Hill Climbing Primer

[SPYDERLK]

SPYDERLK Did you miss the detail that the brakes were firmly applied? or the axle shaft welded to the housing?

In this exchange, the tires could be cast in concrete and there will be no different result.

The example is to demonstrate that forces seen within the tractor unit do not manifest external weight shifting unti "the rubber meets the road".

... or the axle meets the road so to speak. Axle welded to chassis allows no external interaction. Thats different than freezing the tire in place by external means..
larry

 

[SPYDERLK]

Did you know that the acceleration is different for the con rod as the crank passes over TDC than when it passes BDC? "thrown rods" nearly always happen at BDC .

A humorous aside. Do you know what the engineering unit for "rate of change of acceleration" is termed?

ready.....

It's a JERK! a detail we all seem to be quite well studied in from time to time ;-)

It should be the same if the engine is just being rotated and the wrist pin is centered in the piston. But running is not just being rotated. Forces vary per stroke. Also there is less relative velocity between bearing shell and crank throw at the bottom. That would be an issue to maintaining the hydrodynamic wedge that keeps parts from touching. Strange though that failure would show instantly from that. Im thinking that the culprit is the power stroke, perhaps many cycles later after damage occurs that causes the break showing at the bottom.

I try to change acceleration smoothly. :wink:

 

[ovrszd]

It can if theres no load and the wheels are frozen in place. The tractor wants to turn the axle but the axle wont so the tractor will go around if it.can. This is much different than a load causing tip. It is concievable that net tire rotation can be backward relatve to ground, ... Also different than a load point configuration that wont allow tip.
larry

Larry, you and I are finally on the same page. I think our differences have been because I don't know how to read the page you are sometimes on. But I can clearly read this page and we agree. As for CalG, he ain't quite there yet. Still wanting to weld axles or bury tires in concrete. Not sure how that even got in the discussion and it has absolutely no relevance to me.

 

[vtsnowedin]

There are a lot of people in this debate that I would not sell a life insurance policy to. :thumbsdown:

 

[CalG]

Well, It would be nice to see the ring climbing pinion die a sudden death without compensation ...

I'm still trying to advise the transmission housing that it need not worry about being lifted by anything other than turning wheels.

By the way, Has anyone ever seen a TRACTOR rocking in the parking lot or lifting a single front wheel when pulling out?

Must be those reactive forces are all resolved "internally".....

 

[Egon]

>>> Thats just it. It cant happen when the pullpoint is below tire contact. Both the propulsion lever and the pull [load] lever bear equal force ; one pushing forward, the other exactly offseting that push by pulling back. The pull lever is longer so the net torque is to tip the tractor forward. The ring gear is factored into the push lever. Theres no other effect in a steady state or statioanary pull. Acceleration or a hill would introduce COM effects.<<

>>All side tip forces would remain as if the tractor is off. Drive and driven torque are equal and opposite.<<

It does happen when the pull point is below the tire contact.
You need to convert all dem forces that are pushing on dem levers and get dem in the right places.
Wheels within wheels.

 

[SPYDERLK]

Larry, you and I are finally on the same page. I think our differences have been because I don't know how to read the page you are sometimes on. But I can clearly read this page and we agree. As for CalG, he ain't quite there yet. >Still wanting to weld axles or bury tires in concrete.< Not sure how that even got in the discussion and it has absolutely no relevance to me.

You are not equating these, right?

 

[SPYDERLK]

>>> Thats just it. It cant happen when the pullpoint is below tire contact. Both the propulsion lever and the pull [load] lever bear equal force ; one pushing forward, the other exactly offseting that push by pulling back. The pull lever is longer so the net torque is to tip the tractor forward. The ring gear is factored into the push lever. Theres no other effect in a steady state or statioanary pull. Acceleration or a hill would introduce COM effects.<<<

>>All side tip forces would remain as if the tractor is off. Drive and driven torque are equal and opposite.<<

It does happen when the pull point is below the tire contact.
You need to convert all dem forces that are pushing on dem levers and get dem in the right places.
Wheels within wheels.

Wrong.

 

[Egon]

Wrong.

Wrong!

 

[ovrszd]

You are not equating these, right?

Larry, nope, I definitely know the difference of those two. With the welds, the desire to elevate the front is gone. With the concrete, the desire to elevate the front remains, just as it does with zero tire slippage.