Preventing tractor back flip

[Short Game]

I still have a 75 Kawasaki H2 triple. I still remember it as being one of the nastiest handling bikes ever made. Yes you could carry the front wheel in any gear just from the torque.

It's on my list of things to restore when I retire. It's a 100% complete bike and I bought many NOS parts for it years ago.

I was riding a 650 BSA Lightning Rocket when those things were around. Some of them didn't get a mile on them before their new owners were dead.

Used to ride my Beezer up to the Mo-Jave from Smogsville. All my wheelies were in first gear. I loved that it had the perfect combination of front wheel lift and rear wheel spin when I was laying up on the tank. A great hole shot for such a heavy bike. Well, sometimes a second gear shift would pick the front wheel an inch.

 

[beppington]

I sometimes do semi professional logging with a tractor. Not what most of the people here call logging but actual harvesting of large saw timber skidded with the tractor. A drag can weigh up to two tons.

The tractor has a standard, but reinforced three point hitch using tongs to drag attached to a logging rig (metal frame that looks like one of those little fast hook up things on small CUTS). The pull is both behind and above the rear axle.

And after riding hundreds of wheelies on a tractor I can tell you it would take a complete fool on an operator to flip one (with any weight forward) backwards.

If you are running right once the front end gets so high you start to lose traction or the tractor starts to stall (giving you time to back off or hit the clutch).......to flip one over you'd need to get in a rather low gear, have plenty of traction (might even need a diff lock), be hooked to a static object, and throttle that thing over in a violent fashion........

So you're saying there's a chance.


(Dumb & Dumber reference there)

 

[beppington]

skspurling,

I'll ask again (see my original question above) since no one opined on the orignial question directly, try this: neighbors tractor stuck in mud, I come along with 20' chain, back up and run the chain thru clevis/draw bar on my tractor. Now do I back up as close as possible to the tractor in the mud and hook up "short" on the chain or do I hook up "long" as far from the stuck tractor as the chain allows? Or should I add my other 20' of chain and really extend the distance to pull out the stuck tractor?

idaho2

I did in Post #62 (http://www.tractorbynet.com/forums/2471466-post62.html)

And, again, with your example above, I don't think it matters.

 

[Short Game]

And, again, with your example above, I don't think it matters.

I don't think it should matter. I'd run the amount of chain that puts the tractor in the best position to do the job, traction or slope.

 

[Mechanos]

Pulling from a high hitch:

Why doesn't the tractor in the attachment flip?

Look at the attachment and the movie. Is the driver that good?

YouTube

Pretty sure that episode was prefaced by the phrase, "Here, hold my beer", or something similar....

 

[k0ua]

Pretty sure that episode was prefaced by the phrase, "Here, hold my beer", or something similar....

One thing for sure he has never bought a clutch or split a tractor.

James K0UA

 

[foreman Etexas]

One thing for sure he has never bought a clutch or split a tractor.

James K0UA

He looks to be "A few fries short of a happy meal" and probaly on someone elses tractor.............

 

[skspurling]

I did not try to make my brain digest all of what I have read thus far, BUT the concept that has taken root in my mind and is germinating seems to be that the most important concept is the line of pull and it's relationship to the center of gravity of the tractor. So, without trying to let this idea sit and turn completely opaque with a firm understanding of forces and reactions, it seems that the lower the angle of pull, the less torque will be placed on the rotating axel and thereby reducing the chance of a catastrophic rotation and flipping of the tractor. My Wile E. Coyote mental image is that a large angle between the pulled object and the point of attachment will generate a downward pull at the attachment point to put it in the line of pull between the pulled object and the axel.

If I am subconciously comprehending this properly, then the longer the chain, the smaller the angle and the lower the force required to put the attachemnt point in the line of pull.

Did that make any sense to anyone else?

That is how it would appear to work. I think a short chain would be safe if it is a straight pull. If the object is on the ground, like a drag or log, i think i would give the chain/linkage a little more length. Nothing starts to flip a tractor quicker than dragging a log up a hill.

Okay, now that I think about it, I can see the pinon gear lifting the tractor. I still maintain that it's the downward force on your pulling point that causes the front to lift. If you keep your pull linkage straight, and watch for lifting on what you are pulling, you should be able to keep the tractor from flipping. It's not that easy to do, unless you start pulling and lifting at the same time.

 

[thatguy]

This thread is almost as controversial/argumentative as the 'will a plane take off on a treadmill' thread on the ar15 forum a while back lol

brian

 

[Don87]

I think absent video of a tractor actually flipping over backward, even though his load is hitched below the rear axle, we will still have skeptics. Heck, I'm not a skeptic, but I'd still like to see such a video ... not a guy getting hurt, just proof that it can happen. The tractor in my sample video would of course have a ROPS, & the driver would be belted in :thumbsup:

Tractor pull gone wrong - YouTube

http://www.youtube.com/watch?v=q8sqisHb7cY&feature=related

Close: http://www.youtube.com/watch?v=6-KQUjCwsA0

 

[SPYDERLK]

Cant say Ive seen seen a cogent discussion of fixed drawbar length - altho FMJ and perhaps XTN mentioned it. The drawbar must be somewhat below the rear axle and its end must extend rearward out beyond the circle made by the tires. This will prevent a back tipover in all cases except [perhaps] a running start. Previous discussions:
http://www.tractorbynet.com/forums/safety/189672-what-causes-flip-overs.html

 

[Degolyerent]

Cant say Ive seen seen a cogent discussion of fixed drawbar length - altho FMJ and perhaps XTN mentioned it. The drawbar must be somewhat below the rear axle and its end must extend rearward out beyond the circle made by the tires. This will prevent a back tipover in all cases except [perhaps] a running start. Previous discussions:
http://www.tractorbynet.com/forums/safety/189672-what-causes-flip-overs.html

Not 'all' cases

 

[SPYDERLK]

Not 'all' cases

Please describe a situation that would cause a tractor to tip over backward when pulling from a fixed drawbar fastened below the axle and extending back far enuf that its end, and therefore the pull point, is outside the circle made by the tires.
larry

 

[JoeL4330]

Please describe a situation that would cause a tractor to tip over backward when pulling from a fixed drawbar fastened below the axle and extending back far enuf that its end, and therefore the pull point, is outside the circle made by the tires.
larry

is your point that the fixed draw bar becomes a "wheelie bar" ? ....and won't let the tractor complete the backflip?

 

[Don87]

Please describe a situation that would cause a tractor to tip over backward when pulling from a fixed drawbar fastened below the axle and extending back far enuf that its end, and therefore the pull point, is outside the circle made by the tires.
larry

Not trying to be argumentative or anything, just trying to provide info to tractor users.

But with that said, if the drawbar is attached to the tractor, isn't that the real hitch point?
I understand that the drawbar can be made 3 feet long, and below the axle, but the main problem seems to be that the tractor can gain traction, thus spinning the rear wheels on their axis............causing a flipover.
The only thing I can see is that a long drawbar..........may act as a 'wheelie bar' of sorts, and could prevent a backwards flip, but could in turn cause a sideways flip when the drawbar hits the ground............couldn't it?

 

[k0ua]

This is interesting, pulling a near immovable object from a standing start. instead of the usual easy to start, but hard to keep going type of tractor pull.


Tractor pull with David Allan Coe soundtrack - YouTube

James K0UA

 

[Degolyerent]

Well you said ' all' cases, but what if the tractor were on runners with no ground under it or even very soft ground, my point is never say' all' cases

 

[xtn]

Seems to me that any normally found drawbar length would stab in the ground and not act as a wheelie bar at all.

xtn

 

[Reg]

Maybe we should put it this way: Until there is absolute certain proof that there is some way to connect a to-be-pulled object to your tractor such that it can not flip over backwards ... everybody should assume it can happen :thumbsup:

...and THAT way is to ensure that the geometry is "right"

There needs to BE a draw bar.
It needs to be long enough to just about reach the ground before the tractor (with driver, ballast, etc) center of mass gets close to vertically above the rear axle center line.
I am NOT saying that it needs to serve the purpose of a wheelie bar, it just needs to ensure that a stable equilibrium is reached.

Idiots doing Garden tractor flips on You tube aside.
That shouldn't have passed entry inspection.
Gee, I wonder if there even was a safety inspection.

 

[Don87]

...and THAT way is to ensure that the geometry is "right"

There needs to BE a draw bar.
It needs to be long enough to just about reach the ground before the tractor (with driver, ballast, etc) center of mass gets close to vertically above the rear axle center line.
I am NOT saying that it needs to serve the purpose of a wheelie bar, it just needs to ensure that a stable equilibrium is reached.

Idiots doing Garden tractor flips on You tube aside.
That shouldn't have passed entry inspection.
Gee, I wonder if there even was a safety inspection.

The first link I posted was a tractor pulling contest.

Tractor pull gone wrong - YouTube

The second link was in fact 'idiots' that probably said "hold my beer and watch this".

The third link was also a tractor pulling contest. 100_0010.MOV - YouTube