Sessions Longboard à Montréal

organizer sets the rules

apres ca sous la chaise...

Je suis in! Sauf que j'en ai jamais fait de ma vie.
Faut que j'essaie mon matos.

now that's the spirit!!!!!

I thought I'd do a few calculations to figure out just how fast a snowboarder should be able to go.

Obviously, the steeper the slope the higher speeds that are possible. I decided to do the calculations using a slope of 38 degrees. That's the incline that Wikipedia says is the most likely to have avalanches induced by human activity (snowboarding, skiing, hiking, etc.)

When you bomb a hill on a snowboard , you have basically three forces to deal with.

- Gravity pulling you down. Of course, the ground below you gets in the way, preventing you from falling straight to the center of the earth, but some of the force of gravity ends up getting directed along the face of the hill, pulling you along the surface and down to the lifts so you can start back up again.

- Air Drag pushing back against you. The thing about drag is it increases much more as you speed up than you might expect. If you double your speed, the drag quadruples.

- Friction. Unlike drag, friction stays relatively constant regardless of your speed down the hill. Although, this isn't exactly true, it's a good approximation. All kinds of things affect the amount of friction you encounter on snow, from the temperature of the snow to it's texture. It's likely that sliding friction changes at least a little as you speed up, but the change is probably pretty small, at least on the firmly packed snow where speed records are set.

Gravity pulls you down the hill, while drag and friction are directed back up the hill. As you build up speed down a slope, the forces of gravity and friction stay constant (provided the slope doesn't change). The drag, on the other hand increases until the forces pulling you down and the forces pushing back up balance out. At that point, you've reached terminal velocity for the hill.

For those of you who like equations, terminal velocity occurs when

Force of gravity = Drag Force + Frictional Force


To cut to the chase, if you assume a 70 kilogram (154 Lbs) snowboarder standing straight up on their way down the slope (giving them a frontal area I estimate to be about 0.5 square meters), with a drag coefficient of about 1 (which Wikipedia tells me is typical of skiers, and is probably about right for snowboarders), a friction coefficient of 0.04 (typical for waxed surfaces on packed snow), and a 38 degree slope, you get a top speed of about . . . 80 mph (129 kph).

Go into a racing tuck, put on a racing helmet and some slick racing clothes, and you can pretty easily push that up over 125 mph (200 kph), which is coincidentally just about the top speed record on a snowboard.

In fact, the fastest speed possible on a 38 degree slope is probably much higher. I made some pretty conservative guesses in doing these calculations, and didn't consider aerodynamics much at all. In fact, the skiing speed record of about 156 mph (252.4 kph), which was set under similar conditions that I used in my calculations, shows that there's lots of room to improve snowboard speed records.

http://www.worldsfastestsnowboarder.com/

SICK!!

HEY , J'ESPERE QU' IL VA AVOIR UN QUELQUES RIDERS AVEC DES BOARDS DE RACE, ILS DISENT TOUJOURS QUI SONT PLUS RAPIDE QUE LES BOARDS ORDINAIRE.... COLOR 13, WAYAN ?????

Fred, ils sont vite les dudes en ski board
Je vais inviter les kids du mont Blanc que je coach.

Va falloir que je teste la chose avant. Pour tout de suite je ride mon Gnu 167 wide et mes télés. Niko tu as un canting a me passer? J'en ai juste un. Si tu vois ton bro, il ma dit qu'il m'en donnait un.

Pour rajouter a ton exposé de vitesse, mon cher Fred, je dirais que dans le concept de ta course, il y a a considerer la vitesse perdues dans les virages.

J'aimerais bien si un ami nerdy qui possede un GPS enregistrant le top speed voudrait bien venir rider a Olympia un vendredi ou samedi soir. J'ai une passe là et j'me tape des chinese downhill en tuck dans l'Aiguille de Piedmont pis ca clanche en sale. J'aimerais bien savoir comment vite ca fait.

si y'a ben des riders qui viennent a avila attack, j'amerais organiser une derniere course a olympia dans les aiguilles.. straight down...full speed!! ca serait mongol!!!

Je clanche mon chum ben raide parce que je tuck et que je choke pas.

lets go to olympia next time
jaimerais ca...la ligne droite

Oui! Louons la montagne.

Woa c'est vrai! Il me semble qu'on peut louer Olympia pour pas tellement cher et ça inclus un souper! Ça pourrait vraiment être cool

On pourrais dire qu'on est un groupe de naturiste qui veut pouvoir skier a poil. A moins que vous ayez d'autres bonnes idées? This thread is outta control!

oui on peut louer le mont olympia... mais ca prendrait au moins 40 a 50 riders pour que ca marche...
ca fait parti de mes plans, mais avant , faut recruter plus d'adeptes...
alors, invitez vos friends a joindre le group MISSILE RACING et invitez vos amis au AVILA ATTACK...
PEUT-ETRE QU'UN JOUR ONT SERA ASSER DE RIDERS POUR QUE CA CE REALISE..

mais en attendant, ont peux toujours faire un OLYMPIA ATTACK sans louer la montagne... ca depend du turn out du prochain AVILA ATTACK... 30 riders ou plus et je l'annoncerais pour la fin mars.