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Calculating speed and trajectory for a backcountry jump

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yungsteeze
Posts: 673 - Karma: 1,969
Me and my friend have been looking around for a sick place to build a nice backcountry 30 footer. Does anybody have any idea how to calculate the speed and trajectory necessary to clear a step over given distance and weight? Prob not lol but worth a try. Way too pumped for ski season. This is probably a really gay advanced equation which isn't worth it but idk
Jul 6 2014 6:35PM
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johnk
Posts: 232 - Karma: 2,646
fuck that send it
Jul 6 2014 6:55PM
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250r
Posts: 2274 - Karma: 1,020
is it a 30 foot wide 200 foot deep crevasse your planning on jumping? if not don't worry about it...its 30 feet.
Jul 6 2014 8:12PM
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ilikefood
Posts: 391 - Karma: 769
when building any sort of jump for a snow sport there are simply too many variables to actually calculate what speed you will need/where you will need to start the in run from to get to the landing.
So yeah just go for it.
Jul 6 2014 8:38PM
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.S.B.
Posts: 163 - Karma: 680
distance x gnar + trick = steeze

just go for it, you've probably hit 30 footers before, now it's just not in the park.
Jul 6 2014 8:39PM
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NinetyFour
Posts: 8650 - Karma: 13,409
This is the part in films where the rider gives a snowball a good toss from the lip, subtracts a few fucks so he doesn't have anymore fucks to give, then mans up and sends it. It's really a simple calculation if you ask me.
Jul 6 2014 9:45PM
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broto
Posts: 9039 - Karma: 25,658
it's possible to do it with some simple physics knowledge but being safe and calculated does not get you far in skiing, especially for such a relatively low risk jump
Jul 6 2014 9:55PM
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Heart
Posts: 6156 - Karma: 3,462
Eyeball it and the send it. I know math goes into consideration for big park jumps but unless you bc booter is huge I think you just need to nut up. Toss a couple snowballs and then send it, and remember, too big is better than too little.
Jul 6 2014 10:01PM
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Download-My-Apps
Posts: 5069 - Karma: 1,017
would you have a way of measuring your speed even if you calculated it?
Jul 6 2014 10:07PM
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yungsteeze
Posts: 673 - Karma: 1,969
Download-My-Appswould you have a way of measuring your speed even if you calculated it?


I actually have a friend with a radar gun. But I guess I'm probably being too technical about it because it wouldn't be an easy thing to figure out with maths lol
Jul 6 2014 10:26PM
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tac0.slayer
Posts: 254 - Karma: 947
Just make sure to always bring your protractor and tape measure in the BC
Jul 6 2014 10:38PM
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Download-My-Apps
Posts: 5069 - Karma: 1,017
yungsteezeI actually have a friend with a radar gun. But I guess I'm probably being too technical about it because it wouldn't be an easy thing to figure out with maths lol


It would be fairly basic math for purely speed and the jump itself. But then you would need someway for measure wind and temperature changes and would have to modify them each jump.
Jul 6 2014 11:14PM
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Casey
Posts: 7781 - Karma: 23,429
Most jumps I've built have no gap to clear and basically endless landing. It makes it more difficult to screw it up.
Jul 6 2014 11:44PM
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toastyteenagers
Posts: 1834 - Karma: 6,793
Northvansebdistance x gnar + trick = steeze

just go for it, you've probably hit 30 footers before, now it's just not in the park.


I agree.

also, if your gapping something, throw a snowball 3 times across it, if 2/3 snowballs make it, so will you.
Jul 7 2014 12:36AM
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Ribss.
Posts: 3442 - Karma: 3,344
NinetyFourThis is the part in films where the rider gives a snowball a good toss from the lip, subtracts a few fucks so he doesn't have anymore fucks to give, then mans up and sends it. It's really a simple calculation if you ask me.


Spot on good chap.
Jul 7 2014 12:52AM
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TWoods
Posts: 10014 - Karma: 8,385
It's just something you have to get a feel for. The hardest part when you build your first jumps isn't figuring out how fast you need to go, but how to build a wedge that isn't super awkward and terrible to hit.
Jul 7 2014 2:31PM
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cobra_commander
Posts: 16909 - Karma: 4,682
9.8 m/s/s...

It's not like you are trying to reach escape velocity, so no, it's not rocket science...
Jul 7 2014 2:46PM
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Skibumsmith
Posts: 5414 - Karma: 11,608
some equations you can use

to find the distance in the vertical direction you’ll fall:
y = y0 + V0 sin(θ)t - 1/2gt^2
Solve for time.

Plug ‘t’ into: x = V0cos(θ)t
to find the horizontal distance you’ll travel.

Make adjustments to your initial velocity and ramp angle using:
x = (V02/g)sin(2θ)

Calculate the length of your inrun.
mgh + ∫μkmgcos(θ)dx = 1/2mv^2
dx is how the angle of your inrun is changing with respect to x (so good luck calculating that)
you’ll also need to figure out the coefficient of friction between your skis and the snow

but you'd do better to just ask yourself where "would big air dave drop?" and then side step up 50 more feet from there.
Jul 8 2014 2:19AM
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toastyteenagers
Posts: 1834 - Karma: 6,793
Skibumsmithsome equations you can use

to find the distance in the vertical direction you’ll fall:
y = y0 + V0 sin(θ)t - 1/2gt^2
Solve for time.

Plug ‘t’ into: x = V0cos(θ)t
to find the horizontal distance you’ll travel.

Make adjustments to your initial velocity and ramp angle using:
x = (V02/g)sin(2θ)

Calculate the length of your inrun.
mgh + ∫μkmgcos(θ)dx = 1/2mv^2
dx is how the angle of your inrun is changing with respect to x (so good luck calculating that)
you’ll also need to figure out the coefficient of friction between your skis and the snow

but you'd do better to just ask yourself where "would big air dave drop?" and then side step up 50 more feet from there.


I recromend taking your devilish math and leave newschoolers.
Jul 8 2014 3:14PM
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Jooky
Posts: 1239 - Karma: 37
No sarcasm here....just trying to help:

Build your wedge, and try to eyeball the trajectory that it will send you.

Then, try to estimate the high point of your flight (should be in the middle between takeoff and landing). Throwing a snowball can help too.

Then estimate where you want to start your in-run. This start point MUST be higher on snow than the high point of your trajectory.

Speed check it once, see if speed seems reasonable.

Huck.

Land.

Ride away clean.

Afterbang.

Claim.

Hope this helps.
Jul 8 2014 3:22PM
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HORK
Posts: 100 - Karma: 1,785
^profit
Jul 8 2014 5:56PM
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freestyler540
Posts: 13044 - Karma: 18,270
your worried about 30 feet? take you panties off and build that sucka to 90 feet
Jul 8 2014 6:31PM
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Rusticles
Posts: 2178 - Karma: 1,333
TWoodsIt's just something you have to get a feel for. The hardest part when you build your first jumps isn't figuring out how fast you need to go, but how to build a wedge that isn't super awkward and terrible to hit.


This is going to be far more important than speed.

Remember to make the wedge a hell of a lot longer than you think as well as an increasing angle of takeoff, not just a perfect triangle.
Jul 9 2014 10:18AM
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