Denali C75 ..41off ..Boom!

[Adam Caldwell]

Nice Job Than! There is no doubt that the technology behind the CG fin is enabling us to push the ski design into new territory.

[Adam Caldwell]

@Wish, Respectfully, PANDA. But, GREAT way to try to put it into a picture!

 

Couple things to consider;

1. This ski does not want to go downcourse during the downswing due to all the tunnel. This makes the boat move away from the skier VERY fast, so the swing rate of the rope increases. Therefore the skiers path would be much steeper into CL as a function of the swing-rate being faster.

 

2. A faster downswing rate will translate into a faster upswing after CL causing the arc of the handle moving around they pylon to actually be rounder relative to the Course/Lake.... for two reasons.

You have more energy at CL due to the increased swing speed and resulting tangential speed crossing CL.

The faster the ski comes out of angle, the less likely you are to separate from the handle prematurely due to the centripetal force. The improved connection allows you to use centripetal force to your benefit, enabling the rope to continue its swing further up on the boat - more up-course of the ball - providing for an earlier wider apex.

 

Her is why this is a difficult concept to grasp..... by getting the ski to take a narrower path relative to the BOAT, you actually end up taking an earlier AND wider path relative to the COURSE ! Sustaining a higher swing rate of the rope both before and after CL is the root cause of this phenomenon. Its a kinematic system with objects in motion traveling through space. Changing the rates of relative motion between two objects will completely change the path those objects trace through physical space.

 

In conclusion......SCIENCE.

 

Heres a slightly exaggerated correction to Wish's diagram as compared to what was already drawn out.

 

 

 

[Wish]

@adamhcaldwell Wow..I got that way wrong. Sorry you had to take so much time to unwind my misinterpretation. That's why you build amazing skis and I just ski on them, observe and learn from you guys. Thanks for the clarification ??

[Adam Caldwell]

Nothing about this sport is intuitive. Even when the answers are staring you in the face, its still hard to wrap your mind around them!

[jipster43]

Does a lot at Trophy Lakes come with a pre-order?

[Adam Caldwell]

@jipster43 - There is actually a TON of developing going on locally on Johns Island within a stones throw of the lake. So close in fact you could even see the lake!

 

[drewski32]

@adamhcaldwell where in the course does the quicker change in yaw take place? You're drawing the change occuring at a very wide point. Does the change happen closer to the second wake?

[6balls]

It seems here maybe don't mistake edge change for yaw change...unless I'm not reading right. Would it seem that the idea is that pulling edge can be maintained longer but yaw still occurring? This would seem to allow getting high on the boat early without as much mastery of doing so on the inside/turning edge early?

Adams am I full of it?

[BraceMaker]

@adamhcaldwell what's interesting is that your line.... implies a longer period of time up on the boat. Ie to achieve that location must equal achievement of a path approximating a parallel course with the pylon. So the ski must actually not be shutting down and turning as suddenly as people seem to think maybe just being good at parallel travel then turning?

[tap]

Caldwell is an animal, no doubt about it. I ran up to Trophy a few weeks back to get an early look at the c75 and sat in the boat to watch him experiment with different fin settings, it went something like... fin tweak/38off/39off, fin tweak/38off/39off, repeat, repeat, repeat... the guy didn't miss a pass. And the fin tweaks weren't exactly tweaks, more like full range of adjustment.

 

I stole one of the prototypes on my way out, I'm a few sets in at this point. And yeah, it works for mortals and hacks too! Some initial thoughts... it's a shorter ski, but you don't really notice since you run the boots so far back. The tunnel has so much lift and support, feels like plenty of ski under foot. I'm 195 lbs and riding a Large. If skis are too small they beat me up, elbows start to hurt, can't glide as needed, the c75 has none of that. It's a very easy ski to ride. Some of the very early Denali's (circa v3.1 v3.4) could be a bit twitchy if the setup was off, the c75 is smooooth. It's nutty what it lets you get away with and yet still end up with space before the next ball. After a couple fin adjustments, ran my first 35off of the year and with more space into the ball than I've ever experienced.

 

@Wish you lost me with your diagram, what I feel is much much more as Adam sketched. Very fast behind the boat, up on the boat (wide) early, and space before the ball. I've had some decent success on previous Denali models, but yeah.... not giving this one back anytime soon,,, or ever. It's just too much fun.

 

 

[eleeski]

Reality is often a long way from theory.

 

My trick ski runs the course fine because it is rolled on edge. The edge does most of the tracking whether it's a slalom or a trick ski. At the acute ski angle needed for deep shortline, the fin is not steering the ski but lifting the tail.

 

Flying in my Cessna, the rudder (fin equivalent on a ski) switches from heading (directional) control when level to altitude (attitude) control in a steep bank. Both the ski and the airplane are bodies moving through 3d fluid so the fins are doing the same thing.

 

Why the fin shape, stiffness and setting matters so much is magic. As is much of a ski's design. The Adams are wizards.

 

Eric

[Drago]

Then there's this :

https://twitter.com/zonephysics/status/1112112360624451585?s=21

 

[Wish]

@tap I may have to take a trip to Jacksonville soon. ?

[Adam Caldwell]

The old brachristochron!

[JAS]

Cycloid ski path! Bam!

 

[eleeski]

Fins suck. Wakeboards with fins make wakeboarding much more difficult. It's too easy to try and steer the board instead of finding an edge. Then, if you aren't perfect landing a trick, the fins catch and cause a hard fall.

 

Trick skis don't work at high speeds. Too much area in contact with the water. Too much lift to be able to maintain an edge at high speeds. Nothing to do with fins but everything to do with rocker, silhouette and edge shape.

 

Slalom skis are not slipping in the course. A strong edge feels nothing like a sideslide. Spray is not shooting at the boat like when doing a sideslide. And the fin is not involved in any slippage because the angle of the fin and ski.

 

In the apex of the turn, the ski is tipped almost 90 degrees. The ski design determines how it handles there. Balance the turn radius against the geometry of the speed, pull, rope length and skier skill to optimize the turn radius there. Hold the edge and angle through the wake. Run the pass!

 

Weird ski paths sounds too much like "coordinates" - remember that? Crank the turn, angle across the wake to get speed and arc a strong edged approach to the ball. Run the pass!

 

Weird sliding, yawing, skier paths or going flat will not help you run the pass. Matching the ski to your comfort level will help you run the pass.

 

Some pretty strange rationalizations are being presented to explain the Denali performance. Maybe it's just a good ski with a design that lets you comfortably work through the stresses of running the course.

 

Think 3d, like an airplane not a car on ice.

 

Eric

[AdamCord]

Honestly @eleeski I have no idea what the hell you are trying to say.

[ballsohard]

Did @eleeski do a few too many 12-ounce curls tonight?

[Adam Caldwell]

@eelski so what your saying is that wing size and shape would not affect how a plane flies. That must mean the pilot can just flap his arms and run at a comfortable speed to get the thing off the ground! ?

 

A slalom ski doesn’t slide? Please tell us more.

[ozski]

For the doubters just try the fin, its a small investment for a bloody big gain. Its a good way to sample the Denali effect. I know at least two pros that run it and probably dont want other pros finding out.

[Bruce_Butterfield]

Wow @eleeski for a while you have been making at least some sense in your postings. Looks like you are back to your normal craziness now and the world is back in balance.

[BraceMaker]

@AdamCord earlier I recall a post where you had commented that the side contours of the ski were the rocker profile of the ski. Is this something that holds true?

[AdamCord]

@BraceMaker yes this ski takes advantage of that same concept, which has a lot to do with why @adamhcaldwell has such seamless edge changes and doesn’t have to move around much at all on the ski to initiate the preturns.

[FLeboeuf]

How different is the c75 compared to the c65?

[eleeski]

OK, so I'm wrong when I question that either skiing buoy to buoy (@Wish illustration) or really late (Adam's correction) is optimal?

 

Mike Murphy can do a sideslide on a slalom ski but to think that the sidesliding of a slalom helps run the course is absurd. Edge design, tunnel design, rocker and tuning make the ski carve its path.

 

@Than_Bogan 's analysis totally neglected the 3d nature of water as a fluid. The fin is not a yaw stabilizing feature when the ski is rolled on edge. Go fly steep turns in a plane for the proof.

 

The fin modification is clever. The leading edge of the fin does most of the work. Only when the ski is actively rolling from edge to edge does the area of the fin matter. Cut a hole in that area and the ski will roll easier while retaining its other attributes. So will the old pacman fin.

 

The Denali obviously is an excellent performing ski. The result of much creative design, empirical testing, and hard detail focused work is a ski that is the right balance to run lots of buoys.

 

But attributing that to sideslip, a voodoo relationship between rocker and shape, or a hole in the fin sounds more like disinformation to keep D3 or HO from cloning the design.

 

Eric

[BraceMaker]

@eleeski - so if not for sideslip where does the force for acceleration come from?

 

IMO - the physics of this require that there be side slippage of the ski between the direction the ski is pointed and the water.

 

A world in which the ski slipped none is a world in which the ski moved forwards on the water in the direction it is pointed 100% and no slip in the vector of the boat occured (impossible unless the skier had some form of external force acting upon them - like gravity in downhill skiing, or thrust like a plane has)

 

A ski in which 100% of the motion was along the vector of the pull of the rope is slipping 100% and therefore not accelerating cross course - Trick ski in a side slide being pulled back towards the wakes? Or a disc?

 

So therefore my basic example would indicate that the differential in motion is coming from the resistance to slippage and that controlling how the ski slips and the position of the skiers mass during that slippage is your acceleration.

 

 

[BraceMaker]

^ but that the ski must still be slipping to have a differential.

 

Compelled to add that I think the vector of the rope changes dramatically and that slippage must also change dramatically - the further "up" on the boat a skier would be the more the vector of pull aligns with the vector of the ski but the closer to the wakes the more out of sync that must become.

[Adam Caldwell]

For the next trick folks, watch live footage of at @eleeski on a slalom ski!

 

[eleeski]

@BraceMaker Real world skis will have slippage. Minimal slippage is (used to be?) a desirable feature.

 

You can carve and accelerate when being towed behind a bike on skates. So attributing acceleration to slippage is flawed.

 

The pulling force vectors and the ski resistance vectors drive the acceleration.

 

There are so many factors in ski design. Some are tradeoffs. Maybe a ski will get more buoys if it rolls easier but gives up some carve stability. It's a balancing act.

 

Eric

[Drago]

Sooo, anywho: the point of my brachristochrone post was that "optimal path" may not be what @wish scribbled.

[elr]

Suddenly being tall off the second wake makes a lot more sense . . .

[richfoster]

There must be some kind of bad slippage on the Denali website. I am only getting a turquoise blank page.

[AdamCord]

For people asking about sizing.

 

We are still dialing in the weight ranges but it looks like we will have Larges first, then Mediums, then depending on demand we will do either Small or XL next. If you’re much over 200lbs you are most likely going to need an XL. Caldwell works fast but I don’t see those being available before before June.

[Wish]

@Drago ...scribbled?? I take offense.

 

I'll have you know that it took valuable time to make that misinterpretation look as good as it does. Caldwell's correction...now that is a scribble...?

[Horton]

sorry guys I was not paying attention

 

@eleeski

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

 

 

 

 

[disland]

is that a record panda count?

[Horton]

@disland it's actually just a graphical representation of infinite pandas

[Than_Bogan]

We've just witnessed the elusive dodecapanda -- so rarely seen that many did not believe it existed!

[AdamCord]

This might do a better job of illustrating the point.

 

 

 

[matthewbrown]

Adam Caldwell is a beast but I am interested in the roll of that ski. From what I’ve seen, Adam has a tendency to leave his hips and shoulders behind his feet into 1,3,5. This tendency is one that I am very familiar with as a fellow lefty it has left me in the drink several times at 1,3 or 5. However, on this ski the roll appears to be less, keeping him higher in the turn with less upper body give to the inside. This is just an observation and I don’t know if it’s a testament to the ski design, or Adam’s talent or a combo of both?

[Drago]

So a D3 does it too? ; )

[Adam Caldwell]

@Drago the point is most high level pros have figured out a technique that can make this happen. However, most of us are not high level pros, and end up on something over-stable that leads to late yaw, and too much roll too early. Sustain connection to the line is actually more important then what the ski is doing under your feet. However it’s a vicious cycle because what the ski is doing under your feet, will significantly influence you’re ability to stay connected!

 

Imagine if the ski didn’t yaw at all even through it rolled over as it heads outbound off the second wake. Sure, you’ll get the the buoy line quickly, but the handle would have been ripped out of your hands at the white water.

 

Our objective with this ski was to make it easier for the skier to accomplish a dynamic event, without even realizing what’s going on.

 

All skis will pitch roll and yaw... this one just rolls a little slower and yaws a little faster and easier.

[Adam Caldwell]

And to clear the confusion, this is what we mean when we say, “rocker matches profile”.

 

 

[AdamCord]

@Drago absolutely, any ski can do it, and all skis do to some extent. The question is, how hard is it to do this, and how good of a skier do you have to be to make it happen?

 

Our goal with this ski was to make it much much easier to change direction, so this will happen a LOT more automatically. That way a Cummins Engineer in his late 30s can strap on his ski after work and crush some 41s :D

[Alberto Soares]

That´s not a big tunnel, its a huge tunnel

[CsSkis]

@Alberto Soares - Yep! And, the proverbial light at the end of the tunnel is @adamhcaldwell and @AdamCord.

[Adam Caldwell]

@Alberto Soares

 

It’s even bigger in person. Lol

[Drago]

@adamhcaldwell @AdamCord Please notice the wink ^

What I'm getting at is: if someone goes for it and buys a Denali or a D3 or a ceramic-coated fin, or " the best you-know-whatever", and their approach and preparation and crappy rope don't change, they aren't going to ski like the 2 examples above or Bruce Dodd or Chet.

And things are not always what they seem. Should this guy straighten his back leg?v

 

[jimbrake]

@adamhcaldwell - you probably have already described, but I'm not finding, your description of the reason for the rocker matching the outline of the ski. I'm really curious about this - the reasons for it. I make surfboards, which have a nearly infinite range of combinations of rocker and profiles (not to mention bottom contours, rail shapes, lengths, widths, on and on), and am wondering about the matching of outline and rocker. I design outline for certain purposes and rocker for others. I consider how they work together, but never have tried to make them the same. Apples to oranges, I'm sure, but still I'm curious about it in the context of your skis. Thanks!

[Adam Caldwell]

@Drago little confused by your post..

 

But your right, things are not always what they seem.

 

FWIW, for me personally (right or wrong I have no idea), I try to stand tall ALL the time. It’s more obvious at longer lines when I am not dealing with such high loads as can be seen in some of the video.

 

However, regardless of the effort to stand as tall as possible (with both legs) when I watch video my legs still compress significantly. Especially at shortline passes.

 

My only explanation is that given the amount of lift produced by the tail of the ski, and the fact that the ski moves in front of you through CL in combination with your body position and pull from the boat, that it’s nearly impossible for your legs NOT to bend. They’re basically the weak link.

 

To say knee bend should be strived for as an “objective” however, is far from logical. I think @Horton had a thread going on this a while back. It’s purely a result of the ski unloading as things change directions.

 

In that 41 video from the shoreline at the start of this thread at about 12sec in, going from 4 to 5ball I remember feeling like I was pulling and standing with both legs completely extended and dead straight in attempts to get my hips back up to the handle to stay connected around the corner to the ball.

 

Buuut, watch the video and you’ll see my legs are bent like crazy for an instant before they extend again...the combination of direction change, leverage of the ski from both the water and our feet, combined with the pull from the boat, and I’m sorry, but your knees WILL bend. There’s no other option at shortline.

 

I would never coach someone to bend your knees at a 28off pass just to emulate Nate smith or any other short-line skier. The knee bend will happen on its own, and there are way more important things to be focusing on like staying connected to the handle.

 

This ski is good. But unfortunately it will not fix everything.