Ski Design - Is Wood Better?

That would be an incorrect guess.

SJ

I think they use different fertilizers too! I heard about one guy who's ac40's were made from the wrong part of the grove and the skis actually exploded while he was riding the chairlift.

serioulsy, you can't say one is inherently better, just better suited for different people.

Nobody has a monopoly on "right".

Sometimes, the difference between one person's "fact" and another's "opinion", is attitude.

I think he was referring to the magic Yak urine. Had to be!

There is perhaps no better single example of marketing and perception triumphing over engineering and objective measurement than high end loudspeakers. Audio driver design is actually an outrageously hard problem, but the response to this problem by 98% of the high end audio crowd is to wave their hands about a bunch of meaningless perceptions, much like you are doing here in this thread, as evidenced in this statement:
Right. Go back to talking about floor spikes and tube amps with the other weirdos who find facts inconvenient.

How many skis have you sectioned, by the way? When did you have injected foam (adult) K2 skis?

(I have drivers from Denmark in some of my loudspeakers btw.)

A waste of bandwidth.

As far as recent and current models, the Stockli Laser SC (GS-SL Hybrid) is synthetic core with no wood. The other Stockli race skis all have wood.

Foam is for shaving, wood is for carving.

Foam or even foam-wood mixes become lifeless so quickly. Skiing a dead ski is not fun in any circumstance.

Most of the current top 15 world cup male skiiers are on Atomic - no wood. Number 2 is Didier Cuche on Head (like Bodie) - skis cores synthetic and metal.

Rossi, Fischer, and Salomon do have wood + metal. No Volkl in racing.

I agree that it's in the construction. Wood is just one of the good, readily available and cheap materials to use if you can engineer out it's variability. Wood can have good damping and energy absorption properties - thats why it's used in skis.

How many space craft, jet aircraft and race cars use wood in their construction???

The balsa wood used in Corvettes is there for damping - see:
When someone suggested using balsa wood as the filler, "everybody laughed," said Corvette engineer Tadge Juechter. Test results, however, showed that none of the synthetic fillers matched the stiffness, light weight, and damping performance of the natural balsa-wood core, and the engineers chose the balsa design. A high-density balsa wood grown in Ecuador is used in between the glass-fiber panels.

Are you posting from a parallel universe? I assure you that (some) Atomic and Head race skis contain wood, vertically laminated and sandwiched in a light metal, just like everyone else does it. I assure you that in my universe, several WC skiers have Voelkls underfoot.

Most of them. This is why we need an antonym for Luddite. Some notable uses of wood in industry, some of which you would have seen in my earlier post if you had bothered reading the thread:

• Balsa is a common core material. Often comes adhered to fabric in narrow strips or cubes for better conformability.
• Used in many/most large transport jet aircraft as a core material for anything from fairings to floor structures.
• Ditto for ships.
• Ditto for trains.
• Balsa is a common core material in wind turbine blades, even in critical structural members such as the spar caps and shear webs.
• The initial nose cone of Trident SLBMs is Sitka Spruce. You know, those money-is-no-object SLBMs considered critical to our national defense. Capable of travelling halfway around the world to rain hell upon eight different cities.
• F1 cars all have a large wooden plank attached to the bottom as an ingenious solution to an otherwise difficult to enforce aerodynamics regulation.
• Race boats commonly use balsa cores in certain applications for all the same reasons aerospace does.
• Many monocoque race car designs over the years have used aluminum skinned balsa cored panels. I recall seeing at least one FSAE competitor do this recently.
• Many successful aircraft designs, a few designed recently, some designed nearly a century ago, use wood as a primary structural material. Some have better load fractions and cruise speeds than brand new composite airframes designed a half century later. In at least one case I recall, attempts to professionally redesign and produce aluminum versions of wood designs have resulted in increases in empty weight.

I'm sure some satellite somewhere has some wood in it, but I know next to nothing about payloads that leave earth's atmosphere, so I have no examples off the top of my head.

B-Squad

Rossi makes the smaller B-Squads with foam and metal, (less metal than the 176 and up, which are wood core and two layers of metal), and same shark tip as the whole series. The ski (06-07) is the most damp and powerful crud-buster I have skied, much more quiet in cut up heavy snow than the explosiv for example, so, structure and concept more than the simple sum of the parts, and Rossi has always been concerned with dampening in their skis (rubber layers?).

And the references to race skis as the bench mark for freeride skiing does not generally hold as the needs for both groups of skiers are not the same. Try carving turns that accelerate from loaded energy down a 50 degree confined, narrow chute of about 400 vert..catastrophic! so different structures for different types of skiing: it's all good.

Sorry Garret,

I should have said no Volkl in the top 20 WC skiers. Of course Jimmy Cochran and Kaylin Richardson (both on the US A team), and others use Volkl.

Regarding the 10 items you quote, a little research shows they are not quite what they appear to be. To qualify just two:

The initial nose cone of Trident SLBMs is Sitka Spruce. You know, those money-is-no-object SLBMs considered critical to our national defense. Capable of travelling halfway around the world to rain hell upon eight different cities.

The sikta was used in the early Trident 1 (not Trident 2) shroud designed to protect the payload during long-term storage, submarine-related environments, and early flight. It acts as its own ablative insulator and is jettisoned early. So it does not go far - certainly not halfway round the world. It was designed to be sacrificial - certainly not structural.

F1 cars all have a large wooden plank attached to the bottom as an ingenious solution to an otherwise difficult to enforce aerodynamics regulation.

A hard wooden strip (also known as a skid block) is fitted front-to-back down the middle of the underside of all F1 cars to check that they are not being run too close to the track surface, something that is apparent if the wood is excessively worn. Again a sacrificial, not part of the structure.

I was just trying to make the same point that you did earlier, that great skiis can be made with or without wood, and lousy skis can be made with or without wood.

Now that almost made me crap my pants!!! Too funny

Yes. Wood is better.

I'd maybe think differently if I knew who Johnny Cochrane Diddler Douche and Bill Richardson were, but thankfully I remain blissfully ignorant.

Im pretty sure Head RD skis have a wood core. under all that techno gadgetry.

The initial nose cone...

You miss the point. Protecting a light rocket from the Q imposed by launching it through water is effectively done with an inexpensive, widely available material. Despite the closest thing to an unlimited budget that there is, the weapon designers choose wood. They could have spent your tax dollars on something more expensive to discard in an ocean someplace after a 100 foot ride...but they didn't.

Again a sacrificial, not part of the structure.

Yes, I'm aware that it is sacrificial. That is the entire point of the application. If you sacrifice too much of it, you get a DQ. I'm not aware of a more appropriate material for the task...again, this is a sport where budgets are nearly unlimited and some teams do utterly pointless things like make custom carbon fiber master cylinder reservoirs (while Ferrari's are plastic, available in a catalog, and affixed with zipties.) I didn't google this, I spouted a few applications off the top of my head.

I don't know how strong your google-fu is, but I suspect you determined that the structural applications I mentioned are extant and widepsread.
I just didn't want to give a free pass for naive assumptions about super-magic materials. Humans have forgotten more about materials than they know. The quote from the GM guy is demonstrated corporate ignorance. It is always wise to remember that what is popular today has less to do with what works best than...what is popular today. This applies strongly to skis and wood.

Most of my skis have wood cores btw. This reflects in part my preferences, but moreso the preferences of the gaping masses.

And yes Richie, I'm sure most real Head race skis contain vertically laminated wood cores sandwiched in a low density metal...just like most real race skis from everyone else. Broken skis are everywhere...put a saw to good use and see for yourself. Atomic has actually made some of the more interesting combos I've seen, with entire traditional (wood/metal) constructions laid into a cap with foam for certain Beta race skis.

In a free market, the fact that you see both wood and composites used at different levels of skiing means essentially that there is no clear winner. Both materials have their advantages.

I think the question of better has a lot of assumptions implied in there and that unpacking those might help. First off better for who? In many ways I think that you see that the designer is picking the materials based not on what is better for the skier but based on what is easier to manufacture at the scales needed.

Wood, works great for small scale production. But if you are making 1000 skis and want to be all be the same, then wood will probably be pretty involved in terms of sourcing the wood at the volumes you need, then laminating it for uniformity, then doing a QA/QC. Where as synthetics you can build as much as you want and engineer a lot of the variability out of the materials. Synthetics, become cost effective for large scale productions where higher upfront costs is distributed over 1000s of units. At different scales you have different problems and the different materials are better at different scales.

I don't know if wood is intrinsically a better performing materials, but perhaps it allows greater flexibility for use in custom hand made skis in small batches for top level skiers.

Excellent analysis as per usual from tromano. And rereading it, it may appear the saw comment was hyperbole. Seriously, sawing ski equipment apart is instructive and fun. Boots are fun to slice as well.

Garrett: Have you tried decaf?

Some woods are better.

Not all woods are created equally.

There are three characteristics for any core material that will determine how a ski feels and it's longevity.

Bending Strength. This is the force required to bend a material. A high bending strength requires the ski to be powered for optimal performance.

Elasticity. The more elasticity a material possesses the longer it will maintain its snap before going ‘dead‘. High elastic cores will be able to endure agressive flex then return to its original shape more often than skis made of other materials.

Crush strength. Crushing strength refers to the material‘s ability to absorb impacts before being deformed. Higher crushing strength equals increased ability to sustain shocks and impacts.



Ask your favorite ski tech what is in a particular ski? All woods are not the same.

Garrett

Thanks for the input, the pointers and comments.

I think we are coalescing around the what Tromano is saying.

I don't know if wood is intrinsically a better performing materials, but perhaps it allows greater flexibility for use in custom hand made skis in small batches for top level skiers.

And wood sure looks nicer when it's growing than foam No-one ever thought a petrochem plant looked better than a forest.

Interesting how people who dislike synthetic-core skis refer them as "foam", and those in favor prefer "composite".

I guess it doesn't sound gnar to be ripping on "foam".

Connotation is everything.

No, when talking about the non-wood core skis, there are skis that are in fact foam. Then there are skis that are laminated composite (non wood). Then, from what I understand there are combinations of the two...which I think are still referred to as foam skis.

If it ain't wood, it's foam.

Sounds better.

From DPS website:

The Skinny on Ski Cores

Posted October 13, 2008 2:41 AM by DPS News Agency

There is a tremendous mystique about the core in a ski. And even more mystique about wood as a core material. Some of this is historical, some based on science, and some based on experience.
Skis started out as just wood so there is history and tradition associated with wood. When aerospace materials and sandwich construction came on the scene the new structural materials (primarily aluminum and then fiberglass) were just glued to the top and bottom of the wood already there. The wood went from being the structural layers of the ski to just being the core. The wood core became a support structure for the new structural materials. Dramatic performance and durability improvements followed.
Many ski companies still promote wood as the essence of their skis. Foams were developed for core materials but it took quite a while to get good performance foams that were durable and strong enough for the task. Early foams, and the injection ski technology still used today for very low-end skis, gave foam as a total family a very bad reputation. That technology challenge has been overcome with high performance foams and well executed designs.
The core is part of a whole structure. In its simplest form the core keeps the top and bottom structural layers in their correct position and transfers loads or stresses between them when the ski bends, twists and gets hit with impact loads. So when is the core material important and when is it less so? In a fiberglass ski the stiffness (or modulus) of wood is around 50% of fiberglass. So wood has quite an influence on a fiberglass/wood core ski. So when comparing fiberglass skis the use of wood core is a significant part of the overall feel of the ski.
In a carbon ski, the carbon is about 10 times the stiffness or modulus of wood, depending on the fiber lay-up orientation. The net effect is that the core material has a lesser effect on the overall performance of a high modulus ski made out of aluminum, steel, or carbon.
All foams, unless they reach the density or weight of wood have a fraction of the stiffness or modulus of wood. But since foam cores are so much softer than wood the difference in a fiberglass ski is really pronounced with wood being so close to fiberglass. So, fiberglass skis made with wood cores frequently perform better than foam core counterparts. But for the aluminum, steel, and carbon skis a switch to foam is not as significant because the foam and wood core properties are so much lower than the structural component. Hence the actual core material in aluminum, steel, and carbon skis does not dominate the ski performance as much as it does in a fiberglass ski.
The different mechanical properties of cores can be adjusted for in the overall design. Strength and durability becomes the big issue with foam. Foam is dramatically lower strength than wood. So foams are reinforced or made with very high density to get their strength and durability high enough. Or else they just don't last. Foam impact strength is also much lower than wood.
Some very light foams are so weak and soft that they need ribs to reinforce them, especially at the cure temperatures of a ski. A good series of vertical ribs can even negate the need for a foam or wood core at all. But it has to be well executed. Less than successful efforts have been made to create ribs structures in previous iterations of carbon skis. The ribs are folded with air pockets and lack adequate pressure to create a solid rib. The resulting core structure is compromised making the ski weaker and less durable than using a higher performance core material. Those vertical ribs also add weight, which could be traded off for a higher density and therefore stronger core, whether it be foam or wood.
Sidewall construction skis usually use wood as the core material. The wood core can withstand the high pressures of molding to create a very solid laminate. Using a foam core usually requires a cap ski design to prevent the molding pressures from crushing the core. Foam core in a sandwich ski, without a special mold design, cannot withstand the high temperature and pressure of aerospace carbon prepreg.
DPS uses a lightweight wood core to achieve the best combination of ski performance, excellent laminate properties, and field durability. Wood cores in our skis are field tested with finely tuned flex designs to provide the best in both performance and feel.

I guess the obvious way to settle this is to get a hold of the old "foam" ski and the new wood ski and do a head to head, ski off.

For the record, all the skis in my active quiver (Scott P4, head im103m, praxis pow, K2 PE) are all wood core skis. But I don't think composite skis suck.

Some skis just suck but it seems the crappy composite skis are seen as generally representative while crappy wood skis are seen as the exception to the rule. But... quite a few of the supposedly crappy composite skis that have been discussed in this thread used to be well reviewed and highly regarded on this forum at the time they came out. I will leave it to curious parties to check the arcives. Search for RX8, Metron B5, Contact 11, etc... And lets not forget before the gotama for 3 years the Solly foam core blue noodle was the most popular pow ski that you could find. Obviously the technology has moved on, but this sort of revisionist history seems pretty strange.

Okay lets clear things up here, because I think a few of us are talking about different things.

Composite: fiberglass and carbon fiber primarily
Foam: primarily foam with a composite shell/cap
Wood: primarily wood with a composite shell/top/cap

This sound okay with everyone?

If so I dont think there is really any strong argument against composite skis, the arguments are towards whats known as foam skis, which up until recently were also known as econo skis, cheap skis, or dept. store skis.

Nope. Lots of composites do not have carbon, lots of foams do not have caps/shells, let alone carbon, and cannot make sense of of the last (wood), which seems to say again that the non-core part of the ski must include carbon. Face it, this stuff defies simple taxonomies.

Which is why I keep it simple.

Chicks dig wood, and so do I (underfoot).