Preventing tractor back flip

[Jay4200]

See the simplified diagram below.

If "A" moves forward, "E" will rise.

Bruce

Actually, in the configuration that the PO described, "A" would have to move backwards.

The tractor would flip over with the load attached under the axle only if the tractor is dragged backwards, and chain winds up like a spool of thread around the axle. It might happen...

JayC

 

[Reg]

It will still flip over

It will just be more of a sling-shot flipover

You're right, initially the front wheels will be driven into the ground, but then given enough rear wheel traction, something has to give. That something is the front end switching from being jammed into the ground to being sling shot (slung shot?) upward, & over.

Nope;
Not even on a cogged track.
Attend a pull some time.
Watch the front end rise, watch the draw bar lower, see the equilibrium.
You will NEVER see a tractor flip STRAIGHT over backwards at a pull.
If one somehow gets off line - that is different and it will be a weird nasty diagonal sort of thing.

 

[Egon]

It's all about angular vectors. Sorta like a rotary airline engine.

 

[orezok]

It's all about angular vectors. Sorta like a rotary airline engine.

I have a friend who has flown about as many different types of aircraft that you can imagine. He used to ferry planes for a living. He told me that one of the most wicked planes to fly was the P51. He said that the engine had so much torque and the prop was so large and had so much "bite" that you literally could roll the plane over while sitting on the ground if you applied the throttle too fast.

He said that you had to roll the throttle in slowly as you took off until the right wing developed enough lift to counteract the torque of the prop.

I can see the same thing happening in a tractor given enough torque and traction.

 

[slowzuki]

This.

Some of you keep mentioning a relationship of the axle height to the drawbar. Not important.

You've got force #1, the contact patch of the rear tires on the ground trying to push forward. And you've got force #2, the attachment at the drawbar trying to pull backwards. Since those two forces are not colinear, they result in a torque. Since force #2 is above force #1, that torque acts to rotate the tractor up and over backwards.

The only things that will prevent a backflip are the lack of either enough power or enough traction to complete the job.

xtn

 

[jonyyuma]

I have a friend who has flown about as many different types of aircraft that you can imagine. He used to ferry planes for a living. He told me that one of the most wicked planes to fly was the P51. He said that the engine had so much torque and the prop was so large and had so much "bite" that you literally could roll the plane over while sitting on the ground if you applied the throttle too fast.

He said that you had to roll the throttle in slowly as you took off until the right wing developed enough lift to counteract the torque of the prop.

I can see the same thing happening in a tractor given enough torque and traction.

They wrote that the torgue was horrible on the Jug fighter aircraft, also know as P-47....It also had a huge prop like the p-51. I am amazed when I see either one at a airshow...Plus the loud-ness of the engines.No wonder our veterans were hard of hearing. But back to torgueing tractors..

 

[Bill Hoffman]

About the only way I can see a non-flip over is if the
towing point is well ahead of the rear axle. I don't
think you'd get enough rotational force to flip the tractor
before the rear wheels broke traction. Of course, if the
rears didn't break traction, the tractor might have enough
force to still flip.

Bill

 

[kebo]

Nope;
Not even on a cogged track.
Attend a pull some time.
Watch the front end rise, watch the draw bar lower, see the equilibrium.
You will NEVER see a tractor flip STRAIGHT over backwards at a pull.
If one somehow gets off line - that is different and it will be a weird nasty diagonal sort of thing.

I'm of the opinion that the reason you rarely (if ever) see a tractor flip straight over backwards at a tractor pull, it's because the tires are almost almost always spinning, and they usually add enough weight forward of the rear axle to keep the front end about 3 ft off the ground (for best weight transfer).

Now, I also have the opinion that if you have something hooked to the rear of the tractor and it offers enough resistance, be it attached above the axle or below the axle, and with enough torque from the engine, and if one or both of the rear tires suddenly finds traction and stops spinning, that it can and WILL almost certainly flip over backwards. That may be an uncommon sequence of events, but that's why they call them accidents.

I think there are enough deceased tractor operators that would almost certainly bear witness to that, if they could only speak now. That's all I'll say about it.

 

[idaho2]

Does hooking up a chain short or long make a difference? Short being as close to the object as possible.

 

[k0ua]

They wrote that the torgue was horrible on the Jug fighter aircraft, also know as P-47....It also had a huge prop like the p-51. I am amazed when I see either one at a airshow...Plus the loud-ness of the engines.No wonder our veterans were hard of hearing. But back to torgueing tractors..

Yes, but is there anything more memorable than listening to a P51 idleing in its unique way on the runway, and when the pilot puts the spurs to it, that heart vibrating, earthshaking sound, and to watch it lift off and climb so fast and so vertical?. It is something I will never forget. It is no jet, but just about the culmination of piston powered aircraft if you ask me.

James K0UA