1/4 Eliptical springs

[Ted Brown]

I do know the exact difference between a sway bar and a Panard bar, but most people here use the word sway bar in place of panard bar, sometimes you are right in people not knowing the difference between the too.. Glad you explaned it in the right way, let's hope people will refer to them by their correct names, Just like MOTORS are not what we run in TBuckets, usually, but ENGINES... Motors are electric...

 

[fluidfloyd]

ouh506,

Try this link for your spring calculations. hope this will help you out.

Leaf Springs - DiracDelta Science & Engineering Encyclopedia

George

 

[Todd]

Just to make it a little more clear, some refer to the panhard bar as the track bar or locater bar.

 

[fluidfloyd]

LumemAl,

10,000,000 is the modulus of steel. That is a constant and never changes regardless to type or heat treat, thickness or length of steel. All materials have a modulus number. Titanium is about 1/2 of steel, Aluminum is about 1/3. Hope this clears up your calculation.

George

 

[Ted Brown]

Just to make it a little more clear, some refer to the panhard bar as the track bar or locater bar.

Yes there are waaaay tooo many names for the same things now days,,, keeps people in the dark so to speak, Just say it in english, plain and simple, so that everyone understands, if thats possible... hehe What is supposed to be correct, in any book, many times it does not work on a real street rod or race car...
I like what works best, whether it is right or wrong, by the book (who's Book??)... Drag racers threw out the book a long time ago, as it proved out to be all wrong.

 

[LumenAl]

FluidFloyd...

Thank you for the information... based on that, I built an excel spreadsheet that would allow me to change spring lengths, leafs, etc and instantly get the spring rate rounded to closest pound... it works like this (top screen is all it is, shown multiple times to show it being filled out)...

I'd be happy to email it to anyone that might want it...

 

[ouh506]

Thanks to all for some great information.
LumenAl- The 305# in the last box will be the weight that the spring will surport??

Thanks again,Fred

 

[RexRod]

I could be wrong, but that last value of 305 should have the dimensions of pounds over inches, or pounds per inch. What that means is it takes 305 pounds to deflect the spring one inch. 610 pounds to deflect the spring two inches, 915 pounds to deflect the spring three inches, and so forth.

Hope that made sense.

David

 

[fluidfloyd]

AlumenAl,

I need to apologize to you as I have had brain fade. I woke up this morning and realized that I had given you a bad number
for the modulus of steel. It should be 29,000,000. I really don't deal with leaf springs and rarely find myself needing to
manually calculate them. All the cars we build use coil springs or torsion bars. I used to run them on a hand calculator
but some years ago I bought a hand computer that was preprogramed to calculate all types of suspension problems
except leaf springs. Once you quite using the math long hand it seems to escape your memory bank. As they say,
Use It Or Lose It. Guess I lost it. I'll look into leaf spring design tomorrow and forward it then. I do have a formula here
at the house but I have to figure out how to post a PDF file. Leaf spring design can get tricky at best due to the many
varibles involved. The old tyme way was to just go measure someone else's car and the head to the wrecking yard. We
are hot rodders and there's nothing wrong with that. Remember, these are not world class racing cars. They are what
they are, Hot Rods that are meant to be driven for fun. Now, let's build some cars and have fun. Again, my aplogies
and please don't shoot me.

George

 

[RocknT]

------------:welcome:

 

[fluidfloyd]

At least it was a fellow Texan doing the shootin'

 

[RocknT]

Shoot first then if you are a bad shot ask questions ,,LOL