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yuri_base

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You have missed the point but since you are Dutch it is normal for you! :P

If you think that there is no lift generated but only deflecting, maximum will be achieved when there is maximum surface presented to the flow.
Meaning the most efficient will be belly falling straight to the earth.
Video shows that airflows separate but it does not mean that there is no lift generated.

Imagine Leder Wing Suit!?!?! B|

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The footage we've seen so far, visualising the airflow over the wing suggests the airflow seperates before even hitting further then 1/3d up the wing. There's also some single-layer wingsuits out there get more then decent glideratios and flight times..

As 'filled with poopoo' you may find that statement..just looking at the videolink he posted along with it should at least be some food for thought..;)



Indeed... In a way I agree with Yuri that we should be doing more research stuff (like putting the threads on the wingsuit to see the airflow). It now seems we just do too much guesswork and estimations and thinking it will work in a particular way without adequately testing it.
Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

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rough stuff isn't to slow air down. its to keep the boundary layer turbulent, which keeps it attached to the wing longer, which gives you more lift. thats why the balls have dimples. so you'd want rough stuff on the top of the wing.

i don't think we're there yet on wing suits, i dunno but im guessing our boundary layers are pretty damn turbulent as things are.



Bird-Man had the deflectors on the S3, S3S and the S6, exactly for this reason, to keep the turbulent flow longer on the wing. I guess on the Blade it was no longer deemed as useful and taken off.

Unfortunately the flow over the top of the wing seems to separate almost immediately, as you can see in this revealing video making the whole idea of an airfoil shape on your wingsuit laughable. However much we would like to believe otherwise, what we "fly" are nothing more really than air deflectors, which is why Tony's 1 layer suit can actually "fly" pretty well with 2 layer wingsuits.



I found the video very difficult to interpret. Where was the camera, and what was it looking at?

The flow separation isn't at all surprising given the nature of the "airfoils" and the AoA at which they are flown.
...

The only sure way to survive a canopy collision is not to have one.

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well im ready to try vacuum boundary layer suction on my wingsuit, the tiny fans are gonna suck from the top of my wing then also inflate into the wing itself. all powered by 50 9 volt batteries placed around the wingsuit, orrr 1 big battery, feeding the vacuums through christmas tree lights, which will in turn make me look super sick and lit up as my boundary layers are far more attached than the rest of yous's



It might just work but if you clog the breather ports with moisture or dirt from those dusty aircraft then you just might end up like a vacuumed bagged slab of meat.

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The point is, we reached the end of the road. We maxed out the size of fabric, but we haven't applied any of the basic aerodynamics ideas to it.



To be honest, without discussing things like
rigid wings and such, there's only so much aerodynamics to bring to bear on this problem. Wing suiting is really nothing more than an assisted track. The vast majority of what is going on is the generation of thrust by redirecting the airflow and a resistence to falling (drag). I've no hard data but I'd be surprised if there is any laminar "lift" going on with the "wings". Their shape is imporant to minimizing resistence to horizontal motion (drag) and to efficiently diverting the air to generate maximum "thrust". But I'd be surprised if the airflow over the top of the wings was anything but turbulent. IF I were to explore anything in this regard it would almost assuredly be "vortex generators" on my arms to try to "reattach" the flow on the top of the wings. That generates drag however and I'm not sure if it is worth it.

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A canopy flies at say 3-3.5:1 and most accept that it generates lift. A wingsuit flying at between 2.5-3:1 does not..?

From the tests we have made it appears to be a combination of vortex / conventional lift.

Don't believe me? Ok, get your needle and thread out :)



I think you guys are saying the same thing, you just have different definitions of what "significant" is.
www.WingsuitPhotos.com

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Looks like basic are ignored (again and again)... [:/][:/][:/]
I suggest to all of you with doubts to read WS flying and Basics of Aerodynamics 1 and 2 here http://www.phoenix-fly.com/articles.htm.

Concerning videos of wing suit airflow, have you seen how airflow looks on our skydiving canopies?
I think many of you will be surprised - I was...

To all of you with doubts - "Is there any lift in wing suit flying?" or "Wing suiting is really nothing more than an assisted track", few questions:
V2 is at least 30% - 35% faster than Stealth and have less wing area but it have about the same (or better) glide ratio, why?
Good tracker is flying 1:1 or better, wing suit have way better than that. Why is wing suit better if it is just "assisted track"?

To all that are still having problem with terms "laminar", please read this article (again and again):
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2683420;#2683420


Many of skydivers are trapped with time and vertical speed as the only relevant factors in WS flying.
In one of my previous posts, one of the posters wrote me: "The way I read it, though, leads me to believe that you guys think that all we here in the states care about is vertical speed.".
Looks like it is becoming more and more true... If it is so, Para Foli's or Manta's will be the best skydiving canopy....

Boris

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Here's a table illustrating the "significance". At L/D = 1.0 - typical glide ratio for lazy flocks - both lift and drag are 71% of the weight. So we can say that drag is as significant for flocking as lift. :) At L/D = 2.5, lift is 93% of weight and drag is 37%. For a high-end sailplane with L/D = 80, lift is 99.99% of weight and drag is only 1%, but we can't say that this tiny drag is insignificant, because they put a lot of research and $$ to get that 1%. ;)



L/D Lift/Weight Drag/Weight

0 0.00 1.00
0.5 0.45 0.89
1 0.71 0.71
1.5 0.83 0.55
2 0.89 0.45
2.5 0.93 0.37
3 0.95 0.32
3.5 0.962 0.275
4 0.970 0.243
4.5 0.976 0.217
5 0.981 0.196
6 0.986 0.164
7 0.990 0.141
8 0.992 0.124
9 0.994 0.110
10 0.995 0.100
12 0.99655 0.08305
14 0.99746 0.07125
16 0.99805 0.06238
18 0.99846 0.05547
20 0.99875 0.04994
25 0.99920 0.03997
30 0.99944 0.03331
35 0.99959 0.02856
40 0.99969 0.02499
45 0.99975 0.02222
50 0.99980 0.02000
60 0.99986 0.01666
70 0.99990 0.01428
80 0.99992 0.01250
90 0.99994 0.01111
100 0.99995 0.01000

Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Based on the numbers James posted (Stealth: L/D = 2.2, Vx = 65mph, Vy = 30mph (as derived from Vx by L/D given) and Vampire: L/D = 2.4, Vx = 100mph, Vy = 42mph (again, derived from Vx by L/D given)), we can get some insight into aerodynamic properties of Stealth and Vampire.

Simply plug these horizontal and vertical speeds into that spreadsheet with wingsuit equations and see what the adjusted lift and drag coefficients are.

For Stealth, they are Kl = 17.9, Kd = 8.12.
For Vampire, they are Kl = 7.86, Kd = 3.28.

(all times 10^-5, and in English units)

Adjusted coefficients Kl and Kd are proportional to nonadjusted (classic, dimensionless) coefficients Cl and Cd and inversely proportional to wingloading.

What is the total surface area of Stealth compared to Vampire? Robi and James could answer this question precisely, but suppose for a second that Stealth has 30% larger surface area.

So from the numbers above it follows that Stealth has the coefficient of lift Cl 1.75x higher than that of Vampire and coefficient of drag Cd 1.9x higher.

Is it good or bad? What does it tell us?

I think it tells us a lot. Since both lift and drag coefficients increased (almost doubled), while the lesser dampening effect of the body (due to larger area of the wings) should have decreased, that means two things.

First, it's misbalanced and the AoA settles on a too high a value. 2.2 corresponds to 24 degree glide angle, while 2.4 corresponds to 23 degrees. Not much of a difference, but what about the difference in pitch angle? Vampire is a steep suit: the pitch angle for best glide is below the horizon, usually from my experiences and observations of others, about 10-15 degrees below the horizon. That gives us AoA of about 8-13 degrees and results in very fast - and efficient, too - flight. What is the pitch angle for Stealth for 2.2? I wouldn't be surprised if it's flat with horizon or even slightly head-high, due to its overpoweringly large arm wing. That's at least 24 degree AoA. Slower and less efficient. Actually, as indicated by the above coefficients, a LOT less efficient. But in terms of L/D, part of this inefficiency is hidden by lesser dampening effect of the body since body now is smaller fraction of the total surface area.

Arms wings can be relaxed to get more steep pitch angle, but then it decreases efficiency by other mechanisms. Or you can bend in the waist more forward and again, efficiency is decreased because the wing is now distorted too much.

See, a lot of food for thought and further development can be extracted from just a couple of ordinary-looking numbers. ;)

Yuri
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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In reply to " I´ve done some bionics.
My first paper model of this wing concept amazed our simple minds when we made the first flight tests.

I´m busy with too many projects and there is no easy way for us to develop a wingsuit on that model at the moment.

I also got plans for two different wing structures (bionic science), which I like to combinate:

1. Electrostatic airfoil via "living strings" (intregration of moving synthetic fibre strings in air cells)
The concept from flies when they create electrostatic energy by scrubbing their legs and transfer it to their wings.

2. Surface in micro mushroom structure (I don´t eat them )


Every wingsuit manufactor with enough experience in 3D flexibles is welcome to work with us
.................................................................

Go the Jester!

can see this in combination with low density foam inners skinned with harder shell.
Twist activated multiflaps providing controllable burst of max lift (eg make a fist and thumbs-up twist it -twist it good.)
In combo with twist activated l.e. spoilers might even get a wingsuit that can... gasp...flare.

Now to get it to custom made stick to muscles for maximum usage of every muscle on bod just like real birdy. No wasted muscle usage equals ability to flap ie hold up body weight using all muscles not just tiny arm muscles.

gooey layer between suit and bod to provide full eletrostatic connection?

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I think most of this almost 2x increase in lift and drag coefficients comes from increases AoA due to incorrect balance of armwing and legwing surfaces. While the 10% decrease in performance is due to different wing planform and smaller aspect ratio.
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Based on the numbers James posted (Stealth: L/D = 2.2, Vx = 65mph, Vy = 30mph (as derived from Vx by L/D given) and Vampire: L/D = 2.4, Vx = 100mph, Vy = 42mph (again, derived from Vx by L/D given)), we can get some insight into aerodynamic properties of Stealth and Vampire.

Simply plug these horizontal and vertical speeds into that spreadsheet with wingsuit equations and see what the adjusted lift and drag coefficients are.

For Stealth, they are Kl = 17.9, Kd = 8.12.
For Vampire, they are Kl = 7.86, Kd = 3.28.

(all times 10^-5, and in English units)


Yuri



Assuming the raw data are correct!
...

The only sure way to survive a canopy collision is not to have one.

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can see this in combination with low density foam inners skinned with harder shell.
Twist activated multiflaps providing controllable burst of max lift (eg make a fist and thumbs-up twist it -twist it good.)
In combo with twist activated l.e. spoilers might even get a wingsuit that can... gasp...flare.

Now to get it to custom made stick to muscles for maximum usage of every muscle on bod just like real birdy. No wasted muscle usage equals ability to flap ie hold up body weight using all muscles not just tiny arm muscles.



we will work on it

just a question of time . . .

also rome wasn´t burned down in a day ;)
don´t pester the jester . . or better: WHY SO SERIOUS ? ?

www.pralle-zeiten.de

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Concerning videos of wing suit airflow, have you seen how airflow looks on our skydiving canopies?
I think many of you will be surprised - I was...



No, I haven't seen this, but I would be very curious about it. Do you happen to know if there is any video of this? In a similar way with threads as was done in the video I posted? Does the flow separation happen quickly too?

I see I stirred up a nice discussion with my post and video. :)
James, Robi, and Boris, (others?) do you have any video of similar experiments to see what happens with airflow over the wings on a wingsuit? The one video is only a small sample size of course, and I would like to be proven wrong about this.

Cheers,

Costyn
Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

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Biplanes, triplanes, multiplanes are inherently aerodynamically inefficient because of complex interactions between the two airfoils.
Beechcraft's Staggerwing was probably the best biplane, because they tailored the front/lower wing to IMPROVE airflow over the top/rear wing.
The other way to improve airflow over the rear wing is to increase separation ... great in theory, but structurally impractical on a wingsuit.

Which brings us to the primary reason biplanes worked so well in the early days of flying. Biplanes are extremely efficient structurally (strength to weight ratio), meaning that they can be built lighter than cantilever monoplanes. Try to think of a biplane as a very thick box beam. The beam webs are just flimsy combinations of struts and wires, that allow air to "leak" through.
Drag - from all those wires and struts does not become significant until around 100 knots.
Remember that the thicker the beam, the lighter you beam/wings you can build for the same strength.

In conclusion, biplanes worked great in the early days, because they allowed very light airframes. Light airframes can fly on tiny engines, etc.

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This actually gave me a thought:

Would it make sense that if the top/back surface of the wingsuit was as slick as possible, but the bottom surface had more of a directed pattern--like sharkskin--wouldn't the resulting difference in airspeed (between the air going over the back skin and the bellyskin) give us better lift? shit, if you did the top/back with the front 1/3 zp and rest f111 you'd even get the whole "suck the air over the top" thing going on...

am I just rambling, or does this make sense to anybody else?



>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>


A slick top skin helps reduce drag.
WE even hope that a slippery top skin will promote laminar flow farther back on the top skin.

However, I doubt if an exotic bottom skin/bellyskin would improve things much. At worst, it would only increase drag.

Your concept is the opposite of what most canopy manufacturers have done over the last decade.
Nowadays, most school (Skymaster, Solo, tandem, etc.) canopies are made with zero-porosity top skins and slightly porous (i.e. F-111) bottom skins. This is because a canopy "flies on its top skin. It is more complex than that, because air backing up also helps pressurize the bottom skin ...
Slightly porous fabric is used on bottom skins to make them easier to pack.

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James, Robi, and Boris, (others?) do you have any video of similar experiments to see what happens with airflow over the wings on a wingsuit?



Of course Phoenix-fly and Atair have it for wing suits and for canopies.
Any serious development will try to collect as many data as possible.

Boris

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