DPS S.S.- the next level

[enzo3366]

The fact that there was almost no vibration dampening was the main reason why i hated the pure carbons when I demo'd them. Definitely want to give these a try to see how they ski!

[fouldsys]

i was planning on getting 120s next season but i might need to make room for some rp112s with the special sauce as well now.

[Shorty_J]

I am officially saving.

[arild]

Cannot afford Dynafit,
Want Dynafit,
Cannot afford Lotus 120s,
Want Lotus 120s.

Holy crap, this sounds good.

[stone88]

Saving for 138's! Hoping for return of pinstripes for next season also!

[lobstahmeatwad]

OMG!

[dynodonkeyaltabird]

i hated the pure carbons

YOU CRAZY!!!!

[gisforgaper]

Caught the DPS demo day at KW yesterday. Skied the 185 Wailer 95 Hybrid and the 190 Lotus 120 - I think it was the 08/09. Interesting feel to both skis.

Wailer 95 -quick edge to edge and really lively. Saturday was a hardpack day, so I tore around groomers and through the trees. I really liked the ski in the trees. It was a bit more responsing than my Mantras. Running down the groomers though I just couldn't get used to them. At high speed every feature in the snow caused a bit more reach than I expected. Definetly felt the Mantras were more solid at speed.

Lotus 120 - Saturday did not have the conditions to evaluate these properly. That said, I ran a couple laps out to the Palisades and found some snow worth skiing - 24" of heavy 4 day old snow, and 1-2" of breakable crust on top of 24" of soft. Compared with my 190 Bibbys, the skis were really surfy and floaty. I got a few turns in heavy pow and was really surprised by the feel - I didn't know what a slarve was until I tried them. On the crust, they weren't very stable for me. With any speed the skis stayed on top, but the tips flapped a bit and just got pushed around. As soon as I returned the Lotuses I ran back to the same spot with my Bibbys and felt the crusty stuff was much more manageable.

The reason I posted this here was that I think a bit of metal would have really helped in both cases. With some additional dampness, the 95 could be my all mountain replacement in 2011. The 120s were pretty great on thier own, but could be more versatile with the metal.

[rip]

This looks awesome.

So how do we go about sending our old pairs in for retrofitting?

[DictatorShooter]

Sweet! After enjoying several powder mornings and cursing several chopped up afternoons on the 138's lately, my feet thank you in advance.

[khyber.pass]

Mmm, this particular innovation will be a game-changer. Cut-up, crust & mank has always been the trade off with carbon. The SS with the RP112 dimensions is going to make a very desirable plank in PNW + BC conditions.

[SiSt]

Could somebody please enlighten me on the theory of how and why metal layers dampen skis? Just a basic rundown of the normal "layered above and below the core" race construction, and how that transfers into the "S.S."-version of it.

I´ve had this discussion with a couple of engineers with experience in composites, and the only actual conclusion we´ve come to is that the added weight is what really helps, changing the resonant frequency of the ski, and making it deflect less due to the added mass.

One of the said engineers is going to do some FEA on this once he finds the time, but if anyone has an answer already, please let me know.

[XtrPickels]

I believe pechelman wrote something up in regard to resonant frequency and the legend pro.

[marshalolson]

Could somebody please enlighten me on the theory of how and why metal layers dampen skis? Just a basic rundown of the normal "layered above and below the core" race construction, and how that transfers into the "S.S."-version of it.

super over simplification, but here is my .02

imagine a tuning fork.

in a fiberglass ski, there is nothing to resonate, the ski is pure dampening. to make the ski livilier, manufacturers add higher modulus woods than in below. the wood controls the ride of the ski. the f/g is there to tune the wood's feel.

a metal laminate ski has a tuning fork top and bottom. the 2 arms of the tuning fork are tied together by tightly blocked wood core laminates. this adds significant weight in the resin bonding the wood together. thus the ski is damp. this makes the ski more reactive and lively than a traditional F/G ski. it also makes the ski much heavier (in general). the metal and amount of vertical laminates dominate over the type of wood used here.

in a true pre-preg carbon ski, the carbon layers act as the harmonic layer. wet layup "carbon" skis are much more similar to f/g skis, other than being a little lighter. since the carbon is so much stiffer than metal or F/G, the manufacturer specs a lighter, less dense, and thinner wood core. the addition of SS to this laminate is the equivalent to bridging the 2 arms of the tuning fork with you finger. it provides a "sink" to the resonance. in addition, the orientation of the SS layers serve as an "i-beam" so that they stiffen and dampen the ski in the manner it needs it (longitudinal) vs. a traditional metal laminate that bends very easily in the longitudinal direction.

hopefully that makes sense?

i am sure stephan (dps) can write a much more elegant response than this ^^^

[Mustonen]

^^^ I follow most of that, other than the apples to apples comparison of carbon fiber and fiberglass. Doesn't the carbon fiber Add pop/liveliness? To adopt your analogy, in my head I'd thought of the metal strips as being the tuning fork top and bottom, so to speak.... (edit: maybe not, but I'm still having a hard time lining up all the elements of the analogy in a way that makes sense).

Anyhow, sounds cool, and those 112s are way up there on the "want" list.

[marshalolson]

^^^ I follow most of that, other than the apples to apples comparison of carbon fiber and fiberglass. Doesn't the carbon fiber Add pop/liveliness?

that is because carbon fiber is higher modulus. significantly stiffer and more springy. think of ss as a way to tune the spring (carbon)

To adopt your analogy, in my head I'd thought of the metal strips as being the tuning fork top and bottom, so to speak.... (edit: maybe not, but I'm still having a hard time lining up all the elements of the analogy in a way that makes sense).

the top layer and bottom layer of the ski, regardless of construction are the tuning fork legs.

in a glass ski, the tuning fork legs are not metal, its like hitting a block of wood. dead.

in a metal ski, the super tight wood core layers (and lots of resin) dampen the tuning fork legs. both the solid sheet of metal and the additional resin in the laminates add significant weight. but the ski is smooth and relatively reactive. you are adding significant weight to achieve the dampening.

in a ss construction ski, the metal ribs tie the carbon tuning fork legs together, reducing vibration and providing a sink for the waves to follow. this serves to create the light, reactive and poppy ride of a carbon ski, with a smoother more "metal" ride quality. without adding weight.

more clear?

[Mustonen]

that is because carbon fiber is higher modulus. significantly stiffer and more springy. think of ss as a way to tune the spring (carbon)



the top layer and bottom layer of the ski, regardless of construction are the tuning fork legs.

in a glass ski, the tuning fork legs are not metal, its like hitting a block of wood. dead.

in a metal ski, the super tight wood core layers (and lots of resin) dampen the tuning fork legs. both the solid sheet of metal and the additional resin in the laminates add significant weight. but the ski is smooth and relatively reactive. you are adding significant weight to achieve the dampening.

in a ss construction ski, the metal ribs tie the carbon tuning fork legs together, reducing vibration and providing a sink for the waves to follow. this serves to create the light, reactive and poppy ride of a carbon ski, with a smoother more "metal" ride quality. without adding weight.

more clear?

Brilliant.

So, how did the 112rp ride?

[marshalolson]

long story short, it shreds. super fun ski. it rails on groomed, which i was not really expecting.

[Milkshakes]

long story short, it shreds. super fun ski. it rails on groomed, which i was not really expecting.

Have you been on both the pure and the hybrid 112rp? What is the difference in ride feel, etc..?

[Milkshakes]

I just saw a post below on Hybrid vs Pure general comparison. Got most of the relevant info, but still wondering if you have ridden both constructions in the 112rp. thx..

[marshalolson]

i have not skied the hybrid, only the pure thus far.

[SiSt]

I´m very sorry, but I still don´t get it.

How come metal (titanal normally) absorb the energy and dampen the rebound? Fair enough, it has a lower modulus than carbon (but higher than wood), but it will not lose much energy when acting as a spring. It´s isotropic, which means it will stiffen a ski in all directions equally (as opposed to a fiber) when used in a sheet above and below the core.

As for using it to tie the carbon on both sides of the core together in the S.S., this seems pretty optimistic, as it is only bonded to the carbon on the (very thin) edges of the metal, flush with the wood. From the images at the start of the thread, only about 1/50th of the surface area in contact with the carbon layers is metal, the rest is wood, so the bonding strength of the metal-carbon would have to be exceptionally high when compared to the wood-carbon for it to have an effect in this manner. (not sure about this last statement, but it seems logical)

I can see that a metal sheet laminated vertically into the core would help in making a stiffer core at the same relative thickness and that the orientation of the metal means you´re using it in a more efficient way, but I still fail to understand how it can make the ski more damp.

[marshalolson]

i think it might be time for dps to jump in and bust the engineering action.

the orientation of metal, if it has different thicknesses, is controlling on its behavior, and is not isotropic.

but:

DAMP should be defined. i feel like its a voodoo word that people use, but cannot define or know what it means.

"damping" means to reduce the amplitude of oscillations....

Overdamped: The system returns to equilibrium without oscillating.
Critically damped: The system returns to equilibrium as quickly as possible without oscillating.
Underdamped: The system oscillates with the amplitude gradually decreasing to zero.

the goal of ss is to achieve critical dampening. maximize snap and life but to have no further oscillations.

[SiSt]

I´m all ears.

Hopefully its possible to explain well without going into too much math.

[Daywalker]

'shral... since you're cool enough to have skied the Pure w/ S.S., would you say your comments in the Pure vs. Hybrid debate are still accurate or are the Pures now boosted up to be in line with the hybrids in skiing chopped up resort type snow.