How to tuck

[LandLockedboardingGS]

Mathematically, terminal velocity is given by

see derivation
where

Vt is the terminal velocity,
m is the mass of the falling object,
g is gravitational acceleration at the Earth's surface,
Cd is the drag coefficient,
ρ is the density of the fluid the object is falling through, and
A is the object's cross-sectional area.
So it can be said that, on Earth, the terminal velocity of an object changes due to the properties of the fluid, mass and the cross sectional area of the object.

This equation is derived from the drag equation by setting drag equal to mg, the gravitational force on the object.

Note that the density increases with decreasing altitude, ca. 1% per 80 m (see barometric formula). Therefore, for every 160 m of falling, the "terminal" velocity decreases 1%. After reaching the local terminal velocity, while continuing the fall, speed decreases to change with the local terminal velocity.

[audacity]

fat equals bad tuck and inability to hold tucks over long distances

not necessarily, that guy at Teutonia seemed to keep up with K-Rimes just fine, and hold his tuck, come on now, stereotyping is for losers.

[SgtSparkles]

he didn't seem fat, just stalky....i mean FAT where you can't tuck as low cause your stomache gets in teh way

[soulrider]

hey, i was wondering whether the type of leathers you have affect your speed?

i came up with an ingenious idea.......wear one of those rubber swimsuits in a race!!

[Metalhead8290]

The main reason to wear leathers is not to be aero, but to protect yourself in a crash. Some people do wear speed suits. Kind of like the "swim suit" you were talking about, but more practical.

[soulrider]

thanks, where can i get leathers? i wanna really get into dh. the fastest i've gone though is in the early thirties.

[Xgecko]

thanks, where can i get leathers? i wanna really get into dh. the fastest i've gone though is in the early thirties.

Ebay try not to buy Perf leather or anything with to much fabric instead of leather

[jlmitch]

If y'all are talking about the Fastskins from Speedo and other companies, those aren't rubber, they're just regular nylon and spandex, with special construction to reduce water drag and muscle fatigue. I dunno, that which reduces water drag should reduce air drag, as well. It could work if you were completely sure you weren't going to fall; that suit -and your skin- would be toast. For $400 I would just get a speedsuit for air, since that's what you're racing in.

[AJ]

if you're gonna buy a speedsuit (to wear over leathers, ofcourse ) dont buy one for swimming, get a speedski suit for air.
If you buy a one piece leather, you want the less patterns possible, that means more stitching will create more drag and in the end may snap open on impact.
A good example is everyone who owns NJKs, its all basic, one color, no pattern, maybe one stripe that all.
Stay away from Cordura.
-AJ

[*SWEET*]

Very nice pic of Mischo there (also known as "quasimodo" after this pic )
Love it

[anotherartgeek]

This, although sometimes too technical, I only understood 1/10 of all the physics stuff, has been very informative. What I know about DH skating couldn't fill a thimble. But now I think I have an idea about where to start. Thank you all.

[rusty1]

thats how i tuck

[Willl]

he didn't seem fat, just stalky....i mean FAT where you can't tuck as low cause your stomache gets in teh way

This is true. I rode with someone who was fat and he had to almost stand up and he couldn't get very low or fast. It was fun to draft him but he just got in the way.

[Karv]

Your weight "advantage" only gives you a higher terminal velocity than a lighter rider of the same size. You and the other skater both accelerate at the same rate, and only stop accelerating when the wind resistance pushing on you is equal to the component of gravity pulling you forward. The more massive rider gets more gravity pulling on him (that's what we call weight) so if both riders are the same size and have the same tuck, the heavier rider will top out at a higher speed. (On the same hill.)

Whatever you get out of weight will only show up as your speed exceeds the terminal velocity of the other skater. Below the other skater's terminal velocity, you two will (ideally) be going the same speed from a standing start. For a medium-steep hill and a good tuck, 30ish sounds about right.

The heavier you are, the longer it takes to accelerate, but the longer you stay in motion.
The lighter is vice versa.

Newton's Second Law

[enemy combatant]

The heavier you are, the longer it takes to accelerate, but the longer you stay in motion.
The lighter is vice versa.

Newton's Second Law

That is completely wrong! You haven't understood anything in this thread nor anything about the Laws of Motion.

Newton's Second Law

It is about mass vs. aerodynamic drag. If a lighter rider has the same aerodynamic drag coefficient as a heavier rider they will accelerate at the same rate.

[hexagon5un]

The heavier you are, the longer it takes to accelerate, but the longer you stay in motion.
The lighter is vice versa.
Newton's Second Law

True (almost -- it's actually the heavier you are the more force it takes you to accelerate). But think about what force makes skaters accelerate, and keep going further along that Newtonian path to reach: Gravity. So F=ma (or a = F/m), but F=mg due to gravity. a = g. Irrespective of m.

OT: that Mischo tuck looks sweet. Put that in your windtunnel and smoke it.

[enemy combatant]

True (almost -- it's actually the heavier you are the more force it takes you to accelerate). But think about what force makes skaters accelerate, and keep going further along that Newtonian path to reach: Gravity. So F=ma (or a = F/m), but F=mg due to gravity. a = g. Irrespective of m.

Of course it's true and not just "almost." Go to the site I posted much earlier in this thread about terminal velocity and it will explain it to you.

The acceleration of a light and heavy skater is the same precisely because it is irrespective of mass. What makes one skater faster or slower than another is the relative aerodynamic drag acting on each one. The absolute size or mass of the rider doesn't matter.

[audacity]

Of course it's true and not just "almost." Go to the site I posted much earlier in this thread about terminal velocity and it will explain it to you.

The acceleration of a light and heavy skater is the same precisely because it is irrespective of mass. What makes one skater faster or slower than another is the relative aerodynamic drag acting on each one. The absolute size or mass of the rider doesn't matter.

thanks for being considerate of other peoples opinions.

douchebag

[mc99david]

i've changed my tuck around a bit and just wondering what you all think. I used to ride brazilian but it wasnt very airo because my legs wouldnt be in line with my other leg, so i started puting my back knee in the heal of my shoe, and it seems to be working pretty good for me, but what do you guys think? now i'm not riding, so its probably a little bit differnt than this, but heres what i've got.

[Jam]

David, I like your tuck. In my experience and opinion, I say screw the whole "If your back is not flat then your tuck is not good." The only thing I would say to watch out for (and you can learn this the very hard way, too) is when you are coming in and out of tuck. I was going down a course and had to get up and airbrake, and it just so happened that my knee was a little too comfy....in short, it was terribly dificult/frightening to get up to airbrake. Then again, that probably only happens when one's knee is actually on the board. Nice tuck!