2 technical issues

Various topics, technical questions, announcements, events, resorts, ...

Moderators: fivat, rilliet, Arnaud, nils

User avatar
István
Rank 5
Rank 5
Posts: 899
Joined: Monday 29 September 2003, 13:04
Location: Budapest, Hungary

2 technical issues

Post by István » Friday 16 April 2004, 15:29

Guys,

I'd liket to raise 2 technical issues (I have my own opinions about them, but would like to test it against yours):

DAMPENING: what is it, what is it good for, pros and cons.

SIDECUT SHAPE: radius, elliptical, other types, pros and cons.

Cheers,

István

ps.: Definetely would like to see the Swoard team's opinion which I guess manifested in the Swoard

User avatar
skywalker
Rank 5
Rank 5
Posts: 815
Joined: Saturday 3 August 2002, 11:24
Location: Fribourg (CH)

Two answers...

Post by skywalker » Friday 16 April 2004, 15:59

Hi istvan,

I'll try my best ;))

First, dampening is more easy. It's the ability to absorb vibrations. So a snowboard is a spring-dampener-system, which would chatter around uncontrollably without dampening. The harder a board is, the more dampening is theoretically needed, but most of the very hard boards don't have enough dampening. This is why the can do great jump turns but lose edge-grip easyly. I'm not sure, if there can be too much dampening in a board, but i guess it would be ultra-stable but no more junpy. The hysteresis of materials is a good parameter for the dampening behaviour of materials, so this is one way to absorb vibration. Another effective dampener is mass, so a good distribution of it will improve dampening, too. Did I get your issue???

Sidecut is a issue, I have discussed with mates in the past very much. It's not at all that easy, because even a radial sidecut in changed by the torsio of the board. Today I believe (This might be totally different next year) that a radial sidecut gives your board a more snappy behaviour. This is, because the radius is narrower at the nose, than it is with a parabolic shape. So at the beginning of a turn, the nose of a board with radial sidecut will "pull" the board into the turn. A board with a parabolic sidecut can be steered more precisely in slight turns and the initalizing of trns is a way of softer. Until here, I'm pretty sure about the thesises

Now the part of my thoughts is coming, which I still think about. First: Because of the mentioned torsion and the rather small differences in outlines between boards with parabolic and radial sidecut, they are very similar in extremecarving turns. So a torsional slightly softer board with radial sidecut might behave the same way like a slightly harder with parabolic shape. This is beause the resulting curve on the snow surface can be exactly the same. And now there comes a point, the Swoard-crew will completely disagree. I believe, that a board with a parabolic sidecut can go every radius you want it to go just by higher angulation between the board and the surface and more pressure provided by your legs. I describe it as turn radius directly proportional to steering effort. A board with a radial sidecut tends to go it's own turn radius, not only one, but if you don't correct, maybe five different turn radii. This is more like a response in steps, than in a straight line. These are suggestions, not much more.

I have to admit, that it is naerly impossible to feel these effects without a doubt, because as mentioned the stiffness of a board and even its distribution effects the board behaviour, too. So it's nearly impossible to compare boards an to say, which one of the difference you feel depends on a special difference between the tested boards.

This is only my humble opinion, so please tell me, what you think ;)

User avatar
István
Rank 5
Rank 5
Posts: 899
Joined: Monday 29 September 2003, 13:04
Location: Budapest, Hungary

Post by István » Monday 19 April 2004, 15:05

Many 'views' but only one answer so far. C'mon guys....

István

User avatar
skywalker
Rank 5
Rank 5
Posts: 815
Joined: Saturday 3 August 2002, 11:24
Location: Fribourg (CH)

Hey Istvàn

Post by skywalker » Monday 19 April 2004, 15:09

seems that I totally shocked everybody with my answer ;)
Hey, tell me, what you think about!

User avatar
pokkis
Rank 5
Rank 5
Posts: 1804
Joined: Monday 1 April 2002, 19:46
Location: Finland

Post by pokkis » Monday 19 April 2004, 15:31

So have any of you done maths and calculated dimension differences between these sidecut options ? What kind measurements we are talking about here, according my cut feeling they are very minimal ones, but being too lazy to do maths :lol:

User avatar
bowen
Rank 5
Rank 5
Posts: 111
Joined: Sunday 28 March 2004, 18:20
Location: Oberbayern

Post by bowen » Monday 19 April 2004, 15:41

very intresting,

and with every topic i read here, i get farer an farer from the desicion wath stuff i should by for next season, to have a eqipment wich makes possible to ride al tarrain and also can do ec :(

verry confuse greetings from bavaria

bowen :dogeyes:
...sunny days ar the best!

User avatar
skywalker
Rank 5
Rank 5
Posts: 815
Joined: Saturday 3 August 2002, 11:24
Location: Fribourg (CH)

Hi Pokkis ;))

Post by skywalker » Monday 19 April 2004, 16:14

Well, I did some calculation a few years ago. But this was mor about which radii of the parabola would be needed to effectively improve the behavior of a given radial sidecut. Well, the differences were extremely small, but tendencies could be seen...

But my answer was completely theoretical on one hand, which is: To achieve a round contact path with a bent board, you need a parabolic sidecut or more torsion. Maybe *LOL*. Problem with this is: I did not do any accurate alaysis about this, only some qualitative. On the other hand I was talking about what I thought to feel when comparing boards with radial and parabolic sidecut. Here the main problem might be to know, on what you can rely or not. Is it possible, that I feel the difference in riding between two board differing only in parts of millimeters???? I don't know, but why not??

What Du you think?

User avatar
István
Rank 5
Rank 5
Posts: 899
Joined: Monday 29 September 2003, 13:04
Location: Budapest, Hungary

Technical characteristics

Post by István » Monday 19 April 2004, 18:13

Guys, I've read articles here on length, stiffnes, radius, heel-lift, angles, etc. All technical and all difficult to measure the effect of.

Now I've raised 2 other issues and you say they are too technical and come down to math, so are not worth to discuss.

István

User avatar
Tim
Rank 3
Rank 3
Posts: 26
Joined: Friday 22 March 2002, 22:09
Location: Netherlands

differences

Post by Tim » Thursday 13 May 2004, 20:40

It's been a while since I've been here...

Anyway, I once did the math for the difference between a radial and a parabolic sidecut. The differences are VERY small, less than 0.02mm unless you get extreme board dimensions (very long board with small radius). I don't think anybody sharpens their edges accurately enough to be sure which sidecut he's riding.

User avatar
István
Rank 5
Rank 5
Posts: 899
Joined: Monday 29 September 2003, 13:04
Location: Budapest, Hungary

Sidecut

Post by István » Friday 14 May 2004, 17:54

Hey Tim,

The first answer really related to the question!!! Took a bit of time :-) but a really good point.

Cheers,

István

ps.: Not to mention that this is the first reply to English topics in the last 10 days..... what's wrong with you, no Swoard no chat?

User avatar
nils
Swoard founder
Swoard founder
Posts: 3043
Joined: Friday 22 March 2002, 19:22
Location: Lyon, France - Swoard team
Contact:

hehe :)

Post by nils » Friday 14 May 2004, 18:16

it means no snow no chat!!
people are scanning the forum, but aren't feeling motivated to post :)
its summer coming it seems!

n.

User avatar
István
Rank 5
Rank 5
Posts: 899
Joined: Monday 29 September 2003, 13:04
Location: Budapest, Hungary

Summertime

Post by István » Saturday 15 May 2004, 18:57

Well, that is an option... in this case we could come up with topics like:

- how to store equipment in summertime (mine is under the bed)

- how to prepare used equipment (not much to do with mine, fortunately)

- what to buy for the next season (already did, but can't tell here...)

- what to do instead of EC (As for myself I ride my motorbike. Very similar feeling to EC.... hurts a bit more when you miss a curve...and much more expensive to buy all the stuff you need.)

- list of open glaciers nearby (anyone knows if Sölden is open or not?)

Cheers,

István

User avatar
nils
Swoard founder
Swoard founder
Posts: 3043
Joined: Friday 22 March 2002, 19:22
Location: Lyon, France - Swoard team
Contact:

Istvan

Post by nils » Sunday 16 May 2004, 1:00

Do not store the boards flat, it will ruin camber! At least put them vertically on the side, ideally on the tail!
Soelden opens june 29 I think, and les deux alpes opens june 19th!!

Nils

User avatar
István
Rank 5
Rank 5
Posts: 899
Joined: Monday 29 September 2003, 13:04
Location: Budapest, Hungary

Storage

Post by István » Monday 17 May 2004, 9:37

Thanks for the hint!

István

User avatar
István
Rank 5
Rank 5
Posts: 899
Joined: Monday 29 September 2003, 13:04
Location: Budapest, Hungary

Storing the board

Post by István » Thursday 20 May 2004, 9:12

Nils,

I'd like to get back on the storing issue for a sentence. Not easy to find a good place for the board to store vertically if you live in a flat and you do not have a garage.

What about laying it on the ground, up-side-down, propped-up at the nose and tail, so that the waist slightly touches the ground. In that case I guess the camber will not die.

What's your view on this?

Cheers,

István

Locked