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# Wingsuit research

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platypii

MAGIC-FREE L/D

I mentioned in my earlier post that you don't need yuri's "magic" coefficients from WSE to compute L/D. Thought I would share the math here in case it helps someone's understanding of wingsuit dynamics.

The net acceleration A of a wingsuiter can be measured by GPS, and is equal to the sum of the force vectors: A = L + D + G

Split the equality into its vector components. The obvious thing would be to align our coordinates with earth (x and y axes), but that makes the math tricky. Much easier if we project it onto the Lift and Drag axes:

Rearrange to get:

Since we know the velocity components from GPS: sin(theta) = vy / v and cos(theta) = vx / v. Substitute to get:

Boom, L/D from GPS velocity and acceleration data! No magic

As a sanity check, when A = 0 it's easy to see that L/D = v_x / v_y = glide ratio. Exactly what we would expect for steady state flight. But this also works when accelerating.

This doesn't work if there is wind, because lift and drag forces will no longer be parallel and perpendicular to the velocity vector. But it works well in low-wind situations, especially BASE jumps.

Wonder if there will be more math skeptics...

Math looks good.

Edit: it wasn't good there was a sign messed up. Point being you can still calculate it using that formula once corrected.

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BTW, there's an error in signs, because if y axis points up (in WSE, it's down, so descent = positive Vy), then sin(theta) = -vy/v. The formula for L/D needs to be corrected. (I was checking it for ax=0, ay!=0 case and L/D was not equalizing with GR as it should).
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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yuri_base

BTW, there's an error in signs, because if y axis points up (in WSE, it's down, so descent = positive Vy), then sin(theta) = -vy/v. The formula for L/D needs to be corrected. (I was checking it for ax=0, ay!=0 case and L/D was not equalizing with GR as it should).

Yea working on an edit now, something looked wrong. In my defense, in baseline the formulas are implemented in 3D, and I had to re-do the math today for the 2D version.
BASEline - Wingsuit Flight Computer

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Here they are, in all their mess glory:

dVx/dt = g*V*[Kl*(Vx*Vy*cos(gamma) - Vz*V*sin(gamma))/sqrt(Vx^2+Vz^2) - Kd*Vx]

dVy/dt = g - g*V*[Kl*sqrt(Vx^2+Vz^2)*cos(gamma) + Kd*Vy]

dVz/dt = g*V*[Kl*(Vy*Vz*cos(gamma) + Vx*V*sin(gamma))/sqrt(Vx^2+Vz^2) - Kd*Vz]

Here Vx, Vy - as in WSE 2D, Vz - perpendicular to (Vx, Vy), and gamma is the bank angle.

Derived on 2009/09/27 on Zurich -> NYC flight (after a couple of beers, beer is the secret fuel of WS science!). Too lazy to post the full derivation, let alone the derivation of accelerometer-on-vane principle in 3D (it's several pages of nasty math), which still holds that L/D = g_|_ / g|| as long as turns are coordinated.
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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So given accelerations in X and Y, resolve the forces to tangent (D) and perpendicular (L) to the velocity vector in a uniform gravitational field, g.

Yes, you get:
L/D = (gVx-AyVx+AxVy)/(gV_y-VyAy-VxAx)

It's high school level mathematics.

How does this invalidate standard aerodynamic equations? How is this revolutionary? What other things do they say?

That was Yuri's claim. That's why I kept asking if his equations gave anything more than L/D, which he never answered. When I said they were wrong, it was because my definition of "flight" did not include completely ballistic trajectories, which this L/D includes (I still think it's silly, but it's just a matter of convention). So at least for this L/D equation, I take my statement back. (Yuri will of course start dancing and try to include me in his "religion", no thanks )

So in short, the "WSE" is a way to calculate accelerations given velocities, then resolving them in the "lift-drag" coordinate system. Not wrong, but not new, nor novel or groundbreaking.

But since Yuri's stopped insulting standard aerodynamics, I see no reason to keep arguing

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aonsquared

So given accelerations in X and Y, resolve the forces to tangent (D) and perpendicular (L) to the velocity vector in a uniform gravitational field, g.

Yes, you get:
L/D = (gVx-AyVx+AxVy)/(gV_y-VyAy-VxAx)

It's high school level mathematics.

Exactly. So, why don't we see it more, for example, in Paralog or Skyderby, after some wind subtraction? (I believe Skyderby has the wind subtraction feature.) It won't be perfect, since the wind can never be subtracted with reliable accuracy, but it's something better than just GR. L/D value at any time gives us the idea about current flight mode, like a slow flare with L/D slowly falling from 3.0 to 2.4 that was demonstrated in the analysis of someone's Paralog track, while GR by itself varies so wildly that it's virtually useless to look at it.

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How does this invalidate standard aerodynamic equations?

Which ones? Math, please, not English.

Quote

How is this revolutionary? What other things do they say?

It just happened that I dived into my mountains of old crap and digged out my old notes, yellowed out from age and covered with dust. Four Moleskine notebooks, peppered with equations, ideas, calculations - cover to cover. Many pages torn out of other notebooks with drawings and more formulas. It's daunting, depressing even - I literally need over 9000 years to process all this, write a book from it, make software out of it... Who can do all this?! I have to, this is my specialization, this where I should and will focus.

[inline Moleskins.jpg]

WSE and other math/physics related to wingsuits (or any glider for that matter) are fascinating, they are like [good] Pandora box filled with infinite amount of goodies. When I derived them in 2006, after months of staring at the same "high school level mathematics" and not seeing what was hiding in plain sight, I had such an "Eureka!" moment that I was literally levitating for a couple of years. (Like Archimedes jumped out of the bath naked and ran around town proclaiming his buoyancy law.) They are revolutionary, because they make so many things possible, literally magical things. I didn't call Kl, Kd "magic" coefficients of lift and drag; my company Pure Flying Magic (a variation of "pure fucking magic", as an answer to a question how some mysterious apparatus works); my app L/D Magic - for no reason. It's because WSE make magical things possible, like measuring L/D directly by accelerometer (and even bubble) - in real time, in any flight, sustained, nonsustained, 3D even; they make true Kalman filters possible, since WSE provide physical model of motion, as well as time evolution of other measurements, such as apparent gravity measured by accelerometer on a vane and on the body; they make flight analysis much more detailed and informative, vs. just current ground speeds and glide ratio; they make WS BASE flight modeling possible, for evaluating new, unopened flights (like Hartman does).

The algorithms for determining aerodynamics parameters I posted above are just maybe 0.1% of "What other things do they say".

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When I said they were wrong, it was because my definition of "flight" did not include completely ballistic trajectories, which this L/D includes (I still think it's silly, but it's just a matter of convention).

It's not silly, it's what we do on every WS BASE jump.

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So at least for this L/D equation, I take my statement back. (Yuri will of course start dancing and try to include me in his "religion", no thanks )

WSE # requires acceptance of WSE, not just the formula that relates L/D to GR and accelerations. So, WSE #5 remains vacant.

Quote

So in short, the "WSE" is a way to calculate accelerations given velocities, then resolving them in the "lift-drag" coordinate system.

No, WSE are these:

dVx/dt = g*V*(Kl*Vy - Kd*Vx)
dVy/dt = g - g*V*(Kl*Vx + Kd*Vy)

in 2D and see above for 3D. They are differential equations of motion, not "resolving them in the "lift-drag" coordinate system". The above derivation of L/D formula is a way of deriving it without WSE and "magic" Kl and Kd, although with WSE the derivation is much simpler, since all the steps with the force diagram and F=ma spelled out, are already encapsulated in WSE, no need to do them again. This is the symbolic math, this is how mathematicians and physicists operate, they derive equations and then reuse them, not start from the scratch every single time.

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Not wrong, but not new, nor novel or groundbreaking.

Saying "not wrong" about WSE qualifies one for WSE #. "Ladies and gentlemen, please welcome, WSE #5, aon squaaaaaaaaaaaaaaaaaaaaaared!!!"

Novel? Yes, absolutely. In more than 100 years of modern age aerodynamics, no text book or paper has WSE. (I'm urging anyone who disagrees to provide the proof. I've never seen them in many books and papers.) This is because nobody never needed them! Nobody in 100 years was interested to calculate the trajectory of a glider dropped from a huge cliff. People were always more interested in airplanes, and when they needed to do simulations of a glider flight (like Space Shuttle on landing, or NASA's lifting bodies) they had complete aerodynamics data from the tunnels, etc. - they could just integrate F=ma directly, using Cl, Cd, AoA, S, etc.

Nobody in more than 100 years needed WSE. So, I simply came, saw them hiding in plain sight, said to myself, "Nobody wants them? I'll take them!" BAM!!!

So, yeah, they are novel, and groundbreaking. Halle-fucking-luja!!!

Isn't it cool, that we, wingsuiters, have our own equations and theory? (even though WSE apply to any glider, and even no-lift body such as a cannon ball moving on ballistic trajectory, or a belly flyer/freeflyer jumping out of a plane)

Quote

But since Yuri's stopped insulting standard aerodynamics, I see no reason to keep arguing

Which insult to standard aerodynamics did I make? About splitting the total drag into parasite and induced? That's not an insult, I simply argue that this split is completely unnecessary for WS and makes weak minds get lost in a forest of two trees.

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He's finally looking at starting his own WS company, which I suggested to him in the first place and wish all the best of luck to!

OUR WS company, not mine. Our Wing Systems Blockchain Worldwide, ACME Wingsuits, call it whatever - the distributed, indestructible network of enthusiasts who are devoted to advancing wingsuiting to new levels, instead of passively waiting for The Stooges. Everyone is invited on board! Let us all, together, MWGA!
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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yuri_base

Which insult to standard aerodynamics did I make? About splitting the total drag into parasite and induced? That's not an insult, I simply argue that this split is completely unnecessary for WS and makes weak minds get lost in a forest of two trees.

We'll have to agree to disagree on the 'unnecessary' bit - if it's not useful to you, so be it. I shall now get back to my own work and stop arguing Carry on!

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aonsquared

I shall now get back to my own work

Drop it! WSB needs workforce, lots of it! Aerospace engineers are especially welcome. Any smart people are welcome. We're "hiring"!

Altimeters are so 20th century, we need flight computers, and not just this lame thing called GPS (I wouldn't call GPS a flight computer, it's a flight confuser), with ground speed and glide ratio, that's just too trivial and virtually useless. An aerospace engineer, teamed with a mechanical engineer, teamed with a physicist/programmer, can make a nice, slick, sexy WS instrumentation possible. And it doesn't need a company, we all at WSB can contribute, and make it a professionally looking, DIY, 3D-printable device (not my ugly vane of poor workmanship). (But as always, anyone who wants to do it commercially, just do it! WSB is total freedom and doesn't restrict any commercial spin-offs.)
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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I hope I can skydive and BASE jump for at least 20 more years, but judging by the 13 years of wingsuiting/BASE I personally witnessed, there's not much progress happened and if the state of CoW continues through the year 2038+, in 2040's we'll see same T-mattresses, just more gimmicks, maybe a couple of more pockets and color patterns, and zippers that are also patterned, not just solid color. Wingsuit prices will hike up to \$4000, and the suits will be made so flimsy that they will literally fall apart after one season. The competition window will be decreased to 100m, and with glide ratios of 20 or more in the window, it will be touted as if amazing progress has been achieved... (but L/D will remain the same 3.0 as today.) There will be WS "instrumentation" - a mobile device that allows checking Facegramitter likes in flight, that's all "data" people will be interested in.

That's the grim future we gonna see in 20 years if we continue worshipping our Stooges.

*We* need to change this. The Stooges won't change by themselves.

Wing Systems Blockchain, WS Revolution of 2018 for the win!

MWGA!!!
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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On an unrelated note what notebooks are those? They look nice.

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Moleskine
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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Sorry But my suggestion is to look at flow separation - it happens really early on wingsuits, creating lots of extra drag and wasting that extra surface area. Somehow find a way to keep that boundary layer attached, and you can cut drag way down. Keep lift the same, and your L/D will shoot up :)

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aonsquared

Sorry But my suggestion is to look at flow separation - it happens really early on wingsuits, creating lots of extra drag and wasting that extra surface area. Somehow find a way to keep that boundary layer attached, and you can cut drag way down. Keep lift the same, and your L/D will shoot up :)

I would be curious to see what would happen if they made a suit out of sail cloth like HP canopies.

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LeeroyJenkins

***Sorry But my suggestion is to look at flow separation - it happens really early on wingsuits, creating lots of extra drag and wasting that extra surface area. Somehow find a way to keep that boundary layer attached, and you can cut drag way down. Keep lift the same, and your L/D will shoot up :)

I would be curious to see what would happen if they made a suit out of sail cloth like HP canopies.

I'm no expert here, but for me it seems that the material used for wingsuits (at least SQ, but I think PF uses now something very similar) is thicker and in my opinion would be more rigid than sail.

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skow

******Sorry But my suggestion is to look at flow separation - it happens really early on wingsuits, creating lots of extra drag and wasting that extra surface area. Somehow find a way to keep that boundary layer attached, and you can cut drag way down. Keep lift the same, and your L/D will shoot up :)

I would be curious to see what would happen if they made a suit out of sail cloth like HP canopies.

I'm no expert here, but for me it seems that the material used for wingsuits (at least SQ, but I think PF uses now something very similar) is thicker and in my opinion would be more rigid than sail.

I've never closely compared the two, I suspect sail cloth is smoother, it may however need more reenforcement to stay in shape.

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aonsquared

my suggestion is to look at flow separation - it happens really early on wingsuits, creating lots of extra drag and wasting that extra surface area. Somehow find a way to keep that boundary layer attached, and you can cut drag way down. Keep lift the same, and your L/D will shoot up :)

Yes, but how? I think this is where the idea of placing the body at zero AoA and having non-zero AoI for the wings could probably shine (it's unproven so far, though). I did some estimates, and it seemed to be feasible.

[inline ZeroBodyAoA.jpg]

This picture is not exactly what I have in mind: upper legs should be bent a bit at the hips, but lower legs should be parallel to torso, so both torso and lower legs are at zero AoA, wings are at non-zero AoA (equal to AoI in this case).

The airflow above torso will be then much smoother, since it's essentially in "headdown", or "speed skydiving" position to relative wind, and the drag should be greatly reduced. And is argued in the calculations above, the loss of drag will be advantageous despite loss of lift from the body, since body has such poor L/D by itself (0.7-1.0).

PS. Legs should be like in this picture of atmonauti (the top jumper): bent in hips, but lower legs parallel to airflow. Torso is also parallel to airflow (the very idea of atmonauti). Does anyone even do atmonauti these days anymore?...

[inline Atmonauti.jpg]
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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yuri_base

***my suggestion is to look at flow separation - it happens really early on wingsuits, creating lots of extra drag and wasting that extra surface area. Somehow find a way to keep that boundary layer attached, and you can cut drag way down. Keep lift the same, and your L/D will shoot up :)

Yes, but how? I think this is where the idea of placing the body at zero AoA and having non-zero AoI for the wings could probably shine (it's unproven so far, though). I did some estimates, and it seemed to be feasible.

This picture is not exactly what I have in mind: upper legs should be bent a bit at the hips, but lower legs should be parallel to torso, so both torso and lower legs are at zero AoA, wings are at non-zero AoA (equal to AoI in this case).

The airflow above torso will be then much smoother, since it's essentially in "headdown", or "speed skydiving" position to relative wind, and the drag should be greatly reduced. And is argued in the calculations above, the loss of drag will be advantageous despite loss of lift from the body, since body has such poor L/D by itself (0.7-1.0).

PS. Legs should be like in this picture of atmonauti (the top jumper): bent in hips, but lower legs parallel to airflow. Torso is also parallel to airflow (the very idea of atmonauti). Does anyone even do atmonauti these days anymore?...

Just fyi in high speed comps the suit is flying closer to your "super terminal" image.

Also air flow separation is more attributed to material than it is to anything else. The better change the boundary layer has of "sticking the longer it will stay attached" Its the concept behind vortex generators. By keeping that layer as small and attached for as long as possible lift will be increased.

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Found some old sketches back from 2008. These are very rudimentary and messy, but I hope they are sufficient to give one the general idea. I hope someone will like the idea and start working on this, as I simply cannot do everything myself, I have so much work to do in WS theory and software, I better focus on those.

The goal is to build the highest L/D wingsuit (wing system) in the world, in human history. The goal is to make it DIY, so anyone with even basic DIY skills can build one for themselves. The goal is to make it affordable, with bill of materials in \$100-200 range. The goal is to make it modular, so that different arm and leg wings (different airfoil profile, planform, thickness, etc.) can be installed on the same belly and leg platforms. The goal is to make it adjustable, so that basic parameters like AoI, trim/balance can be adjusted between the jumps. The goal is to stop sewing costumes, and start engineering flying machines. The goal is to make it open source, so that anyone in the world (every WSB 'employee') can make a contribution, or branch off, or even go commercial and make money, if they want. The goal is freedom from the state of CoW, from The Stooges, from 20 years of The Great Stagnation.

"Every once in a while, a revolutionary product comes along that changes everything. Well, today, we’re introducing three revolutionary products.

The first one: is a DIY, open source wingsuit.
The second: is a revolutionary modular wing system.
And the third is a breakthrough experimental platform.

So, three things: a DIY, open source wingsuit; a revolutionary modular wing system; and a breakthrough experimental platform.
A DIY wingsuit, a modular wing system, and an experimental platform. A DIY wingsuit, a modular wing system … are you getting it?

These are not three separate devices, this is one device, and we are calling it THE MACHINE.
Today Wing Systems Blockchain is going to reinvent the wingsuit, and here it is."

- this is just for a laugh, a flashback to Steve Jobs' introduction of iphone, but who knows, maybe this, not mattresses, will become the platform of the future?... Let's do it! Everybody, welcome to THE MACHINE!!!

Welcome my son, welcome to THE MACHINE
Where have you been?
It's alright we know where you've been
You've been in the pipeline, filling in time
Provided with toys and 'scouting for boys'
You brought a guitar to punish your ma
And you didn't like school, and you
Know you're nobody's fool
So welcome to THE MACHINE

1. Body at zero AoA, arm wings at non-zero AoI; same with leg wing, which starts from knees down, with distinct leading edge; upper legs bent at hips, but not as much as in the pic, maybe about 30 degrees.

[inline TheMachineSketch2008-1.jpg]

2. Some dimension and planform prototyping.

[inline TheMachineSketch2008-2.jpg]

3. Foam (PU foam, high-resilience, "blue foam", "lux high quality foam") needs to be about 5" for the arms. Liebeck high-lift airfoil is used, with 25% thickness. Foam is not cheap for individual purchase, but for 80 or so bucks you get approx. twin-sized "mattress", enough for complete wing system.

[inline TheMachineSketch2008-3.jpg]

4. Leg wing has trapezoid shape, these dimensions make a small wing, but it can be made bigger.

[inline TheMachineSketch2008-4.jpg]

5. Arm wing sample dimensions.

[inline TheMachineSketch2008-5.jpg]

6. Arm wing dimensions and the elliptical cut out to for the arm.

[inline TheMachineSketch2008-6.jpg]

7. Liebeck airfoil profile at the root of the arm wing and at the tip.

[inline TheMachineSketch2008-7.jpg]

8. Arm wing channel, leading edge and trailing edge with possible stiffeners.

[inline TheMachineSketch2008-8.jpg]

All this is, of course, very raw, just sketches, is as far from a finished product as it could be. But I hope someone will find this useful and start working on building something like this.

The most difficult parts, I think, are wing attachment platforms (that are attached to belly and lower legs with adjustable belts, and then wings attach to those with some kind of quick connection, with adjustable AoI) and arm wing's arm channel and ability to free arms using a zipper, yet not affecting the precise airfoil shape of it. "Hiring" genius mechanical engineers! "Hiring" anyone smart! Everyone is welcome... welcome to The Machine!

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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Forgot: WSE can (and should!) be used in wingsuit simulation games. I've seen some code of those and it's... terrible 'physics', having nothing to do with reality. Just step-wise incrementing speed according to inputs, with arbitrary parameters, and calculating new position. (like, if player pushes up button to make pitch steeper, increase speed by 1mph per click) Even in those games that seem to be more realistic, such as "volo sport" (I forgot exact name, I think it was even discussed in this forum a bit) the physics is just not right. WSE 3D will make realism mind blowing, and the simulator can be used for evaluating potential exit points!
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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One thing I will say is that you are persistent, maybe a little nuts, and dedicated.

What you want to build is not a main stream wingsuit. You want something highly specialized that will not be commonly used and for sure will not be used in small planes.

Stop fighting with the MSWM or whatever you call them and focus on the custom suits

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LeeroyJenkins

***

I'm no expert here, but for me it seems that the material used for wingsuits (at least SQ, but I think PF uses now something very similar) is thicker and in my opinion would be more rigid than sail.

I've never closely compared the two, I suspect sail cloth is smoother, it may however need more reenforcement to stay in shape.

If I'm not mistaken, isn't PF's baloon fabric (not sure if used anymore) a thicker version of sail?

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LeeroyJenkins

What you want to build is not a main stream wingsuit. You want something highly specialized that will not be commonly used and for sure will not be used in small planes.

Yes, it won't be a mainstream wingsuit, but it doesn't need to be. It's in addition to mattresses. What we have now is like a minivan - it does the job done, drive kids to school, drive to a mall, it's roomy and reliable, can even go high performance:

[inline Minivan.png]

But if we don't do anything, we'll never get this additional toy in our garage:

[inline SportsCar.jpg]

Mattress = minivan
'The Machine' = sports car

We need both! Mattresses are not going anywhere. Right tool for the right job! But if all we see in the year 2038, another 20 years from now, is mattresses/minivans, it's just a lame waste of time and talent we all collectively have.

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Stop fighting with the MSWM or whatever you call them and focus on the custom suits

Good call for all of us in our distributed global network of revolutionaries! Wingsuit "bitcoin miners", let's roll up our sleeves and actually do it! Exposing mainstream WSMs (aka 'The Stooges') was only necessary to start the Great Wingsuit Revolution of 2018, but they are irrelevant now as they have a proven track of not coming up with anything new in decades. Let's MWGA! Our future is in our hands.
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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yuri_base

***What you want to build is not a main stream wingsuit. You want something highly specialized that will not be commonly used and for sure will not be used in small planes.

Yes, it won't be a mainstream wingsuit, but it doesn't need to be. It's in addition to mattresses. What we have now is like a minivan - it does the job done, drive kids to school, drive to a mall, it's roomy and reliable, can even go high performance:

But if we don't do anything, we'll never get this additional toy in our garage:

Mattress = minivan
'The Machine' = sports car

We need both! Mattresses are not going anywhere. Right tool for the right job! But if all we see in the year 2038, another 20 years from now, is mattresses/minivans, it's just a lame waste of time and talent we all collectively have.

Quote

Stop fighting with the MSWM or whatever you call them and focus on the custom suits

Good call for all of us in our distributed global network of revolutionaries! Wingsuit "bitcoin miners", let's roll up our sleeves and actually do it! Exposing mainstream WSMs (aka 'The Stooges') was only necessary to start the Great Wingsuit Revolution of 2018, but they are irrelevant now as they have a proven track of not coming up with anything new in decades. Let's MWGA! Our future is in our hands.

Lol, no. They were not exposed for being anything. They product a good product that has been taking incremental steps.

What you want is something closer to Jetman, and to a modern wingsuit.

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As my 'starter fluid' was being topped off, I found this old idea I totally forgot about: how to measure L/D on the ground, either with real wingsuit/pilot, or a scaled experimental model - all without a wind tunnel!

[inline LDMeasurementWithoutWindtunnel.jpg]

Imagine a WS model suspended from a balance scale, precisely balanced with counterweight, outside on a windy enough day. The model is held in place by horizontal rope as to keep the suspension cable vertical. Then, rope is released. What will happen? Aerodynamic force (with lift and drag components) will push the model at some angle up from equilibrium state. As shown, horizontal and vertical accelerations in the first moments after release will be

ax = g*(D/W)
ay = g*(L/2W)

(this assumes that scales' arm weighs negligibly little compared to model; if it can't be neglected, then the factor 2 will be replaced by a bigger factor that takes both extra weight and moment of inertia; or instead of balance scale, a lightweight pulley can be used as pictured on the left of the scales)

So if we measure these accelerations with a smartphone's accelerometer, we can find out L/D!

L/D = 2ay/ax

If we're only interested in measuring L/D, even accelerometer is not necessary - since ratio ay/ax is equal to the tangent of the angle alpha of initial movement to vertical,

L/D = 2*tan(alpha)

We can also find out absolute values for lift and drag, if weight is known:

L = 2W*(ay/g)
D = W*(ax/g)

And, if we measure wind speed with an anemometer, we can find out Kl, Kd:

Kl = L/V^2
Kd = D/V^2

And from these, sustained horizontal and vertical speeds for this flight mode:

Vxs = Kl/(Kl^2 + Kd^2)^(3/4)
Vys = Kd/(Kl^2 + Kd^2)^(3/4)

And these, for different AoA, will form the polar curve!

How cool is that?! We can do fast-iteration wingsuit improvements right on the ground, and without making rich richer at \$1000/hour! All you need is to build a balance that can support the model or even the pilot, and probably ~20mph wind should suffice.

A model can be built using modeling clay and armature like this one:

[inline ModelingArmature.jpg]

With polymer clay, the shape of wings, angles of incidence, body position, etc. can easily be adjusted and studied.

Or, 3D-print a model, make it from several parts and connect them with adjustable armature.

MWGA!

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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A couple of additional illustrations to show the proper body position and wing angles. Very much like atmonauti, so maybe we can call it "wingmonauti"?

"Lucifer's Dream" was the original name of the wing system, because it had my favorite letters, L and D in it, so I could play this out; but now I like 'The Machine' better. Engineered, not sewed; precise, efficient, fast, lean & mean... true machine!

Nature's beauty and wingsuit science go well together, because wingsuit science is beautiful:

[inline TheMachineSketch2008-9.jpg]

[inline TheMachineSketch2008-10.jpg]

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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