The Fox Shock Perch Adjustment Mod

[Raptor1]

Ok ,if physics is a law then humming birds should be put in prison,because they defy the "laws of physics".

 

[frogslinger]

Ok ,if physics is a law then humming birds should be put in prison,because they defy the "laws of physics".

An oft quoted but innacurate statement... (plus it is usually about bees)

For the statement to be accurate it would be... a bee with fixed wings and a method of propulsion cannot fly at the speeds at which a bee flies.

The problem is that a bee does not fly using the traditional fixed wing formula of lift drag thrust and gravity that a fixed wing airplane does... it flies in a manner similar to a helicopter where lift is generated by the bees wings motion relative to its body...

Using that much more complicated set of equations you can explain the motion of bees and hummingbirds and helicopters (and anything else that flies at extremly slow speeds, relies on a column of air or has non fixed wings)...

The older simpler formula cannot explain how a bird flies either... lift at take off would in theory be zero, as the birds speed is close to zero...

They do however describe very well how a bird glides... and why a bee cannot.

 

[FSM06]

 

[FSM06]

pssssst..............raptor1, I think it is your turn.

FSM

 

[Madcowranch]

 

[MarkT]

SNIP

now to refute your refutations...

Ok... I totally agreed that it would not change the spring rate in this application... I was simply arguing with your laws of physics thing... and I can back it up...

SNIP

it does demonstrate the rate thing though even if you do not want to admit it... those numbers would be accurate and if you plotted a graph of average spring deflection vs load it would show a nice curve that anyone could point to and say... yup getting stiffer...

SNIP

I was only trying to show that a spring could get stiffer as load increased... which coupled with my example above simply disproves your laws of physics comment...

SNIP

So you do not agree that is how a progressive spring operates? Cause it is...

SNIP

frog... I'm not really sure why you keep trying to take my comments out of context and then prove me wrong? For example, why do you keep trying to disprove my "laws of physics" comment? My original comment, taken in the context of which is was written is 100% true. I never said that "springs that change rate with load defy the laws of physics" or whatever it is you are trying to turn my statement into. Nor did I ever say there are not any conditions under which adding preload could change the spring load at ride height thereby affecting ride quality... I was speaking specifically of the Raptor and what effect moving the spring perch one notch has.

That said, I firmly believe that everyone has the right to create their own reality! Let's make a quick analogy... spoken language... someone can make up new words for everything if they want to. They can say that most leaves on trees are blue. (But most people would say, no, most leaves on trees are green.) They also have a right to come up with a crazy way to graph springs and to come up with the "ridiculous" and even to manufacture realities to "prove" their theories... But engineering has a "language" very similar to spoken language. Calling leaves blue doesn't make them blue in the "real world" just as making up ways to analyze coil springs doesn't change the reality of how springs are analyzed in the "real world".

Continually changing the context, taking statements out of context, creating your own definitions, and dreaming up meaningless ways to present data that give the illusion of proving your theories really only proves to me that you are good at making stuff up that sounds like it could be true... have you ever considered a career as a statistician or speechwriter for a politician?

For example: A progressive coil spring would graph as a curve on a standard spring deflection vs. load graph... But graphing spring deflection vs. load for your example spring would actually result in perfectly straight lines showing constant spring rates... not a curve.

But you decided to use average spring deflection for your graph. This seemingly small detail (graphing "average" deflection instead of plain deflection) would result in a curve as you stated...

those numbers would be accurate and if you plotted a graph of average spring deflection vs load it would show a nice curve that anyone could point to and say... yup getting stiffer...

The reality is that anyone looking at the curve on your graph would get the false impression that the spring was getting stiffer...

As far as progressive coil springs... you said:

"a progressive spring would be more like stacking a 200 on top of a 250 on top of a 300 on top of a 400 etc all the way up to 2000... "

And in this post you reaffirmed that is how a progressive coil spring works. I will admit that what you said "sounds good"... like it could be true... I mean, look at it... you have a stack of coil springs with each spring progressively get stiffer... Kinda makes sense? Well, it does if you've never actually worked with stacked coil springs...

I think in another post you mentioned you were a radio expert... which means you probably know something about electronics?

Think of a coil spring as a resistor. Two identical resistors in parallel (side by side) act just like two identical coil springs side by side, you double the resistance... and with coil springs, the rate would double.

But now put the identical resistors end to end... in series. Now the resistance is halved. This is exactly how stacked coil springs work (and they don't need to be welded together). But once you start talking about multiple resistors (or coil springs) with different values in series (stacked) it gets kinda complicated.

The formula for combined spring rate of stacked coil springs is the same as for calculating total resistance of resistors in series:

1 / (1/springrate1 + 1/springrate2 + 1/springrate3 +....) = combined spring rate of the stack of coil springs.

So now plug in your numbers from the stack of coil springs that you claim to be a example of how a progressive coil spring works...

What you made is a multiple rate coil spring pack that starts out with a very soft rate... much, much softer than the softest (250 lb/in) spring in your stack... around 20 lb/in. Then as each spring coil binds, you have a jump to a new spring rate... the last abrupt jump would be over a 2x increase in rate... from 990 lb/in to 2000 lb/in. This is not how a progressive coil spring works in the "real world" and is why I disagree.

As a progressive coil spring compresses, the coils of the spring progressively touch each other which gradually shortens the effective length of the steel bar that has been wound into a spring. The spring rate changes gradually as this happens. Big difference from your theory.

That said, could you come close to emulating a progressive coil spring rate curve using a stack of coil springs? Yes. But not in the way you describe.... Using your "target rate" of a 2000 lb/in spring, you could stack on several 1,000,000 lb/in springs each with progressively less travel... Then as the spring assembly compressed and each 1,000,000 lb/in spring progressively collapsed the overall spring rate would gradually increase to 2000 lb/in in a manner closely approximating a curve. Theoretically possible... but certainly not practical.

Had you said something like this as a description of how a progressive coil spring works, I would have agreed with your theory... but you didn't... instead you described a stack of individual springs with lower rates that progressively increased in rate up to your 2000 lb/in "target". Sounds like your theory might describe how a progressive spring works... but it doesn't...

Hope this didn't come across as too harsh... because it wasn't meant to be...

(let the oopstorm: begin! )

 

[FSM06]

I think I'll sit down for this one..........

 

[Floppy]

This mod would seem to negate the need for the leveling kit while still keeping warranty weary Ford Service happy.

 

[Falcon]

Cowboy
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FSM06 .. Falcon
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...:box:
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[Madcowranch]