So about two years ago, I posted an idea of laminating the composites vertically in between the core stringers. A few of you said you had always wanted to do it. Well, I finally did it with 22oz Triaxial Fiberglass. Also, since I am 16, I was eligible for signing up for the Google Science Fair. It is essentially just a national science fair that is sponsored by Google designed to find ingenuity in my generation. Well, for my project, I decided to test the effects of vertically laminated composites in alpine skis. I did a full analytic breakdown of the ski characteristics and tested it against a few other pairs of skis. I also explain the other benefits to vertical composites, like environmental. Sorry for the pedestrian language I used throughout the whole thing. I just kind of assumed that most of the judges of this competition won't really know how skis are built. Here is the link to it, so feel free to check it out: http://goo.gl/oNp3uS.
(I found it kind of ironic that the link that I was assigned for it almost spells out a ski company)
Vertically Laminated Composites
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FlamingYeti
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MontuckyMadman
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nice work, im not through it yet but you have contradictory statements here.
being as thoough I dont even know the definitions of these words I dont know what is right and what is wrong.
This is because composites are anisotropic while metal is isotropic, meaning that orientation of the material matters for composite but not metal
Furthermore, due to the isotropic nature of fiberglass and carbon fiber and the anisotropic nature of Titanal, composites have been proven more effective than metals at certain orientations.
being as thoough I dont even know the definitions of these words I dont know what is right and what is wrong.
This is because composites are anisotropic while metal is isotropic, meaning that orientation of the material matters for composite but not metal
Furthermore, due to the isotropic nature of fiberglass and carbon fiber and the anisotropic nature of Titanal, composites have been proven more effective than metals at certain orientations.
sammer wrote: I'm still a tang on top guy.
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MontuckyMadman
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There is allot to take in here and I think you did a very good job but obvious things maybe omitted.
Its tough to have a control and comparison when you may not be working with similar designs.
Obviously core thickness plays a role in torsional rigidity as well as the length of the core.
Are all those skis the same length?
Are the core thicknesses the same?
The dps have a weird curved core profile in the shovel and underfoot, not sure about the tail.
Core species type also a variable-
Are they all using the same weights of glass and you have a pure carbon ski with the dps or a hybrid?-Tough to know
The 60 degree orientation of the carbon is a strange variable for comparison.
I would assume with 2 layers of glass and carbon that ski would be STIFF, were they all compression molded with a heat cure?
Did you run the vertical composite all the way out in the core?-Does dps have metal all the way out to the tip?
Was the ski a 4 strip of metal or 2?
Its tough to have a control and comparison when you may not be working with similar designs.
Obviously core thickness plays a role in torsional rigidity as well as the length of the core.
Are all those skis the same length?
Are the core thicknesses the same?
The dps have a weird curved core profile in the shovel and underfoot, not sure about the tail.
Core species type also a variable-
Are they all using the same weights of glass and you have a pure carbon ski with the dps or a hybrid?-Tough to know
The 60 degree orientation of the carbon is a strange variable for comparison.
I would assume with 2 layers of glass and carbon that ski would be STIFF, were they all compression molded with a heat cure?
Did you run the vertical composite all the way out in the core?-Does dps have metal all the way out to the tip?
Was the ski a 4 strip of metal or 2?
sammer wrote: I'm still a tang on top guy.
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FlamingYeti
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MM,
Thanks for the questions. As for the first thing about isotropic-ness, that is actually a mistake. Totally screwed that up, but thanks for pointing it out.
I left out a lot of things because I had a certain word limit for each category. I really wanted to include more on core thickness and design of each ski, but I thought composites were more important to focus on in about 500 words as that was my primary hypothesis. All of the skis were very close to the same length. The two homemade ones were both 179. The DPS Wailer 112s were 178 as well as the Icelantics. The core thickness was the exact same on both homemade skis. The Icelantic was very similar to the homemade ones with a few minor differences of about .1-.2 mm. DPS had a few more subtle differences, starting the thin and flat area really soon on the core. The two homemade skis were the exact same shape. The Icelantic was somewhat similar with a little bit more sidecut and a narrower shovel. The DPS was also similar in terms of underfoot width, about 3 mm less narrower than the Icelantic and 5 mm narrower than the homemade ones.
As for core species, I was mainly just using the Icelantic to give a good idea of what a good, purchasable ski behaves like under these tests. I wish I could have made a pair with Titanal and a bamboo core to be directly tested against the composite ones, but we just don't have the technology.
All homemade skis were made in the same mold, under the same pressure, and same amount of time. We do not yet own a heat blanket although that is our #1 priority for this summer, so they were both pressed at about room temp. Once again, I wanted to add more info about construction but there just wasn't enough space.
DPS, like most ski companies, is unfortunately very secretive about the materials that they use. On their site, they said they use "prepreg carbon laminates." I had the chance to see the carbon they use when my dad got a super gnarly core shot on his Wailer 112's and part of the carbon started peeling off. It looked very similar to the 12K weave we bought a while ago.
Yes, the vertical composite runs all the way in the core. I'm not sure about DPS, although I am somewhat certain it goes to the tip and tail (once again, they hate disclosing any technical construction info about their skis). I am completely certain that they use two strips of metal per ski though.
I really wish I could have put all of this info into the actual project, but they just did not give us nearly enough room to give a complete writeup. Thanks though.
Thanks for the questions. As for the first thing about isotropic-ness, that is actually a mistake. Totally screwed that up, but thanks for pointing it out.
I left out a lot of things because I had a certain word limit for each category. I really wanted to include more on core thickness and design of each ski, but I thought composites were more important to focus on in about 500 words as that was my primary hypothesis. All of the skis were very close to the same length. The two homemade ones were both 179. The DPS Wailer 112s were 178 as well as the Icelantics. The core thickness was the exact same on both homemade skis. The Icelantic was very similar to the homemade ones with a few minor differences of about .1-.2 mm. DPS had a few more subtle differences, starting the thin and flat area really soon on the core. The two homemade skis were the exact same shape. The Icelantic was somewhat similar with a little bit more sidecut and a narrower shovel. The DPS was also similar in terms of underfoot width, about 3 mm less narrower than the Icelantic and 5 mm narrower than the homemade ones.
As for core species, I was mainly just using the Icelantic to give a good idea of what a good, purchasable ski behaves like under these tests. I wish I could have made a pair with Titanal and a bamboo core to be directly tested against the composite ones, but we just don't have the technology.
All homemade skis were made in the same mold, under the same pressure, and same amount of time. We do not yet own a heat blanket although that is our #1 priority for this summer, so they were both pressed at about room temp. Once again, I wanted to add more info about construction but there just wasn't enough space.
DPS, like most ski companies, is unfortunately very secretive about the materials that they use. On their site, they said they use "prepreg carbon laminates." I had the chance to see the carbon they use when my dad got a super gnarly core shot on his Wailer 112's and part of the carbon started peeling off. It looked very similar to the 12K weave we bought a while ago.
Yes, the vertical composite runs all the way in the core. I'm not sure about DPS, although I am somewhat certain it goes to the tip and tail (once again, they hate disclosing any technical construction info about their skis). I am completely certain that they use two strips of metal per ski though.
I really wish I could have put all of this info into the actual project, but they just did not give us nearly enough room to give a complete writeup. Thanks though.
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skidesmond
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Nice work and a good scientific approach. Armed with this info you can now build specific characteristics into a ski to get certain performance. Cool to see you took the experiment into making a full set of skis.
Try different species of wood like ash vs poplar vs bamboo and you'll see how using different woods can effect a ski. Add different core construction techniques and it gets really interesting.
Keep up the good work!
Try different species of wood like ash vs poplar vs bamboo and you'll see how using different woods can effect a ski. Add different core construction techniques and it gets really interesting.
Keep up the good work!
I've been toying with this idea for a while but have yet to try.
Putting 24k carbon tow between the core and the sidewalls.
Should add both longitudinal and torsional stiffness.
Guess I'm going to have to give it a go this season.
Now that I've typed it here I sure it will get a fancy name and be in next years commercial skis somewhere.
Nice work...
I couldn't imagine how stiff and heavy skis with 2 layers of 22oz triax and carbon would be.
Not sure why your results show it way softer.
UHMW sidewalls don't add any longitudinal stiffness where wood does.
More glue lines also make difference.
Wonder what weight uni Icelantic is using?
Still something doesn't add up there.
I would think 4 layers of composite would make the thing a 2x4.
sam
Putting 24k carbon tow between the core and the sidewalls.
Should add both longitudinal and torsional stiffness.
Guess I'm going to have to give it a go this season.
Now that I've typed it here I sure it will get a fancy name and be in next years commercial skis somewhere.
Nice work...
I couldn't imagine how stiff and heavy skis with 2 layers of 22oz triax and carbon would be.
Not sure why your results show it way softer.
UHMW sidewalls don't add any longitudinal stiffness where wood does.
More glue lines also make difference.
Wonder what weight uni Icelantic is using?
Still something doesn't add up there.
I would think 4 layers of composite would make the thing a 2x4.
sam
You don't even have a legit signature, nothing to reveal who you are and what you do...
Best of luck to you. (uneva)
Best of luck to you. (uneva)
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SleepingAwake
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Interesting work but unfortunately there are quite a few mistakes and you missed a little the point of vertical stringer in a core of a sandwich structure with one main direction as the case for a ski. The goal is not to improve stiffness, they are in the core to improve the shear properties of a core. If you normalize your results by the weight you should see that the vertical composites do not improve stiffness. In flexural stiffness the thickness of a sandwich structure is key, because the material in the center won’t add any stiffness at all, and the further away it is from the center, the more efficient it is. That’s why there are wood cores in skis. If it wouldn’t be that way you would better make a ski without cores and end up lighter.
And cores with vertical laminate stringers are used by a number of different brands like BD, Line, Stöckli, Faction, Icelantic, and others…
Cheers, Reto
And cores with vertical laminate stringers are used by a number of different brands like BD, Line, Stöckli, Faction, Icelantic, and others…
Cheers, Reto
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FlamingYeti
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Didn't really think about how different the homemade horizontal composite ones should have been. Strange. There must have been some problem with epoxy or hardener. We may have done uneven ratios or it might have been old. I'll look into that.
I'm not sure what weight uni Icelantic uses. Like I said in the last post, it sucks that most ski companies are so secretive about what materials they use.
SleepingAwake- I can't stress this enough: I didn't have that much space to write things! Also when I was making the experiment, I wasn't really making it for people who are experienced ski builders. I just put it on here as a resource for you guys to have fun looking at. Most people have no clue how skis are made and I was just putting it in terms the judges would understand. Yes it is true that others use stringers. I didn't. I used 1" strips of the fabric. I appreciate your input, but no need to criticize me, dude. I know how the ski building lingo works, I am just trying to put it in layman's terms. Thank you for your input though.
I'm not sure what weight uni Icelantic uses. Like I said in the last post, it sucks that most ski companies are so secretive about what materials they use.
SleepingAwake- I can't stress this enough: I didn't have that much space to write things! Also when I was making the experiment, I wasn't really making it for people who are experienced ski builders. I just put it on here as a resource for you guys to have fun looking at. Most people have no clue how skis are made and I was just putting it in terms the judges would understand. Yes it is true that others use stringers. I didn't. I used 1" strips of the fabric. I appreciate your input, but no need to criticize me, dude. I know how the ski building lingo works, I am just trying to put it in layman's terms. Thank you for your input though.
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MontuckyMadman
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sleeping I have no idea what you are talking about. Who uses vertical composites?
They use some rubber but other than dps who uses vertical composites?
That would be glass or carbon or metal or something else. Wood stringers are not in question in the hypothesis and if he used bamboo and polar then there are stringers in there depends how you look at it. WE use maple stringers for the binding area.
They use some rubber but other than dps who uses vertical composites?
That would be glass or carbon or metal or something else. Wood stringers are not in question in the hypothesis and if he used bamboo and polar then there are stringers in there depends how you look at it. WE use maple stringers for the binding area.
sammer wrote: I'm still a tang on top guy.
I remember when this topic first came up here, there was a bit of discussion about how to profile a core with metal in it.MontuckyMadman wrote:sleeping I have no idea what you are talking about. Who uses vertical composites?
They use some rubber but other than dps who uses vertical composites?
That would be glass or carbon or metal or something else. Wood stringers are not in question in the hypothesis and if he used bamboo and polar then there are stringers in there depends how you look at it. WE use maple stringers for the binding area.
I don't really remember much discussion about composites but at the time thought carbon fiber would be a good replacement for titanal.
I haven't spent too much time trying to figure out what the big guys are doing these days.
Most of them are just hyping common build ideas, and it's hard to distinguish innovation from hype. Although most of the hype is tripe.
I haven't seen any that are using vertical composites. And if they were it would be marketed as the newest big deal.
I think this idea has a fair amount of merit and yeti's research seems to prove it.
I'll give it a try next time I build, I'll build a couple identical pair but 1 will have CF between the core and sidewalls.
sam
You don't even have a legit signature, nothing to reveal who you are and what you do...
Best of luck to you. (uneva)
Best of luck to you. (uneva)
http://bcomp.ch/31-0-bCores.html they've been building cores like this for a while now.
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SleepingAwake
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Yes I was referring to the bcores. There are multiple composite stringers in there. They have a pic on their site which shows them pretty good:
@ FlamingYeti
I'm sry, I really didn't want to insult you and my criticism wasn't against you in person. In fact you have all my respect. With 16 I wouldn't been able to produce anything similar. I just wanted to point out that composite stringer in a core do make sense, but not really for the reasons you mentioned.
But keep on going!
@ FlamingYeti
I'm sry, I really didn't want to insult you and my criticism wasn't against you in person. In fact you have all my respect. With 16 I wouldn't been able to produce anything similar. I just wanted to point out that composite stringer in a core do make sense, but not really for the reasons you mentioned.
But keep on going!