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Old 04-11-2010, 09:24 PM   #16
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Why are yokomo springs junk?
well they weren't even close to what they were supposed to be and blue/black were bascially the same and yellow/pink were as well.
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Old 04-11-2010, 10:03 PM   #17
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In not 100% sure, but i think Yokomo springs are proggressive They work well on track, that all i care about
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Old 04-11-2010, 10:33 PM   #18
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In not 100% sure, but i think Yokomo springs are proggressive They work well on track, that all i care about
Hi Ant, nah they measured totally linear from 0.5mm to 5mm compression. If they work for you thats great, i was just really surprised at the results. I was going to test the whole set of Yoke springs (i have 4 of each color) because i liked the precision & quality of the BD5 car itself (the Yokomo diff is a beautiful thing!). I spent about 2hrs testing and retesting the yoke springs alone because i couldn't believe the results. I even went back and tested the HPI's and few Xrays again cos i thought something was really screwed up with my test rig but they tested fine again.
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Old 04-11-2010, 10:39 PM   #19
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for springs to truelly be progressive they have to collapse some of the coils against each other and have different "winding pattern" in the middle of the spring from one of the ends. take a look at traxxas slash springs. those are progressive. another two questions are metallurgy and sample size. how do they age( anyone who works at a hobby shop that deals with t-maxxes can tell you about saggy weak springs)? and, how consistent are these things produced?

full-size car shock springs can go millions of cycles as long as they stay within operating range. its the extreme compressions or extensions that cause deformation and weakening.
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Old 04-12-2010, 02:03 AM   #20
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Originally Posted by Besercoe View Post
Interesting results, however have you tried to run 2.8 and HPI silver back to back on a car? For me the feel is significantly different.
I agree, 2,8 xray feels absolutely NOTHING like HPI silver i would say 2,6 is more the same feeling.
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Old 04-12-2010, 02:26 AM   #21
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nah it's not a problem, the weight on the scale at 1mm compression is around 200-300g and to compress the spring to 5mm takes close to 1500g (in some cases more). 1-2 grams error doesn't matter in the slightest.

the absolute load on the spring is not critical, actually when i calculate the final rate i ignored the first reading at 0.5mm to remove the variation. It takes the same weight to compress the spring from 1.0mm - 1.5mm as it does from 4.5mm to 5.0mm, its only the relative difference that is important for these linear springs.
You qoute values such as 2.93N/mm. This means you need to apply a weight of 2.93/9.81=0.29 grams to achieve a deflection of 1mm. If your scale can not measure this accurately, your results may be off by Newtons (not fractions thereof). I had to use only two decimal places because you don't give four.

Your comment relates to obtaining the elastic constant of your spring, which on your graph is the slope of the line, but I am arguing that if your experimentally determined points have errors of a few grams, that line can vary in its slope hugely because of this indetermination. Try to plot each point with its error bars and then see how many lines can fit through these error intervals and you'll understand what I mean. Come to think of it, you really need the calibration curve of your scale to be able to claim you have determined the spring constant to that accuracy.

Not to say the companies selling us their spring do any of this. I just take their values as orientation at best.
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Old 04-12-2010, 04:34 AM   #22
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You qoute values such as 2.93N/mm. This means you need to apply a weight of 2.93/9.81=0.29 grams to achieve a deflection of 1mm. If your scale can not measure this accurately, your results may be off by Newtons (not fractions thereof). I had to use only two decimal places because you don't give four.

Your comment relates to obtaining the elastic constant of your spring, which on your graph is the slope of the line, but I am arguing that if your experimentally determined points have errors of a few grams, that line can vary in its slope hugely because of this indetermination. Try to plot each point with its error bars and then see how many lines can fit through these error intervals and you'll understand what I mean. Come to think of it, you really need the calibration curve of your scale to be able to claim you have determined the spring constant to that accuracy.

Not to say the companies selling us their spring do any of this. I just take their values as orientation at best.
I think you'll find it's 0.29kg not grams Seriously, the accuracy of the scales is not a problem.
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Old 04-12-2010, 04:41 AM   #23
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I agree, 2,8 xray feels absolutely NOTHING like HPI silver i would say 2,6 is more the same feeling.
is that the new HPI silvers or the old? I tested the new black colored paint marked ones and i can definately notice the diff between the new silvers and the old silvers too.
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Old 04-12-2010, 04:57 AM   #24
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I think you'll find it's 0.29kg not grams Seriously, the accuracy of the scales is not a problem.
You're right, my mistake, 0.29kg.

The accuracy of the scale is one error source. They may not be as much as I initially estimated, but an error analysis is imperative to know exactly how large they are.
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Old 04-12-2010, 05:26 AM   #25
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You're right, my mistake, 0.29kg.

The accuracy of the scale is one error source. They may not be as much as I initially estimated, but an error analysis is imperative to know exactly how large they are.
i get +/- 0.05% on measuring the weight. Don't make me work out the accuracy of my CNC mill
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Old 04-12-2010, 09:02 AM   #26
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Originally Posted by gameover View Post
Hi Ant, nah they measured totally linear from 0.5mm to 5mm compression. If they work for you thats great, i was just really surprised at the results. I was going to test the whole set of Yoke springs (i have 4 of each color) because i liked the precision & quality of the BD5 car itself (the Yokomo diff is a beautiful thing!). I spent about 2hrs testing and retesting the yoke springs alone because i couldn't believe the results. I even went back and tested the HPI's and few Xrays again cos i thought something was really screwed up with my test rig but they tested fine again.
Oh ok thanks for clearing that up, now i know Still cant believe that the yellow you measured states that its harder than pink. Its "suppost to be softer". Crazy stuff. But interesting
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Old 04-12-2010, 02:49 PM   #27
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is that the new HPI silvers or the old? I tested the new black colored paint marked ones and i can definately notice the diff between the new silvers and the old silvers too.
That was with the older hpi silvers, can there be a test done between the new silvers and the old ones it would be interesting to see the difference?
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Old 04-12-2010, 03:46 PM   #28
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That was with the older hpi silvers, can there be a test done between the new silvers and the old ones it would be interesting to see the difference?
Yeah i think i can borrow a set from Jords on Wed night, if i get them i'll post up the results.
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Old 04-19-2010, 03:43 PM   #29
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Although hardly the most scientific method, I used the end to end method on some Tamiya White & Blue springs against some Xray springs.

The Tamiya white came across as slightly stiffer than Xray 3.0, perhaps cloiser to 3.2 and the Blue's were slightly softer than the 3.0's (didn't have any 2.8's to hand to compare).

These were the newer? style Tamiya springs which are all white, with a small 'flash' or colour on one end, a bit like the numbers on the Xray springs.

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Old 05-17-2010, 04:03 PM   #30
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Yeah i think i can borrow a set from Jords on Wed night, if i get them i'll post up the results.
Anything yet?
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