Hill Climbing Primer

[Egon]

Yes - And still stopping short. ... If you dont move to the final effector point -- the end of the drive lever [ground], you always leave the situation with a more complex and indirect solution. The sound byte concept walking/climbing is convenient but seems to lead directly to the simple assumption that with enuf torque coupled it will always happen. Assessing at the final effector points of drive and load quickly shows the fallacy of that assumption.
larry

Trying to confuse us uneducated boys with verbage? :thumbsup:

Just come up with a force diagram with all the forces to prove your point. Verbage in quantity doesn't.

 

[SPYDERLK]

Larry, I thought of an example where the drive gears rotation is backwards. A WD45 Allis Chalmers tractor, or many, many other models that use an additional set of gears outboard of the main gear case. These designs create a situation where the axle shafts coming out of the third member assembly are turning backward. At the outer end of that shaft is a straight cut gear. It turns a larger straight cut gear which is fastened directly to the shaft that the rear tire is fastened to. The reverse rotation of the first shaft, thru the two gears, creates a forward turn of the shaft the tire is fastened to. These tractors display the very same "light front" affect that a standard setup creates. No change in the end result.

Yes, thats what I said:

You might want to take a look at why a setup with the ring gear driven the opposite direction that the tires turn would still produce the same result.

Interesting that it is done. I thot it might be used to downsize the differential by introducing a further gear reduction afterward in the L/R axles.

 

[ovrszd]

Yes, thats what I said:
Interesting that it is done. I thot it might be used to downsize the differential by introducing a further gear reduction afterward in the L/R axles.

Sorry, I thought you implied that the reverse rotation setups did NOT have a lifting affect.

I think those setups were used for two reasons.

First being as you offered, didn't have to use as big of gear ratio change in the third member.

Second, they gained main chassis height, or what is commonly known as "row crop" design. Early Fords advertised that gain. Brands that did not use that design set their tractors on much taller tires to try to achieve that height. Was very much needed when "laying by" corn, or what is commonly known as cultivating. Could do it when the crop was much taller.

 

[SPYDERLK]

Trying to confuse us uneducated boys with verbage? :thumbsup:

Just come up with a force diagram with all the forces to prove your point. Verbage in quantity doesn't.

I explained it in previous posts. msmith1wa understood and described an example :

I am going to propose something that is not practical but takes what SPYDERLK is saying a little further.

Lets say there is an object that is to heavy or is theoretically immovable. Now lets dig a trench out from this object. Now fabricate a hitch that has the pull point below ground level. Now back the tractor up to the immovable object so that the trench is between the tires so that the hitch can be installed without dragging. Now pull on the immovable object with the tractor.

Will the tractor lift the front tires and tip over backwards? No it will not, in fact it will do just the opposite and actually force the front tires into the ground.

>>> Then you reiterated the impossible <<<...

>>>As soon as the tire's stop moving the front of the tractor goes up. It requires sufficient torque and the rear must have enough traction so they rotate more slowly than normal for the gearing being used.<<< :thumbsup:

The force contributed by the drive shaft must be included in the sum of forces and acts at the point the pinion contacts the ring gear.p:thumbsup:

Why do some four wheel drive tractors have weights on the front when just the fact the tractor is hitched low and pulling would do the same thing?

Do yourselves a favour and look at a picture of a ring gear and pinion. What happens when the ring gear is locked in position as would be the case with sufficient traction!

View attachment 371314

[Were seeing the reason the gear climb description is a problem.]

... I dont think youre going to be able to break free of it.

 

[CalG]

What I don't get is why the tractor doesn't tip over sideways as the transmission input shaft tries to "walk around" the first gear on the lay shaft.

It seems that that is where the engine power is the most direct!

;_)

Really, I do get why,..

but pulling trees up hill is a task worth considering carefully. The OP has more information than one can shake a stick at. Hopefully a prudent operator would hitch low, carry low and go slow. that and stay off the side slopes! For ALL the reasons discussed

 

[ovrszd]

What I don't get is why the tractor doesn't tip over sideways as the transmission input shaft tries to "walk around" the first gear on the lay shaft.

It seems that that is where the engine power is the most direct!

;_)

Really, I do get why,..

but pulling trees up hill is a task worth considering carefully. The OP has more information than one can shake a stick at. Hopefully a prudent operator would hitch low, carry low and go slow. that and stay off the side slopes! For ALL the reasons discussed

I assume you are just trying to be funny.


But then,,,, if you don't know why the front tries to lift under power, you probably also do not know why the machine in fact does try to tip over sideways. This action is not visible on a vehicle without suspension but it is very noticeable in all others. Especially those with high torque engines such as big bore gassers or diesels. Go sit in a truckstop for 5 minutes watching the Semis come and go. You'll see both actions live and in person.


In an attempt to use examples that you might be familiar with, I also reference Super Stock cars at the drapstrip. Explain to me why they lift the left front tire first, then lighten the entire frontend and shift all that weight into traction to the rear tires???

 

[CalG]

I assume you are just trying to be funny.


But then,,,, if you don't know why the front tries to lift under power, you probably also do not know why the machine in fact does try to tip over sideways. This action is not visible on a vehicle without suspension but it is very noticeable in all others. Especially those with high torque engines such as big bore gassers or diesels. Go sit in a truckstop for 5 minutes watching the Semis come and go. You'll see both actions live and in person.


In an attempt to use examples that you might be familiar with, I also reference Super Stock cars at the drapstrip. Explain to me why they lift the left front tire first, then lighten the entire frontend and shift all that weight into traction to the rear tires???

Why those are examples of INERTIA at work.

If those durn drag cars weren't in such a big hurry, why I bet a fellow would never know they had such big engines in them.

Exactly the same reason why the cars at the drags "lift their front ends. The contact patch is below the center of mass, and that contact patch is trying to be in a place up ahead that the center of mass is not quite prepared to go at the same time.

Perhaps confusion over dynamics and statics is the root of all these comments.
One takes calculus, the other just needs to solve triangles ( force vectors) .

It's easy enough for me to simplify a slow moving tractor to the condition where statics describes everything.

Now that speeding drag car or the rocking big rig. I would need to call on "the calculus". to describe the results.
Lets not get all "wound up" in hotchkiss drives and the need for ladder bars or I'll just be beside myself.....;-)

 

[ovrszd]

Egon and my points are simply that there is no need for calculus or dynamics or statics or vectors or triangles or any other such methods of description. It's very simple. I was just curious if you could explain it. But now I'm not sure.

I scrounged thru my boneyard but couldn't find an intact third member. I'll check at my Son's shops and if I find one I can explain it all with 30 seconds of video, no charts, graphs, vectors or formulas. Just simple logic.

 

[Egon]

Egon and my points are simply that there is no need for calculus or dynamics or statics or vectors or triangles or any other such methods of description. It's very simple. I was just curious if you could explain it. But now I'm not sure.

I scrounged thru my boneyard but couldn't find an intact third member. I'll check at my Son's shops and if I find one I can explain it all with 30 seconds of video, no charts, graphs, vectors or formulas. Just simple logic.

I've explained it more than once. I've also sat on tractors hitched low with the front wheels off the ground.

 

[Egon]

I assume you are just trying to be funny.


But then,,,, if you don't know why the front tries to lift under power, you probably also do not know why the machine in fact does try to tip over sideways. This action is not visible on a vehicle without suspension but it is very noticeable in all others. Especially those with high torque engines such as big bore gassers or diesels. Go sit in a truckstop for 5 minutes watching the Semis come and go. You'll see both actions live and in person.


In an attempt to use examples that you might be familiar with, I also reference Super Stock cars at the drapstrip. Explain to me why they lift the left front tire first, then lighten the entire frontend and shift all that weight into traction to the rear tires???

Engine rotation forces transferred to the frame.