told my dad I was going to remove 3 Elms before spring planting and owner came for his D7. My dad said the D7 wouldn't do the job and laughed. The big tree did take 4 hours and that included rolling off the field. Two smaller trees both Elm each took about one hour. For the cost I went back to the chain saw, drilling holes and salt. Little did we know how easy Dutch Elm would make this job. Yes the Elms down there are all gone too.

It was truly the trees that got used for livestock shade that became massive. Besides the 80' branch spread many of them were over 100' tall. Of course you know what cows would do under trees. The Elms sure loved the diet. Most of our Elms that grew in forest didn't do near that well. In fact as I think about it, the Elm didn't not really compete well in size against other trees in our area. They could however suck the fertility away from alfalfa, corn, timothy, potatoes, etc. I do know the smaller Elms from forest stands made better lumber. They had finer growth rings, and of course slower growth.

A forester estimated it weighed close to 25 ton.

By the way you need not worry about being called an idiot. Your own advertizing does well.

What odds would you give me if I listened to your advice that "after 1940 all the major makes had safe drawbar design to make rearing up impossible unless something stupid was done to leverage the tractor to make it rear up". Would you drive the tractor beliveing that? If you believe that, you aren't gonna be able to get to the clutch and throttle in that 1/2 to 3/4 of a second needed. I wouldn't be able to collect on the bet, but you sure would pay dearly.

Sorry, I'm not trying to insult you. I'm just suggesting that when we say things like that we tell the whole story.

OTOH I believe the statement "the hitch is designed such that, if the load is properly attached the tractor will not flip." is TOTALLY wrong especially when it leaves out the words "and the tractor is configured as designed." Any addition of extra ordinary weights and or power changes the whole equation. Even stock weights and power a combination of torque and traction can overcome the load resistance, and you have less than 3/4 of a second to recognize and respond or you're dead in the next 3/4 second. Kinda like snapping a load binder over center.

I have located some good information and attempting to contact a recognized tractor safety expert and will post more later.

As to your 3 point scenario above, the top link is supposed to limit the travel of the tractor flipping. So if the top link fails or you use a chain instead, you're screwed.

In my day I have hooked as many as 4 tractors together. Always put the lighter tractor in front, and always hook from the front of one to the rear of the next, no running chains or cables under the tractor, for towing.

I think it's fantastic that people on this board are willing to share their experience and wisdom regarding not only safety, but virtually any issue.

It's excellent to provide the examples of "this is a safe way to git'er done" and "this is a dumba$$ way to do that" and the wonderful thing is the broad list of examples this group can come up with.

Wouldn't you agree that there is some added value in exploring the mechanics of what will cause a tractor to back flip? Armed with both the examples AND the theory (why it's going to flip) then intelligent people can recognize the root cause of the accident in a situation that may fall outside of the examples that have been presented.

A casual reader of this thread (and others even in the puller forum) could come away with "it flipped because they used a small tractor to pull a big stump" and proceed to pull a stuck car out of the mud attached to the top link or the 3 point drawbar with a chain top link. (just happened again) The next casual reader might read "it is impossible to flip a tractor pulling from the original drawbar because it has been engineered to only raise the front end so far and then stop."
and be woefully unprepared with clutch and throttle the next time they attempt a difficult pull.

Yes, the "expert" I referenced is a college professor who collects a lot of case studies and statistics, etc. , but he also is a recognized expert on the mechanics or dynamics of what conditions actually cause a tractor to flip, and I think that might be worth hearing about.

I once spent 4 hours with a D7G removing an Elm tree. By the time I had a lean on the tree, I also had a trench 8' deep all the way around it. I admit I didn't have the proper blade for the job.

Getting back to pulling what may be insurmountable objects with a tractor, it has always been a common sence activity. If you think for one minute the object is more than the tractor will pull, the safest thing to do is hook another tractor on front end of first tractor. Always put the smaller tractor on front. If the smaller tractor does nothing more than keep front end of the larger tractor down, it may make the pull successful. It will make it safe. On the matter of breakage, it has always been the responcibility of user to examine his or her tools.

I was really trying to get to the mechanics/physics of a flip over. Key question is - if a correct drawbar hitch creates downforce on the front wheels then how come we can raise the front wheels pulling? And does that reach equilibrium or are we just approaching a local maxima, the other side of which will bring destruction :) (sorry. couldn't resist)

I'm now pretty much convinced that it's a function of the lockdown of the tire contact point and the torque supplied about the axle (somewhere between locked down and lots of flipping torque).

I did a reasonable web search last night and every flip over accident I found specifically mentioned an unsafe attachment of the chain, usually to the top link. I could not find one single reference to a flip over during a tractor pull, but I'm not certain it has never happened. Maybe I'll ask over on the puller forum, although I expect some of those folks are here too.

Interesting problem though. Wish I were 40 years younger and in a mechanical engineering program! I think I could pull Allan's D-8 over but it would take a heckuva winch and cable!

Thanks to everyone who contributed. As always there's wisdom in each reply.

I think this horse is dead!

Been a whole lot of people hurt or killed by tractors going over, and as far as I'm concerned, impossible doesn't exist. Never under estimate the power of a tractor under the right conditions.

Mark

A tractor was made to pull a brush hog or a plow or a harrow ect.
A track hoe is the tool for stumps.
And a dozer is the tool for standing trees.

So if you're going to pull big stumps, get a big CAT!

Thurlow, I'm smiling, not taking a dig.

Allan, when are you sending the D-8 so's I can clean up these 5" poplar sprouts?

Thanks to all.

In a backward tip, a tractor can flip completely over in 1 1/2 seconds, but the point of no return can be reached in 3/4 of a second.

From an article by Dennis Murphy, Associate Prof. Ag. Engr. Department of Agricultural Engineering, Penn State . He seems to show up a lot in a search.

The puller tractor also raises the front end because the rearward torque about the axle exceeds the forward torque due to front weight and the drawbar pull leveraged through the location of the drawbar.

Given enough horsepower and traction I believe the tractor could flip. I just don't know if it ever has actually happened under real world conditions. You'd have to lock the wheels down "instantaneously" and have enough horsepower to accelerate the mass of the tractor around the axle up to an rpm sufficient to maintain the required torque. Or sumptin' like that.

I (or my son) am pulling stumps with my H, or maybe I've borrowed that 1486, and we are hooking up chains correctly, is the risk of flipping zero? or just very low?

I seen posts in hear about chaining posts to the rear wheel and just rotating the tractor over backwards. I agree that is an inappropriate attachment.

So long as this drawbar is stiff (not 3point) ans does not break, the tractor can not flip over backwards.

Now, the tractor car rear up a whole lot, & scary things can happen. But it can't really flip over backwards. The drawbar, even tho it is short, prevents this.

At some point there is a balance.

Plowing with a 2pt plow I've had the front end rear up quite a bit. This is a tractor with fluid in the front tires. Add in the furrow, loss of steering, the 'wow' factor, and the plow digging in deeper, and real bad things could happen. But, it likely never would flip over. Likely. Got pretty high on my once tho, lucky I got the clutch & brakes in, let the front back down slow.....

If something breaks, anything can happen, all bets are off.

--->Paul

I'm not trying to be a smart a$$, but the only way I'd tie into a tree or a stump is with a D8 Cat equipped with a blade and a ripper.

I just don't think hookin' a wheeled tractor to an inmovable object is a very good idea at all.

Remember, there is as much tree under the ground as there was above. That's a lot of anchor.

Allan

I've watched your posts here and I do respect your opinion. I AM talking little stumps here, but it's relative. I'm not so much focusing on whether the stump gets pulled as to what are the circumstances that "could" cause a back flip. If it's an immovable object relative to what you're pulling it with, the question is whether following all the rules removes the risk completely or is there still the edge of the envelope somewhere that could bite.

I don't believe the drawbar setup insures the safety. Your having the wheel in the air for 100 yards proves that the drawbar downforce is commonly overpowered by torque. One article I saw points out that the resulting vectors of the drawbar etc actually result in the tire contact patch becoming the pivot point which is always going to be below the pulling force. I think loss of traction and power typically cause equilibrium and save us. I also believe that if something suddenly locked up the wheel slippage the tourque could overcome the drawbar and backflip a tractor. There was a post on one of these forums in the last few days about pulling a blade and catching it on some equipment in the weeds.

I did grow up around farm machinery. I haven't spent the time on tractors you have, but I have been blessed to experiece the front wheels off the ground plowing with a big red diesel cab tractor.

And Allan ol' buddy, I have had a D2 trying to rear up while pulling brush and old concrete foundations. The D2 also quickly digs itself a ramp to make it even more exhilarating.

I'm definitely NOT a Ralph Nader type (finalist for biggest a..hole on the planet), but I want ALL the information I can get about the situation so I can make my own decision.

I think it's even more important to raise some of these issues with us novices, so we don't go from fat, dumb, and happy to dead when the top link breaks on the three point which is "impossible" to flip or we emulate Allan with his flexible top link (just kidding Allan).

And oh yeah, one of my best friends was killed 40 some years ago when he caught one of those boundary conditions and ended up with a tractor on top of him.

Sorry for the long post.

Since we're just playin' gamesmanship here, take your crawler a "push" the tree over with the blade first, then rip the ground with the teeth to pull out all those roots.

But, if you are just working with saplings anyway, heck, gasoline and a match? :>)

Allan

Besides the D-2 has no hydraulic or blade. My dad bought it in '41 to pull 4-16's! I guess you'd call that a half a plow though :)

PS, Dad used dynamite on stumps!