Ackermann Principle

[Entropy]

I'm a little unclear here. Do your comments refer to a car with some ackerman or a car with 0 ackerman?

There is ether the correct amount of Ackerman or there is none. 
I of course, was referring to the correct Ackerman.
Sheesh 



So many smiliez so few posts. 

[fabr]

There is ether the correct amount of Ackerman or there is none. 
I of course, was referring to the correct Ackerman.
Sheesh 






So many smiliez so few posts. 

  But what is correct is a matter of debate.I agree the "correct" amount is when all other factors ,such as slip angle to name just one ,combine to make the ultimate setup for any particular car or car usage.

I,of course, believe that there is either correct ackerman or incorrect ackerman and no ackerman (IMO useless as it is ) is incorrect.

BUT ,I'm sure there are those that disagree.

[artie on edge]

Another dabate!!!!!  What is "the correct" Ackermann?

IMO, its like camber (for instance), you can have some, neg or pos, or none (0 deg) or any degree of inclusion... so how much inclusion is the correct ackermann?

The answer is...... ..... there is none!

Each car has its own vagrancies, its own persona and each differing car will require different levels of ackermann to reach a particular goal.

And theres another one. The goal! What does the owner or builder want to achieve? We all have different ideas on what a car should and shouldnt do and therefore we would probably never agree on a particular setup.

If I gave you my car for a year it would no doubt come back different in some way to when I gave it to you. Even though I considered it to be perfect at the time.

[fabr]

  mm:Yup.

[Entropy]

Hmmmmm....
     Goal:  Cross the finish line first.

Enjoy

[Rick S.]

OK, all of this talk and no one has really clarified this for me.
Is the positive negative and zero terminology viewed like this?
1) Positive: The inside tire turns more angle than the outside tire.
2) Negative: The outside tire turning more angle than the inside tire.
3) Zero: Both tires turning the same angle.
This is how I've always viewed it, but maybe I'm wrong.

[fabr]

Normal ackerman for cars that turn both directions is when the IS tire in a corner turns more sharply than the OS tire in a turn. This is accomplished by the steering arms being angled to the centerline of the car on a rear steer setup and by the arms being splayed to the outside of the car on a front steer setup. It is rare that you would use reverse ackerman.

[fabr]

OK, all of this talk and no one has really clarified this for me.
Is the positive negative and zero terminology viewed like this?
1) Positive:(normal) The inside tire turns more angle than the outside tire.
2) Negative:(abnormal) The outside tire turning more angle than the inside tire.
3) Zero: Both tires turning the same angle.
This is how I've always viewed it, but maybe I'm wrong.

You have it correct.

[artie on edge]

OK, all of this talk and no one has really clarified this for me.
Is the positive negative and zero terminology viewed like this?
1) Positive: The inside tire turns more angle than the outside tire.
2) Negative: The outside tire turning more angle than the inside tire.
3) Zero: Both tires turning the same angle.
This is how I've always viewed it, but maybe I'm wrong.

Yes Rick you got that correct and I guess we had better get the terminology correct also (im not trying to be nit picky), but Ackermann is the principle, Pure Ackermann is where the principle is applied in its extremis. (line through each tie rod and ball joint pivot from each side crosses at the rear axle line centre) and if the outside wheel turns in more that the inside wheel, this is know as Reverse Ackermann.

It was originally invented/devised by Rudolph Ackermann some time after 1764 to allow horse drawn coaches to manouver easier through the London streets but there is some arguement that it was in fact used earlier by an Erasmus Darwin in 1758, but really, who cares?

Incidentally Reverse ackermann is (sometimes) used in some tar track cars to cater for slip angle differences from the outter to the inner wheel at high speed. Low speed corner performance suffers as a result.

 

[fabr]

I agree that toe out on turn is a better term for any "modified" Ackerman.

[fabr]

Nit,nit,nit,nit..................

[artie on edge]

Now now Mas... control yourself. We are trying to help those who arent aware build their knowledge base...

This is an example of pure ackermann, in reality very few cars are set up exactly like this.






In truth it varies from Nil (common in dirt cars) to pure (rare) to Reverse (some tarmac racing)

[fabr]

I didn't say nit-wit.I was meaning nit,nit,nit picking. LOL! You are right and the pics are a great help,thanks.

[LiveWire]

The specific terminology for Ackermann is the exact amount which makes right angle lines from the front two tires and a lines straight through the center of the rear tires intersect at a common point. However, it is commonly accepted slang to say more or less Ackermann. It is shorter to type than 'more or less toe out on turn than perfect Ackermann'. Reverse Ackermann technically is not a valid description, but is also a common expression which people understand what is being said. The Ackermann principle does not factor in slip angle. I doubt it played a significant role on carriages. However, if someone said they had Ackermann compensated for slip angle, I would understand what they meant. I think it is easier to explain to people the common slang use of the terms rather than have them misunderstand what is being talked about.

[artie on edge]

The specific terminology for Ackermann is the exact amount which makes right angle lines from the front two tires and a lines straight through the center of the rear tires intersect at a common point.

Sorry Live... I dont understand what you are describing here. Are you referring to the first diagram?