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Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory?
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Poll: Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory?
Yes 40 / 57%
No 30 / 43%
70 total votes
 
yuri_base

Jan 20, 2012, 4:55 PM
Post #1 of 30 (16566 views)
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Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? Can't Post

Curious as to what percentage of wingsuit pilots didn't know this before (see this post in discussion of Jeb's accident).

yuri_base

Jan 20, 2012, 6:50 PM
Post #2 of 30 (16453 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

To rephrase a bit to avoid confusion of what is lower relative to what:

Imagine you're in sustained flight juuuust above a soft snowy slope. The slope matches your glide perfectly. You get closer, and closer, and closer. Will you start dragging snow with your chest first? or feet? (for simplicity, let's think that you're fully pointing your toes back, so toes are not "dropping" down as they usually are)

If the latter, how high you think your head will be above snow?

Again, just imaginary situation when you're just lightly touching fresh snow and it's not slowing you down or causing you to crash.

yuri_base

Jan 20, 2012, 7:35 PM
Post #3 of 30 (16415 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

And another imaginary (or not?) scenario: you're highly experienced proximity pilot, on top of your game, very current and feeling very good about your flying. You're best in the world, period. The air is incredibly smooth, and you cut through the air like skater on ice - super precise, super smooth. It's like you're a ruby on rails. You have a GoPro mounted on your chest strap on a very short mount. You fly above a constant slope with trees of constant height, and you feel sooo precise that you decide to get a cool footage where your GoPro juuust lightly slaps the treetops. Juuust a fraction of an inch (you're that precise!). Will you get this cool video and become a super rad legend worshiped by your peers and youtube whores alike? Or what will happen?

Don't ask me what I'm smoking. Blush You can't afford it. Laugh


(This post was edited by yuri_base on Jan 20, 2012, 7:47 PM)

base283

Jan 21, 2012, 12:45 AM
Post #4 of 30 (16260 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

Isnt that similar to saying "did you know that sides of your auto travel on a trajectory 1 to 4ft to the side of eyes' trajectory?"?
Take care,
space

vesatoro

Jan 21, 2012, 12:53 AM
Post #5 of 30 (16254 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

If one is flying with any reasonable margin for error, this really does not matter at all.

V


(This post was edited by vesatoro on Jan 21, 2012, 6:06 AM)

-rm

Jan 21, 2012, 5:11 AM
Post #6 of 30 (16157 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

I've only just ordered my first wingsuit, but there's one thing I wonder:
An airplane, when it takes off, uses flaps. Then, when it gains speed, the flaps are rolled in, making the camber of the wing smaller at higher speeds. Is there a similar dynamic happening in wingsuit flight? If there is: is it possible to have a stationary flight in which the eye's trajectory is lower than the feet's trajectory? (It certainly *feels* so in skydiving and tracking)

TransientCW

Jan 21, 2012, 6:47 AM
Post #7 of 30 (16113 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

mad respect to you yuri, and i dont know you , but it seems you are still dwelling on this you vs. wwarped argument, and you possibly have dropped several doses of strong liquid over the evening which may have intensified these feelings.............?

you didnt put an option for:
who gives a fuck, i dont plan on becoming a proxy flyer

GreenMachine

Jan 21, 2012, 8:28 AM
Post #8 of 30 (16053 views)
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Flying A 'Sleeping Bag of Death' (SBD) [In reply to] Can't Post

I did not vote because: never flown a wingsuit
(just camera wings, track pants, tracking suit)

I agree with
TransientCW, I have zero fucking
desire to drag my tiny balls along tree tops
and mountain rocks at 80 miles per hour.

Space BASE283 asked:

Isn't that similar to saying "did you know that
sides of your auto travel on a trajectory of 1ft
to 4ft beyond your eyes' trajectory?
" ?

Sadly, not really sir...

1) Automobiles usually travel in only 2 directions Wink

2) Many American drivers steer their cars in ways
blatantly revealing they have really only a vague
notion about its actual size, especially SUVs Unsure

3) It probably wouldn't take Yuri a dozen posts
to explain/convince Wwarped of this car fact Tongue

4) I have seen SKY jumpers smack their cameras
climbing out or snag their wing tips on landing Unimpressed

5) 41% of respondents said they did not know it
while most drivers would probably never admit Crazy


I am ignorant and curious about a few of these
flight concepts discussed since Jeb's Touch & Go
but will start a new thread to ask my questions.

yuri_base

Jan 21, 2012, 8:40 AM
Post #9 of 30 (16040 views)
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Re: [base283] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

base283 wrote:
Isnt that similar to saying "did you know that sides of your auto travel on a trajectory 1 to 4ft to the side of eyes' trajectory?"?
Take care,
space

No. Your example is obvious, as is asking wingsuiter if he knows that his left hand is on the left and right on right.

Where feet are in relation to head in flight is not as obvious as it seems when you read the answer. The poll right now shows that about 1 in 3 pilots didn't know that. Many people think (backed by feeling inflight) that since body is tilted a bit headdown, head is flying lower than feet, and thus if head clears an obstacle, the whole body does. And that's wrong.

yuri_base

Jan 21, 2012, 8:47 AM
Post #10 of 30 (16027 views)
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Re: [TransientCW] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

TransientCW wrote:
mad respect to you yuri, and i dont know you , but it seems you are still dwelling on this you vs. wwarped argument, and you possibly have dropped several doses of strong liquid over the evening which may have intensified these feelings.............?

you didnt put an option for:
who gives a fuck, i dont plan on becoming a proxy flyer

Liquid or gas, I don't give a proxy flying fuck about what you plan on becoming. Wink But shame on you for not licking the snow inflight or slapping treetops with their GoPros - all the cool kids in town are now doing that! Tongue

The poll clearly shows that as of this writing, 12 pilots (or about 1 out of 3) didn't know a fact that someday may save their lives. And we now know several pilots who got killed or injured as a result of not knowing this fact. QED. Angelic

yuri_base

Jan 21, 2012, 8:58 AM
Post #11 of 30 (16012 views)
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Re: [GreenMachine] Flying A 'Sleeping Bag of Death' (SBD) [In reply to] Can't Post

GreenMachine wrote:
I have zero fucking
desire to drag my tiny balls along tree tops
and mountain rocks at 80 miles per hour.


Regardless of your desire or presence of a zipper in appropriate place, you can't drag your balls on surface while flying wingsuit. Well, unless you have balls that hang 1-2ft out. In which case, they'll be blown by the wind anyway. You'll need some kind of pushup bra to prop them, if you were really determined to drag them. Cool

yuri_base

Jan 21, 2012, 9:11 AM
Post #12 of 30 (15997 views)
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Re: [GreenMachine] Flying A 'Sleeping Bag of Death' (SBD) [In reply to] Can't Post

A quick rule of thumb to determine one's ability to drag balls on surface while flying wingsuit: do a push-up. With your arms extended and body straight or slightly dearched, see if you can touch the floor with your balls. If you can't, you need to grow your balls. It's simple geometry, really.

johenrik

Jan 21, 2012, 10:01 AM
Post #13 of 30 (15954 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

I don't really agree on this. When proximity flying and getting very close we fly very steep. Full speed with the legs, but arms back. This makes us fly in a lot more straight, but steep, line where head and legs are in about the same trajectory.

I agree that on a "normal" wingsuit jump where one are working on the best glide ratio the issue is like the pictures in the other thread, but for good proxy flights this is not the case. Just look at the first scene from Phoenix Fly's new video (Insight). It shows it pretty clearly.

Unfortunately a lot of new proxy flyers don't know this and fly more like they would normally even when proxy flying, but thats a whole different story. I also hardly doubt this had anything to do with Jeb's accident.

Edited to add: As long as you don't go head down it always will be a small difference, but if you got 2-4 feet you are doing something wrong...


(This post was edited by johenrik on Jan 21, 2012, 1:19 PM)

jakee

Jan 21, 2012, 11:20 AM
Post #14 of 30 (15900 views)
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Re: [-rm] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

-rm wrote:
If there is: is it possible to have a stationary flight in which the eye's trajectory is lower than the feet's trajectory? (It certainly *feels* so in skydiving and tracking)

It feels like the wind's hitting you in the back?

How well do you think this setup would fly?

-rm

Jan 21, 2012, 11:44 AM
Post #15 of 30 (15882 views)
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Re: [jakee] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

When I'm in a good track, it feels as though my legs are being sucked above my head, about to topple me over. To be conservative, I go a little flat, so I don't end up head down. When going really fast, a wing can get positive camber; I.e. the trailing edge is above the leading edge. I just wonder if that also applies to the wingsuit jumper. I am of course not thinking of mere reflection, jakee. Suction forces are 4x bigger for windmills.

jakee

Jan 21, 2012, 11:52 AM
Post #16 of 30 (15873 views)
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Re: [-rm] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

In reply to:
When I'm in a good track, it feels as though my legs are being sucked above my head, about to topple me over.

And why do you think this means that the wind is hitting you in the back?

In reply to:
When going really fast, a wing can get positive camber

Wingsuits do not go really fast, and camber is a feature of an aerofoil cross section.


(This post was edited by jakee on Jan 21, 2012, 12:40 PM)
Attachments: AoA.png (9.09 KB)

yuri_base

Jan 21, 2012, 12:20 PM
Post #17 of 30 (15851 views)
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Re: [-rm] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

-rm wrote:
When I'm in a good track, it feels as though my legs are being sucked above my head, about to topple me over.

Exactly. Unless we specifically thought out the situation before, we go by feeling, and I bet Maggot's balls that most people's feeling inflight is that their body is stretched parallel to airflow, like Superman's, and that their head and feet are on the same level relative to trajectory. But what we feel is wrong and can potentially be lethal.

Suppose you're in plain clothes track and glide ratio GR = 0.8. Your glide angle is therefore GA = atan(1/GR) = 51 degrees to horizon. Your body will be somewhat headdown, let's say, your pitch P = 15 degrees to horizon. Thus, the angle between the relative wind (your trajectory) and your body is (angle of attack) AoA = GA - P = 51 - 15 = 36 degrees. If you're 6ft tall, your feet therefore are flying 6*sin(36) = 3.5ft below your head's trajectory.

If you're in tracking suit and your GR = 1.4, then GA = 36 degrees, and if pitch is the same, P = 15 degrees, then AoA = GA - P = 21 degrees, and your feet are flying 6*sin(21) = 2.2ft below head.

Regardless of what we feel.

-rm

Jan 21, 2012, 12:30 PM
Post #18 of 30 (15836 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

Ok, but say you're actually trying to fly head down, and you're just a little off. You get tremendous speed in a horizontal direction. As I said, I only just ordered my ws :P

yuri_base

Jan 21, 2012, 1:10 PM
Post #19 of 30 (15811 views)
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Re: [-rm] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

-rm wrote:
Ok, but say you're actually trying to fly head down, and you're just a little off.

Yes, depending on your flight mode (angle of attack), your wetted area will be different (and this is what Jo Henrick also made a good point about above). But it's essential to be aware of this simple phenomenon at all times when flying above objects. You may give yourself a "safe" margin of 10-20 meters and then, oh shit, you fly into a big high-humidity pocket with lower air density, or there's a strong downdraft (or a side gust), or a wing zipper opened a bit and you're not getting as much lift, or something else... and you no longer have your margin. In this case, the amount of correction you need is bigger than what you feel and what your eyes tell you.

wwarped
Moderator
Jan 21, 2012, 5:57 PM
Post #20 of 30 (15695 views)
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Re: [-rm] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

-rm wrote:
When I'm in a good track, it feels as though my legs are being sucked above my head, about to topple me over.

this may or may not apply to you...

a wing generating lift also creates a moment that wants to pitch the nose down (as you describe).

standard configuration planes (such as a Twin Otter), have tails that create a down force to keep the nose from dropping.

back to Yuri's topic...

RayLosli

Jan 21, 2012, 9:39 PM
Post #21 of 30 (15645 views)
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Re: [wwarped] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

WTF ??? . God I am not believing I am reading this Thread & want 5 minutes of my life back . just from the fact that you are NOT FLYING FORWARD . but Falling DOWNWARD in a GLIDE Angle ? .
SIMPLY SAYING . 2 to 1 / 3 to 1 / 4 to 1, Glide Angle . Of Fucking Course your Feet are going to be passing & ( FOLLOWING LOWER ) in relationship to where your Head just past 100th of second earlier when Gliding at downward Angle & passing over a fixed/STATIONARY ground position . You don't need discussions of Flight or generated Lift or disruptive angle of flight due to the Coriolis effect. or gravitational pull of the fucking Moon .
I am Not A PROXY FLIER & I SAY FUCKING ... DUUuuuuuuHHhhhh . & Why is this a Poll ???? OHHhhh now I remember . It's BASE.com & the reason they got the volume of BASE chat is because it's full of FLUFF .
.

yuri_base

Jan 22, 2012, 12:39 AM
Post #22 of 30 (15602 views)
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Re: [RayLosli] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

RayLosli wrote:
WTF ??? . God I am not believing I am reading this Thread & want 5 minutes of my life back . just from the fact that you are NOT FLYING FORWARD . but Falling DOWNWARD in a GLIDE Angle ? .
SIMPLY SAYING . 2 to 1 / 3 to 1 / 4 to 1, Glide Angle . Of Fucking Course your Feet are going to be passing & ( FOLLOWING LOWER ) in relationship to where your Head just past 100th of second earlier when Gliding at downward Angle & passing over a fixed/STATIONARY ground position . You don't need discussions of Flight or generated Lift or disruptive angle of flight due to the Coriolis effect. or gravitational pull of the fucking Moon .
I am Not A PROXY FLIER & I SAY FUCKING ... DUUuuuuuuHHhhhh . & Why is this a Poll ???? OHHhhh now I remember . It's BASE.com & the reason they got the volume of BASE chat is because it's full of FLUFF .
.

I'll leave it to TransientCW's forensic analysis to find out whether a liquid or gaseous substance was involved in writing the quoted post. Wink

wwarped
Moderator
Jan 22, 2012, 10:04 AM
Post #23 of 30 (15488 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

the practical value of this theory is highly dependent on how a wingsuiter flies.

when in a max glide configuration, they will lack options in case they get the approach angle wrong.

if NOT in a max glide configuration, they have more options as they near an obstacle. but not knowing their body position, precludes any calculation.

an ankle camera might provide data to be interpreted rather than fixating on potentially misapplied theory.

434

Feb 11, 2012, 3:38 AM
Post #24 of 30 (14681 views)
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Re: [yuri_base] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

In this video from 1:26 you will se two different approaches in Trollstigen from Bispen.

http://www.youtube.com/...x=1&feature=plcp


(This post was edited by 434 on Feb 11, 2012, 4:17 AM)

Hellis

Feb 11, 2012, 5:07 AM
Post #25 of 30 (14652 views)
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Re: [434] Wingsuiters: did you know that feet travel on a trajectory 1 to 4ft below eyes' trajectory? [In reply to] Can't Post

Nice view.

It looks like the feet are aprox 1.5 feet below the head.
But then the feet are behind too.
Attachments: Flyby.JPG (65.1 KB)

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