Snappy or Poppy Skis

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Cadman
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Location: Crystal Mountain, Washington

Snappy or Poppy Skis

Post by Cadman » Mon Sep 23, 2019 10:22 am

I know that a lot of skis are built these days with two layers of titanal which tends to make them smooth and damp. ( and they tune well)
However, I have skied on some metal layered skis that have no snap to them while others seem to be quite poppy. It does not appear to be extra camber that is making them poppy. What kind of things can you do to a ski design to make it damp but still pop out of the turn? Head seems to have a good handle on this.

barnboy
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Re: Snappy or Poppy Skis

Post by barnboy » Tue Sep 24, 2019 7:39 am

The obvious (sorry) answer might be to get your hands on some of the Head skis that you think meet the grade and peel those suckers apart. If you spread the word to your local shops that you're looking for one I bet it won't take you too long to get your hands on a broken ski. Or maybe just shell out for a used pair on e-bay?

Build-wise, I still believe camber underfoot is #1, core make-up/taper is #2, fg/cf choices and placement #2a, resin system #3 (and then heat/pressure, cure cycles, etc...)

Snap and Pop, or live vs dead is something, as a builder, I'm always chasing and tinkering with. Whenever I'm on any other company's skis or boards it's the first thing I'm feeling for. Lately, I've been focusing on increasing dampening towards the ends of the skis and decrease dampening within the running length or effective edge zone.

In my mind, Ash stringers go a long way towards upping the pop and are cheaper than cf. That being said, I've never built a ski without cf strands in it... which makes it difficult for me to parse out what the cf does or does not do. Along with the Ash stringers (in an otherwise Poplar core) I tend to leave a little more meat on the bone when I want to up the potential energy. I'll work at or around 11.2mm - 11.5mm as a max thickness when I'm concerned about making sure there's plenty of pop in there, especially for "larger" folks (be it size, stature, or style).

I do use VDS wrapped pieces (2) of titanal in the binding zone, but I pocket them in the core, and use fg above and below (core/fg/VDS/titanal/VDS/fg) the titanal pieces. I use pieces, rather than one long piece as a way of reducing the sheer forces the titanal is exposed to, and to break up the dampening effect it may have on the overall ride. I also only use topside, which I know results in an asymmetrical laminate, which is another reason why I split the titanal into 2 pieces... it's far more "feels right" than anything that I can explain with physics or rules.

I also have taken to breaking up the cf layers in most builds as well... I'll use sections of bands pre and post binding zone above and below the core. I reserve tip to tail cf layers for only the poppiest of builds. This also "seems" to help me pull the geometry I'm looking for from my forms while adhering to my time tested heat/pressure ramp-up cycles.

I agree with you that camber alone is not an indicator for pop... but I would immediately wonder what's going on inside with those skis that have a decent amount of camber underfoot, but are low on the pop-scale... for example, I know when I've built with bamboo I've had a very difficult time getting anything but a "soft" ride. As springy as they may feel in my hands while doing the ever-popular wheelie flex test, they tend to just dampen out on the snow. I know ON3P (and undoubtedly others as well) build insanely awesome and plenty poppy skis using boo, so I'm guessing their fg/cf choices and resin system are doing a lot of the work? Or perhaps their cores are laminated/produced in a different manner than the ways mine were? I moved away from boo to more "traditional" hardwoods as a manner of hoping to identify what role the core may actually play in the behavior/feel of the finished part.

14 years in and most of this stuff is still a bit of a head-scratcher to me... I have come to understand much of the theory behind why certain builds SHOULD deliver certain results... I can also explain to you why I THINK the way I do things deliver certain end results. But the only thing I know for sure is that there are so many things at play here, and the fewer variables you can change while trying to identify the role something may play in your finished part, the quicker you're likely to arrive at a solution. You can probably get there through any of the main avenues, it'll just be tracking results as you turn the knob in one direction or the other... sorry, you probably knew all of this already.

Happy hunting!!

skidesmond
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Re: Snappy or Poppy Skis

Post by skidesmond » Wed Sep 25, 2019 11:50 am

The million dollar question with a hundred answers. Usually the pop feeling out of a turn comes from camber or the amount of pressure applied during the turn and then released. Titanal is used mostly for damping a ski and torsional rigidity. The pop feeling can also come from CF, the type of wood, thickness of the core, and the rigidity of the ski.

As a ski builder, to find out what works or what characteristics a ski has versus predicted to have, you must keep detailed notes and you should build a typical basic. Meaning, make a ski you think you’ll like. Note how it skis and pros/cons. Then make a change and do it all over again. Or use eyeball engineering like most of us do 😃.

I’ve made many sample layups (basic wood and FG, and many variations) and have compared the samples against each to get a ball park feel how a ski will perform.

Cadman
Posts: 58
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Location: Crystal Mountain, Washington

Re: Snappy or Poppy Skis

Post by Cadman » Wed Sep 25, 2019 11:19 pm

Thanks for the feedback. As much as I would like to think there is a scientific answer, everyone still reverts to the tried and true method of ‘try this and try that engineering’. Of course, there is scientific logic here but nothing beats a pile of prototypes. I see it all Winter with K2 showing up to the hill with a van full of test skis. It just costs a fortune to build all those skis if you don’t have some sort of rational plan.
I am curious as to the effects of multiple layers adding up to the same thickness of one layer. I would want to think that it would flex differently but I am not sure. Maybe it is the multiple bonding layers. I see aero space stuff done with multiple incredibly thin layers of prepeg. (like .005 thick)
We have not come up with any new material or technology for quite sometime. I will be interested to see what Checkerpoint
And wndr-alpine come up in the near future. There are a couple of interesting podcasts about them on blisterreview.com

SleepingAwake
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Re: Snappy or Poppy Skis

Post by SleepingAwake » Thu Sep 26, 2019 11:08 pm

A lot of it comes down to the shear properties of the core.

skidesmond
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Re: Snappy or Poppy Skis

Post by skidesmond » Sat Sep 28, 2019 3:50 am

There's engineering software to help figure all this out but you still need to build the ski to see how the engineering compares to the real thing. And then its still subjective to a certain degree. What seems poppy, snappy, damp to one person maybe different to another. But don't let is discourage you. Make a baseline sample layup. That's what I did. Made a number of sample layups that were 3 x 36, varied each sample with different materials, then measured how much each sample would bend and twist. Then compared each one to the other and it gave a decent idea of what worked.

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