Slopes and tractor tilt

[nebraskasparks]

Here's some documents that came from a discussion labeled How to Kill Yourself without Knowing

We have data that says we can flip a tractor to a point of no return in 3/4 of a second on dry level ground doing things we shouldn't be doing. We'll be on our back in another 3/4 of a second which means the total maneuver takes 1.5 seconds and can be "much quicker" provided the surface conditions are not dry, the ground is not level etc.

We've documented that it can take up to 5 seconds to react to a startling situation that we have not anticipated.

Isaac Newton and Albert Einstein's theories apply to tractors and aircraft in many of the same ways.

Documentation is as follows:

CONTRIBUTIONS TO THE STUDY OF THE DYNAMICS OF AGRICULTURAL
TRACTORS EQUIPPED WITH FRONT-END LOADER AND REAR FORKLIFT LOADER
Simion Popescu, Nastase Sutru
Transilvania University of Brasov/Romania, Faculty of Alimentation and Tourism
simipop38@yahoo.com, sutru_nastase@yahoo.com

www.harristechnical.com/articles/human.pdf

Driver Reaction Time by Dr. Marc Green

Personal experience with F-4 accident from 250 feet

Jerry Miculek - S&W Demo - Parte 1 - Bing Videos

National Ag Safety Database - Tractor Overturn Hazards

Visual Expert Human Factors: Driver Reaction Time
__________________
Safety first!
Proverbs 1:32
"For the waywardness of the naive will kill them,And the complacency of fools will destroy them.
Keep your ROPS up, your bucket low and plenty of weight to counter your FEL...
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Old 11-07-2010, 11:41 AM

 

[MoreCowbell]

A FEL is always to your detriment on a sideslope. All of its weight is forward and some of it overhangs the front axle. All stability comes from the rear. The more and further weight is shifted forward the worse it is for stability. At least remove your bucket if its QA. Most effect for least effort. :thumbsup:
larry

I know that this thread has morphed a littel since Spyderlk's post, but I want to say that he is 100% right IMO. If we are talking about something rolling over, we need to look at the axis around which it is rolling. When your CG is over the roll axis, that is when you start rolling. So its not just the height of the CG that is important, but where it is in relation to the roll axis.

Since the front axle on the tractor pivots around its center, the roll axis is a line drawn from the bottom of the downhill rear wheel and up through the front axle pivot bolt (picture a tractor starting to roll and you'll see what I mean). It proceeds forward on that same angle, which is toward the uphill side.

Hanging any weight off the front would move the CG forward. Since the roll axis moves toward the uphill side as you move towards the front of the tractor, simply moving the CG forward brings the CG more and more over the top of the roll axis and closer to the tipping point.

 

[dennis52]

I know that this thread has morphed a littel since Spyderlk's post, but I want to say that he is 100% right IMO. If we are talking about something rolling over, we need to look at the axis around which it is rolling. When your CG is over the roll axis, that is when you start rolling. So its not just the height of the CG that is important, but where it is in relation to the roll axis.

Since the front axle on the tractor pivots around its center, the roll axis is a line drawn from the bottom of the downhill rear wheel and up through the front axle pivot bolt (picture a tractor starting to roll and you'll see what I mean). It proceeds forward on that same angle, which is toward the uphill side.

Hanging any weight off the front would move the CG forward. Since the roll axis moves toward the uphill side as you move towards the front of the tractor, simply moving the CG forward brings the CG more and more over the top of the roll axis and closer to the tipping point.

And having a 600lb brushog mounted low and well rear of the tractor (with fel), should act as a counterweight and move the CG back to the rear.

 

[Boeing]

Thanks for all this input and thought. One last....well, maybe not...question. If the front end loader is just inches above the ground....wouldn't it contact the ground at the earliest roll tendancy? Thereby acting as an "outrigger" Another idea is ADDING weight to the rear impliment? (or stay off the dam hill) thanks:ashamed:

 

[RoyJackson]

Thanks for all this input and thought. One last....well, maybe not...question. If the front end loader is just inches above the ground....wouldn't it contact the ground at the earliest roll tendancy? Thereby acting as an "outrigger" Another idea is ADDING weight to the rear impliment? (or stay off the dam hill) thanks:ashamed:

Maybe it would act as an "outrigger", but I wouldn't bet my life on it...

 

[North Country]

Maybe it would act as an "outrigger", but I wouldn't bet my life on it...

I wouldn't even bet my tractor on it.

 

[TripleR]

Thanks for all this input and thought. One last....well, maybe not...question. If the front end loader is just inches above the ground....wouldn't it contact the ground at the earliest roll tendency? Thereby acting as an "outrigger" Another idea is ADDING weight to the rear implement? (or stay off the dam hill) thanks:ashamed:

I was thinking of that the other day as I was working on some slopes repairing wash outs and like the others, there are just so many variables that I prefer not to count on it. It may very well do so, but you have to pick it up to get out of there anyway. I was moving material and had to have the FEL on and used it to "steady" the tractor a couple of times, but it sure is nerve wracking.

 

[Reg]

Thanks for all this input and thought. One last....well, maybe not...question. If the front end loader is just inches above the ground....wouldn't it contact the ground at the earliest roll tendancy? Thereby acting as an "outrigger" Another idea is ADDING weight to the rear impliment? (or stay off the dam hill) thanks:ashamed:

This is the 4-point landing HOPE (prayer ?).
I really do think that it(the FEL and bucket) would be getting you out of a situation that it had (helped to) get you into.
Having landed the bucket, you still need to recover the tractor, but you now have the time for a few deep breaths and some careful planning.
The tractor IS more tippey with a FEL and bucket on, so you are faced with a better chance of recovery at an earlier stage.

I could argue it either way - - and from time to time DO argue it BOTH ways (-:

One thing that keeps running through this thread is that we deal only with known single dimension slopes, known C of G, known tipping points, etc. and that we can calculate and predict it all.
The reality is that these things CHANGE with different implements, different ground contours, different rocks, roots, gopher holes, etc. as we move.
Every FOOT of ground covered can be different, knowing that you are on an n% slope and your C of G is x inches above your axle center line is pretty much useless knowledge.

 

[SPYDERLK]

Thanks for all this input and thought. One last....well, maybe not...question. If the front end loader is just inches above the ground....wouldn't it contact the ground at the earliest roll tendancy? Thereby acting as an "outrigger" Another idea is ADDING weight to the rear impliment? (or stay off the dam hill) thanks:ashamed:

Yes, but less promptly than you might think. The bucket rises some during a tip owing to the FEL attachment point on the tractor well rearward of the front pivot. Also, there is some play in the FEL before the slop between supporting weight and applying downforce is taken up. Skimming the ground is good -- an inch is ok -- a few inches will likely scare you real bad but would still probably save you.
larry

 

[kday64]

So I have often joked with my friends that "surely can't be the dumbest person ever to try this".

It appears that amongst those there on TBN "I am." I am a believer that following the manual will save me $250 and the time associated with an insurance claim.

Straight up and straight down steep inclines always facing down.

If you want to add stability put several hundred pounds under you tractor on a rail and pulley system such that you can move the weight from 24-36" outboard on either side of the tractor. (Place the weight on the up hill side.) Assuming you are transversing along the side of the hill.

~Kevin

 

[Baby Grand]

...<snip>... If you want to add stability put several hundred pounds under you tractor on a rail and pulley system such that you can move the weight from 24-36" outboard on either side of the tractor. (Place the weight on the up hill side.) Assuming you are transversing along the side of the hill.

~Kevin

Brilliant! I'll tell The Plant Manager that I don't just want the backhoe for doing some projects - I really need it for safety on slopes!

 

[Boeing]

Movable "upside weight" is a GREAT idea.....though where/what would you use for "hundreds of pounds" of weight, how would one suspend it to run it back and forth on this rail. I like it though The back hoe would also be a great movable weight...but it's hard to bush hog with a back hoe:laughing:

 

[MoreCowbell]

... If the front end loader is just inches above the ground....wouldn't it contact the ground at the earliest roll tendancy? Thereby acting as an "outrigger" Another idea is ADDING weight to the rear impliment? (or stay off the dam hill) thanks:ashamed:

I think if the FEL bucket was low enough and not in float mode it could have a stabilizing effect. When the tractor starts to roll, the downhill side of the bucket hits the ground which shifts the roll axis to a line between the bottom of the downhill rear wheel and the downhill side of the bucket. At that point, your CG would be further to the uphill side of the roll axis than before the bucket contacted the ground.

This would give you stability similar to what you would have with a non-pivoting front axle. It makes me think of whether it would be good to have a device to temporarily lock the front axle pivot to get added stability in certain situations.

I can think of a couple reasons why that would not be practical. Added cost and added stress on the chassis due to twisting forces. Still, it would make the tractor more stable on slopes though.

 

[North Country]

Still, it would make the tractor more stable on slopes though.

Until the downhill front tire drops into a hole and the only thing left on secure ground is your uphill front tire. The pivot line instantly moves uphill and you'd have an instant rollover.

 

[MossRoad]

If any of you ever get the chance to drive an articulated 4wd unit like a Power Trac, Ventrac or Steiner on a side slope, please take the opportunity.

Read this post from the past when you get a chance. It is very enlightening....


http://www.tractorbynet.com/forums/related-topics/5108-compact-tractors-designed-all-wrong.html

 

[moored4]

As far as the relationship of %/degree of slope as discussed early in this thread, one foot of fall or rise in 100 ft equals a 1% slope. 10ft in 100 = 10% and is 5 degrees, 100ft in 100ft is a 100% slope but only 45 degrees. I tried copying it to post but couldn't, so here is a link to a chart that explains it completely.
www.co.cowlitz.wa.us/buildplan/forms/Calculating Slope.pdf

I can't belive our county planning department has anything worth while! We here don't think very highly of them! But! It's a good chart!

 

[SPYDERLK]

Thanks for all this input and thought. One last....well, maybe not...question. If the front end loader is just inches above the ground....wouldn't it contact the ground at the earliest roll tendancy? Thereby acting as an "outrigger" Another idea is ADDING weight to the rear impliment? (or stay off the dam hill) thanks:ashamed:

Yes, but less promptly than you might think. The bucket rises some during a tip owing to the FEL attachment point on the tractor well rearward of the front pivot. Also, there is some play in the FEL before the slop between supporting weight and applying downforce is taken up. Skimming the ground is good -- an inch is ok -- a few inches will likely scare you real bad but would still probably save you.
larry

I think if the FEL bucket was low enough and not in float mode it could have a stabilizing effect. When the tractor starts to roll, the downhill side of the bucket hits the ground which shifts the roll axis to a line between the bottom of the downhill rear wheel and the downhill side of the bucket. At that point, your CG would be further to the uphill side of the roll axis than before the bucket contacted the ground.

This would give you stability similar to what you would have with a non-pivoting front axle. It makes me think of whether it would be good to have a device to temporarily lock the front axle pivot to get added stability in certain situations.
I can think of a couple reasons why that would not be practical. Added cost and added stress on the chassis due to twisting forces. Still, it would make the tractor more stable on slopes though.

I will remain a vicarious member of the empirical study group. ... It sure would be nice if the stops were adaptive to slopes, acting to damp and limit downhill pivot. Tractor designers could invent this feature. It would make the tractor much more stable.
larry

"---- "

These things may have been covered previously. :confused3:
larry

 

[JWR]

Not the SLOPE as much as a sudden CHANGE.
Look for roots, rocks, etc on the high side, look for dips and gopher holes on the low side.
Do NOT be staring at a goofy gauge.
If it feels bad then it IS bad.
Seat belt if you have ROPS, no seat belt if you don't have ROPS (better chance of being thrown clear).
Keep the bucket and anything on the 3pt low and be ready to dump them QUICKLY.

Probably the HARDEST thing is to steer DOWN the slope if/when things get really hairy.
However counter intuitive this may seem at the time, steering UP the slope is more likely to roll you.

REG has it right. Especially watch for what might become a sudden change such as a hole on the lower side, a groundhog hole complex, a small log that will roll with you, a big rock, etc.

1) Keep the bucket and anything suspended from the tractor low as possible.
2) If you can't go up it in 4wd due to wheel spin then you can't control your machine on that slope. Test it.
3) Steering to the downhill is your main exit strategy and you better plan for when that is or is not feasible. Not feasible if it leads to something worse like water or a steeper slope or trees.
4) I'm not for seat belts. Cars YES, tractors, NO. Watching the Penn State safety demo at Ag Progress days in PA the dummy on the remote controlled tractor is OK after the tractor rolls over because he had the belt on and his ROPS up. (Great demo!) The problem is there is an infinite variety of situations and being strapped down by anything amounts to a hazzard. It is a tough call but being ready to jump appeals to me. Still, I have lost a few friends to tractor rollover -- none wearing seat belts and all VERY experienced. Not a simple choice. You have to make your own call.
5) I am told that 15% slopes are some sort of ISO/ASME spec. If that is true then throw away ISO specs. Hill country farmers are routinely found on slopes exceeding 40% without even giving it much thought. I measured a couple of places considered "steep but no where near prohibitive" and definitely very safe for a decent tractor and they averaged 40%. I've operated 4wd tractors of JD and MF brands on considerably steeper slopes than that (but only up and down) with no problem. The 40% slopes are OK sideways if your rear wheels are out enough. Tire spacing and cg height are the whole ball game for going around hills sideways. CG is hard to measure or know.
6) You better have brakes that will hold the machine. I often find it compelling to ease down some VERY steep spots using brakes in 4wd where all 4 tires grab. You can let yourself down over sudden drops, shelfs, etc. safely where "clutch out motion" is not safe.
7) While keeping that bucket low, be careful not to have it so low as to dig in going down a steep slope ! A sudden unplanned digging dive of the bucket can ruin your day as well as end your life. Keep the bucket low but "Tips up" is good advice in both tractor operation and skiing.
8) Can you keep your engine running ? There are tractors on the market, brand new, that (until the mfr comes out with product improvement kits) will starve for fuel trying to go up a 40% slope while carrying 1/3 tank or more of fuel. Dying engine and lousy brakes are a bad combo on the steep. Was that a pond behind you !?

 

[JWR]

I was not able to find anything using your example of how to figure slope.

Grade (slope) - Wikipedia, the free encyclopedia

It looks like a 45 degree slope is a 100% grade, because it's rise and run are equal. See File:Grades degrees.svg - Wikipedia, the free encyclopedia Not even sure if 90 degrees would be a slope since there is no run to it.

1) You are from Buckhannon so you know what steep means. That's a plus.
2) I mow near Lost Creek.
3) Yes, a 45 degree slope is a 100% grade. I searched the definition quite a bit (finding many WRONG answers too) and % slope is defined as drop divided by run. In other words my 62 inch piece of 2x3 is up in the air 25 inches on one end when level and thus indicating a 40% slope. 25/62 = roughly .40
4) A chapstick as a roller works for a level on that 2x3 if you don't carry a level around. It also works on end to hold up the gas pump lever when some safety expert thinks you can't handle the responsibility of a notch to hold up the lever while the gas flows. *** covering lawyers ...
5) Pros of course will have laser levels and a transit ...
6) Don't worry about a 100% slope. If your tractor ever gets on one you won't be there but a second or two.

 

[Boeing]

Guys, I had to post this.....
I ordered and installed an "inclinenometer" on my Kubota last week. The slopes that had initally concerned me are only 15%. (I had gotten used to them) The ones that made me pucker are 25% and MUST be taken in "turtle and 1st gear". A few times I would sink in a hole and it would go to 30% where I would immediately do the down hill steer manuever. I'm using % because I have no DEGREE key. Now that it is installed I will recommend it to everyone.....it's definately an asset and a tool.:thumbsup: