Physics debate

This is the World Famous TelemarkTalk / TelemarkTips Forum, by far the most dynamic telemark and backcountry skiing discussion board on the world wide web. We have fun here, come on in and be a part of it.
User avatar
lowangle al
Posts: 2755
Joined: Sat Jan 11, 2014 3:36 pm
Location: Pocono Mts / Chugach Mts
Ski style: BC with focus on downhill perfection
Favorite Skis: powder skis
Favorite boots: Scarpa T4
Occupation: Retired cement mason. Current job is to take my recreation as serious as I did my past employment.

Re: Physics debate

Post by lowangle al » Thu Jan 05, 2023 7:53 pm

That's what I noticed, that's your niche. You were hooked from the start.

User avatar
Musk Ox
Posts: 520
Joined: Sat Jan 19, 2019 7:53 am
Location: North
Ski style: Bad
Favorite Skis: I am a circumpolar mammal
Favorite boots: Hooves
Occupation: Eating lichen, walking about

Re: Physics debate

Post by Musk Ox » Fri Jan 06, 2023 10:26 am

lowangle al wrote:
Thu Jan 05, 2023 4:21 pm
Musk Ox wrote:
Thu Jan 05, 2023 3:58 pm
Hi, I'm here now. I took a few days offline over the New Year to hammer my knuckles with an aluminium meat tenderiser hammer (personal science project).

This thread looks really interesting and I would like to contribute, could someone recap the principal arguments
To fully understand this thread you need to go to the "Explore vs. 3 pin w/cabls thread" and read through it.
An informative read indeed.

As I suspected, I have nothing to contribute after all.



User avatar
DG99
Posts: 247
Joined: Sun Feb 20, 2022 3:39 pm
Location: Oregon

Re: Physics debate

Post by DG99 » Mon Jan 09, 2023 12:53 am

Wow, late to the party, but I really don’t get this.

Of course, torque forward it applies pressure to the front of the ski.



User avatar
ochotona_ak
Posts: 14
Joined: Fri Feb 11, 2022 2:42 am

Re: Physics debate

Post by ochotona_ak » Mon Jan 09, 2023 1:18 am

bauerb wrote:
Thu Jan 05, 2023 6:23 pm
. but to your point, I competed( and still do) in lots of forms of skiing, just not tele( mainly because I've never heard of a tele race nearby...if there was one nearby, I would have no choice but to enter).
There's weekly tele races at Snowbowl in Missoula - just sayin'



User avatar
tkarhu
Posts: 321
Joined: Thu Jan 13, 2022 11:58 am
Location: Finland
Ski style: XCD | Nordic ice skating | XC | BC-XC
Favorite Skis: Gamme | Falketind Xplore | Atomic RC-10
Favorite boots: Alfa Guard | boots that fit

Re: Physics debate

Post by tkarhu » Mon Jan 09, 2023 2:45 am

DG99 wrote:
Mon Jan 09, 2023 12:53 am
Wow, late to the party, but I really don’t get this.

Of course, torque forward it applies pressure to the front of the ski.
I wonder too, how can you pressure the front of a ski with free heel bindings? Pushing front ski downwards, there seems to be only a free rotating axle in free heel bindings, how can you push with that.

You can pressure the heel by pressing your heel because then you have your front attachment to push against. There you have two attachment points. But in the front I feel I can only pressure the top of a ski, for example when I need to lift snow. There you have also contact at both toes and heel.



User avatar
tkarhu
Posts: 321
Joined: Thu Jan 13, 2022 11:58 am
Location: Finland
Ski style: XCD | Nordic ice skating | XC | BC-XC
Favorite Skis: Gamme | Falketind Xplore | Atomic RC-10
Favorite boots: Alfa Guard | boots that fit

Re: Physics debate

Post by tkarhu » Mon Jan 09, 2023 2:53 am

DG99 wrote:
Mon Jan 09, 2023 12:53 am
Wow, late to the party, but I really don’t get this.

Of course, torque forward it applies pressure to the front of the ski.
I wonder too, how can you pressure the front of a ski with free heel bindings? Pushing front ski downwards, there seems to be only a free rotating axle in free heel bindings, how can you push with that.

You can pressure a rear ski by pressing your heel because then you have your front attachment to push against. There you have two attachment points. But in the front I feel I can only pressure the top of a ski, for example when I need to lift snow. There you have also contact at both toes and heel.

EDIT: I guess NNN-BC flexors and NN cables allow to pressure ski tip. Was it @Verskis who measured this. That lets you pressure rear ski tip to some extent, was it so.



User avatar
tkarhu
Posts: 321
Joined: Thu Jan 13, 2022 11:58 am
Location: Finland
Ski style: XCD | Nordic ice skating | XC | BC-XC
Favorite Skis: Gamme | Falketind Xplore | Atomic RC-10
Favorite boots: Alfa Guard | boots that fit

Re: Physics debate

Post by tkarhu » Mon Jan 09, 2023 6:03 am

Verskis wrote:
Tue Jan 03, 2023 3:19 am
You can make an experimental test about the tip pressure: take one ski (with a binding), one boot, two scales, and some Voile straps.

First put the ski on the scales, and tension the binding springs with the Voile straps like on the bottom picture. You will see roughly 50/50 split of the weight on the scales. Tensioning the Voile strap (and thus tensioning the binding springs) more does not affect the readings on the scales at all. This is your closed system.
Do I interpret correctly that a stiffer NNN-BC flexor would probably not increase tip pressure?



User avatar
lowangle al
Posts: 2755
Joined: Sat Jan 11, 2014 3:36 pm
Location: Pocono Mts / Chugach Mts
Ski style: BC with focus on downhill perfection
Favorite Skis: powder skis
Favorite boots: Scarpa T4
Occupation: Retired cement mason. Current job is to take my recreation as serious as I did my past employment.

Re: Physics debate

Post by lowangle al » Mon Jan 09, 2023 7:26 am

tkarhu wrote:
Mon Jan 09, 2023 2:45 am
DG99 wrote:
Mon Jan 09, 2023 12:53 am
Wow, late to the party, but I really don’t get this.

Of course, torque forward it applies pressure to the front of the ski.
I wonder too, how can you pressure the front of a ski with free heel bindings? Pushing front ski downwards, there seems to be only a free rotating axle in free heel bindings, how can you push with that.

You can pressure the heel by pressing your heel because then you have your front attachment to push against. There you have two attachment points. But in the front I feel I can only pressure the top of a ski, for example when I need to lift snow. There you have also contact at both toes and heel.
You can get more pressure towards the tip of the lead ski by putting more weight on the front of your foot, while keeping a flat foot on the ski. The fulcrum would be the boot center on the lead ski.

On the trailing ski, with only the ball of your foot on the ski you need some resistance from the binding to get it. You get it from the bail on a three pin, the cable on a cable binding or the bumper/flexor on explore or nnn.



User avatar
GrimSurfer
Posts: 638
Joined: Sun Dec 11, 2022 11:56 am
Ski style: Nordic Backcountry
Favorite Skis: Yes
Favorite boots: Uh huh

Re: Physics debate

Post by GrimSurfer » Mon Jan 09, 2023 9:38 am

The good news is that folks are starting to say “towards the tip” and not “on the tip” any more.

The mind blowing thing is that the more that skier mass moves forward, the more the front half of the ski flattens. That flattening moves from the front of the ski towards the middle of the ski. This effect is more pronounced on a soft, single cambered ski.
We dreamed of riding waves of air, water, snow, and energy for centuries. When the conditions were right, the things we needed to achieve this came into being. Every idea man has ever had up to that point about time and space were changed. And it keeps on changing whenever we dream. Bio mechanical jazz, man.



User avatar
lowangle al
Posts: 2755
Joined: Sat Jan 11, 2014 3:36 pm
Location: Pocono Mts / Chugach Mts
Ski style: BC with focus on downhill perfection
Favorite Skis: powder skis
Favorite boots: Scarpa T4
Occupation: Retired cement mason. Current job is to take my recreation as serious as I did my past employment.

Re: Physics debate

Post by lowangle al » Mon Jan 09, 2023 10:17 am

This is how I look at tip pressure. Let's assume your skis are mounted with your boot on boot center. When you put weight on that lead foot with even pressure from toe to heel the ski is weighted evenly. As soon as you put more weight towards your toes you are generating tip pressure. Any extra weight applied to the ski ahead of the boot center mark is tip pressure in my book.

"Tip pressure" as a term has been around a long time, it is what it is, no need to change it.



Post Reply