Wingsuit research

First constructive comment in this thread, much appreciated!

platypii

what are your concrete suggestions to WS manufacturers? If you had a factory for a day what would you build?

1. Explore putting the body at zero AoA (like airplane's fuselage) and varying AoI (angle of incidence) of both arm and leg wings (requires separate arm/leg wings, like in old style suits, and leading edge on the leg wing, like Vampire series). Make several suits with 5 degree increment in AoI, study their max L/D using, for example, L/D Vario on a vane. The pilot, of course, needs to learn new style of flying, where the body is in line with the airflow, creating minimal drag and zero lift (all lift is generated by wings only). The idea is (like in airplanes) to exclude the very inefficient generator of lift - body/fuselage - as much as possibly, leaving pretty much only its cross-sectional drag.

[inline 1.jpg]

2. Explore a sealed, weakly inflated (just a bit above dynamic pressure in flight) shaped leading edge made of rubber (like a bike inner tube, but profiled), with significantly more forward extension (3 inches?) than current foam inserts, yet having minimal force added for pull, etc. In attempt to make a really nice airfoil profile, not what we have now with big radius of curvature on the leading edge, which creates a lot of drag. Quantify the improvements with L/D Vario.

3. Combine 1&2. Quantify the improvements with L/D Vario.

4. Make a wingsuit with foam wings (closed cell polyurethane foam like one used in cushions, etc.) This will eliminate the need for inflation and big scoops creating drag. I've started making a prototype long time ago (2010-ish) but haven't finished and haven't flown it (the leg wing was almost done, but I don't have it with me now to post a picture). The foam is easily foldable, so the pull should not be more difficult than with regular suits. The foam wing will maintain the airfoil shape more precisely than inflated fabric can. (Also, possibly to try stepped airfoil.) The leg wing should have a large leading edge (i.e. it should start in the knee area) to maximize its efficiency, not just be a surface where de-energized, turbulent air rolls over it. The wings should have a non-zero AoI as in #1. Better yet, make wing attachment with adjustable AoI (on the ground, not dynamically in the air). Quantify the improvements with L/D Vario.

5. Superman's half-wingsuits (leg wing only). Flying with arm(s) stretched forward, or in regular tracking position. Need to fine tune the trim/balance, since with my half-V-4 stretching arms forward was producing too much "front momentum" (not enough momentum from the leg wing). Quantify the improvements with L/D Vario, compared to tracksuits. Quantify max horizontal speed and set a new world record, leaving full wingsuits in the dust! (since it's naturally close to L/D=1.4 and lacks extra fabric of full wingsuit which at this L/D is only a burden)

6. In A/B tests, quantify the effects of [in my opinion, gimmicks] innie-outie, cross-hatched fabric (?) on the bottom surface of arm wings, rubber-like leading edge material. Remove them if they, indeed, turn to be just gimmicks ("this material is used in space shuttle!" type of BS)

7. Quantify effects of various elements on max L/D, just to know, how much of a bite each is taking off the absolute max performance: helmets, cameras, shoes with flaring out soles (like on most sneakers), various rigs.

8. Study the effect of increasing surface area on L/D to see if the curve (L/D) vs. S shows an asymptotic slowdown or there's still some potential.

9. Make a gigantic suit similar to Antoine Laporte's and measure its max L/D precisely.

10. Make goal-specific wingsuits for speed, time, and distance rounds in competitions. The slowest (in fall rate) wingsuits will be amazing for BASE starts! (will be almost a ground launch). A giant suit with ridiculously thick airfoil. For speed, probably Superman's half-suit. For distance, probably #1 or #4. Let the pilots use 3 different suits in competitions! In triathlon, they don't require athletes to run and swim while carrying their bicycle, do they? Each round requires a specific tool, why not in wingsuit competitions?

11. Make a compact, low drag air intake on the helmet or short tubes protruding from armwings, with the delivery of ram air into wings via flexible tubing, to eliminate large draggy scoops altogether.

12. Overall, explore the old split-wings designs more, since no scientific study like this has been done in their era in early 2000's. I believe they still have the potential if we're made to look like little airplanes, rather than mattressy squirrels.

Should be plenty for a day...

platypii

Proper aerodynamic instrumentation would be great, because GPS is useless when comparing between different skydives. But does it offer anything over flying next to someone? My understanding is that WS manufacturers do iterative development by flying next to people they fly with all the time, and see what effects are of suit changes. By flying relative to another person, the wind effects are irrelevant, and you can see if you can edge ahead of them, or out float them.

No, I don't think so. People are different, differences between them and the variations in flying of the "reference" pilot are not as precisely quantifiable as aerodynamic instrumentation. In aviation, they study planes with instrumentation, not flying relative to another plane. Dynamic effects (slow planeout/flare) also cannot be excluded (while L/D Vario excludes it in real time, since L/D measured by accelerometer is not affected by "fake" changes in glide ratio).

platypii

Based on your models, do you think we should be working more on increasing lift (surface area)? Or more work on decreasing drag? How do the wingsuit equations help inform which changes to try?

WSE cannot say which one to work more on, lift or drag. As "magic" L/D's show (1.414, 2.61, 3.567), the dynamic behavior of gliders does not depend on the nature or their absolute lift or drag, only on their ratio, L/D. For example, sqrt(2) as the L/D for max horizontal speed, applies to both wingsuits and canopies or other gliders (hang-, para-). As mentioned before, L/D is like a reverse of coefficient of friction, one should make coefficient of friction lower. So, we should always strive to increase L/D by all means, even if it means decreasing lift, but decreasing drag even more so that L/D grows.

I think that airplane-like planform, with proper AoI and wide leading edge on the leg wing (much wider than on Vampires) still has a healthy unexplored potential. The mattresses reached L/D=3.0, in my opinion, purely by dumbly increasing surface area which makes the negative contribution from the body in overall performance less noticeable (like diluting very salty water with clean water makes it less salty).

platypii

***The best competition pilots are able to do 4:1 and THAT is proven in the field actually by raw data, not by only talking about formulars. Where? At world championships for years. Because some distance runs in these comp's are not done in downwind, but in crosswind well more or less (now the math genius attacks). I have noticed that 4:1 is achievable but off course that is not proof to math genius.

Disagree. Performance comps are all about the setup dive and energy management (aka- long slow flare). Also really hard to say with any certainty the effect of the winds. Based on all the data I've seen, and I've seen a lot, I think wingsuits are BARELY above 3:1 L/D.

This.

Here's a little handy trick that follows from WSE: first, estimate the wind from the meteorological data and vector-subtract it. Next, on the horizontal speed graph (which now will be at least better representing the true airspeed) locate the points where Vx goes through a minimum, maximum, or has an inflection point with zero derivative. At these points, the air glide ratio is equal to L/D.

You will see that it's never ever greater than 3.0.

(I wouldn't recommend Paralog for this, though, since it seems to be using some kind of smoothing that produces oscillations which can be mistakenly taken for extrema.)

L/D, unlike glide ratio (either ground or even air), has a very strict ceiling. No one can break through this ceiling no matter what dives, flares, etc. they're doing. GR can be anything - from 0 to +infinity to -infinity to some negative number (steepest angle going up in flare). L/D for current state of wingsuiting, is topped at approx. 3.0 with normal rig and normal body build.

Dude, there are so many things wrong with your post it would take forever to correct them all.

Wingsuit specifically, it seems like you aren't aware there are different kids of suits for speed and distance compititions.... there are.


You also never answered my question, what is the number 1 limiting factor in wingsuit design?

I know, I actually fly at these competitions still, last one World Champs in Prostejov. What I am talking about is not glide including the energy coming from the flare... It is the sustained glide, after the flare energy has been used out. The scoring software we use not only records and displayes this, it also records the wind factor that day aloft. So yes we have this data, and how refreshing this is instead of peoples blablabla

birdynamnam

It is the sustained glide, after the flare energy has been used out. The scoring software we use not only records and displayes this, it also records the wind factor that day aloft. So yes we have this data, and how refreshing this is instead of peoples blablabla

Where's the graph?

yuri_base

***It is the sustained glide, after the flare energy has been used out. The scoring software we use not only records and displayes this, it also records the wind factor that day aloft. So yes we have this data, and how refreshing this is instead of peoples blablabla

Where's the graph?

Don't dodge the question. What is the number one limiting factor in wingsuit design?

birdynamnam

What Yuri says about glide ratio 3:1 is not true at all. The best competition pilots are able to do 4:1 and THAT is proven in the field actually by raw data, not by only talking about formulars. Where? At world championships for years. Because some distance runs in these comp's are not done in downwind, but in crosswind well more or less (now the math genius attacks). I have noticed that 4:1 is achievable but off course that is not proof to math genius.

I'll show how it's done.

Let's take this track from Paralog as an example.

https://www.paralog.net/ppc/showtrack.php?track=26916

[inline FritsJensen1.png]

In 3D view,

https://www.paralog.net/ppc/showtrack3D.php?track=26916

[inline FritsJensen2.jpg]

we see that the flight is pretty much exactly downwind, with the wind of 49km/h (26.6kn) right on the back (257 degrees).

So, we subtract 49km/h from horizontal speed.

Let's use the above mentioned WSE trick to find L/D in extrema points of Vx (in these points, according to WSE, L/D is equal to air glide ratio; in arbitrary point, L/D != GR).

We see several minima/maxima in Vx:

t=33.0s, Vx=146, Vy=48, L/D = 3.04, ground GR = 4.06
t=42.0s, Vx=151, Vy=53, L/D = 2.85, ground GR = 3.77
t=59.0s, Vx=130, Vy=49, L/D = 2.65, ground GR = 3.65
t=74.4s, Vx=132, Vy=51, L/D = 2.59, ground GR = 3.55
t=87.0s, Vx=122, Vy=50, L/D = 2.44, ground GR = 3.42

So we can clearly see that this is nothing but gaining tremendous speed before the window and slowly (very slowly) flaring it into a better GR. L/D starts from 3.04 and continuously falls down - the angle of attack is slowly increased, L/D is decreasing. Average GR in the window - 4.195, but this is not L/D! L/D is 3.04 max.

We can analyze any Paralog or Skyderby track like this and see that max L/D is never higher than 3.0 (plus/minus small change).

Besides using extrema points, one can use general formula that relates L/D and GR, which is derived from WSE:

L/D = (GR + z)/(1 - GR*z)

where z is dimensionless ratio z = ax/(g - ay), ax is horizontal acceleration, ay vertical, g acceleration due to gravity. GR here is glide ratio relative to air, not ground! Also, when z = 0, L/D = GR, as mentioned above. Also, whenever you're decelerating (even very slowly!), z is negative, and so GR is automatically higher than L/D. This is the principle of all these competitions - slow deceleration in competition window after a massive dive, deceleration gives high GR (distance round) or slower descent rate (time).

L/D is like a inverse of coefficient of friction: the latter depends only on smoothness of surfaces and has a finite minimum value (coeff. of friction can never be zero, excluding quantum phenomena like superfluidity). Same with L/D - it's a finite value from 0 to (for current wingsuits) 3.0 (+/- maybe hundredths). No one can fly current wingsuits with L/D higher than this max value! Glide ratio is a different animal altogether, it can be anything from -infinity to +infinity. Same as a skateboard temporarily moving horizontally or going up - it doesn't mean the coefficient of friction turned zero or became negative!

L/D is a true aerodynamic finesse parameter, GR is for these bogus competitions with their bogus numbers (5:1, 6:1, etc.)

L/D for the win!!!

yuri_base

***What Yuri says about glide ratio 3:1 is not true at all. The best competition pilots are able to do 4:1 and THAT is proven in the field actually by raw data, not by only talking about formulars. Where? At world championships for years. Because some distance runs in these comp's are not done in downwind, but in crosswind well more or less (now the math genius attacks). I have noticed that 4:1 is achievable but off course that is not proof to math genius.

I'll show how it's done.

Let's take this track from Paralog as an example.

https://www.paralog.net/ppc/showtrack.php?track=26916

In 3D view,

https://www.paralog.net/ppc/showtrack3D.php?track=26916

we see that the flight is pretty much exactly downwind, with the wind of 49km/h (26.6kn) right on the back (257 degrees).

So, we subtract 49km/h from horizontal speed.

Let's use the above mentioned WSE trick to find L/D in extrema points of Vx (in these points, according to WSE, L/D is equal to air glide ratio; in arbitrary point, L/D != GR).

We see several minima/maxima in Vx:

t=33.0s, Vx=146, Vy=48, L/D = 3.04, ground GR = 4.06
t=42.0s, Vx=151, Vy=53, L/D = 2.85, ground GR = 3.77
t=59.0s, Vx=130, Vy=49, L/D = 2.65, ground GR = 3.65
t=74.4s, Vx=132, Vy=51, L/D = 2.59, ground GR = 3.55
t=87.0s, Vx=122, Vy=50, L/D = 2.44, ground GR = 3.42

So we can clearly see that this is nothing but gaining tremendous speed before the window and slowly (very slowly) flaring it into a better GR. L/D starts from 3.04 and continuously falls down - the angle of attack is slowly increased, L/D is decreasing. Average GR in the window - 4.195, but this is not L/D! L/D is 3.04 max.

We can analyze any Paralog or Skyderby track like this and see that max L/D is never higher than 3.0 (plus/minus small change).

Besides using extrema points, one can use general formula that relates L/D and GR, which is derived from WSE:

L/D = (GR + z)/(1 - GR*z)

where z is dimensionless ratio z = ax/(g - ay), ax is horizontal acceleration, ay vertical, g acceleration due to gravity. GR here is glide ratio relative to air, not ground! Also, when z = 0, L/D = GR, as mentioned above.

L/D is like a inverse of coefficient of friction: the latter depends only on smoothness of surfaces and has a finite minimum value (coeff. of friction can never be zero, excluding quantum phenomena like superfluidity). Same with L/D - it's a finite value from 0 to (for current wingsuits) 3.0 (+/- maybe hundredths). No one can fly current wingsuits with L/D higher than this max value! Glide ratio is a different animal altogether, it can be anything from -infinity to +infinity. Same as a skateboard temporarily moving horizontally or going up - it doesn't mean the coefficient of friction turned zero or became negative!

L/D is a true aerodynamic finesse parameter, GR is for these bogus competitions with their bogus numbers (5:1, 6:1, etc.)

L/D for the win!!!

Did you just use your own equations to prove your equations right?

Also, everyone note, the reason yuri wont answer my question about the limits of wingsuit design is because he knows it will ruin his own argument (or he actually doesn't know) which would be ridiculous since he is claiming to have this revolutionary knowledge.

yuri_base

We can analyze any Paralog or Skyderby track like this and see that max L/D is never higher than 3.0 (plus/minus small change).

I must correct myself. Some tracks, if this procedure with wind subtraction and Vx extrema is performed, result in values higher than 3.0 - for example, this track has 3.33 at 42.8s and even 3.48 at 60.8s.

To me, it only indicates one thing: the wind profile cannot be known with accuracy needed to precisely measure L/D on a skydive with GPS. GPS is not an L/D tool at all. It's a ground track tool, not an aerodynamic tool.

The only right way to measure L/D is with a vane, period. Or with a Pitot tube which also must be on a vane, far from the body.

hey mr.Yuri, your long posts look really nice, I see you put a lot of work into this. But please, can you answer this question with a simple yes or no:

Did you just use your own equations to prove your equations right?

thank you

Haha I suck at distance use this one instead https://ppc.paralog.net/showtrack.php?track=26136

birdynamnam

Haha I suck at distance use this one instead https://ppc.paralog.net/showtrack.php?track=26136

5.0km

How about this one?

https://ppc.paralog.net/showtrack.php?track=20949

2.3km

Same pilot, same suit.

Why the huge difference (more than 2x)? Pilot's bad day? Nope. WIND. Apparently, at Zephyrhills the rules of the DZ mandated the jump run in certain direction which forced pilots to fly against the wind. Hence, the huge difference between horizontal speeds (e.g. 216km/h and 86km/h). So, if in Overton the actual wind, for example, was +65km/h (tailwind), and in ZH it was -65km/h (headwind), it explains the huge 130km/h difference. (The wind numbers that can be seen on some tracks in PPC are useless, nobody can know the exact wind profile at the time of the jump, the only way to measure it is to launch a weather balloon right in the place and time of each jump.)

This shows that Paralog graphs are completely useless in determining the state of the art L/D of modern wingsuits. Moreover, it's not only "passively" useless, it's "actively" misleading, as the graphs create this aura of "scientificity" which misleads naive people, including PPC pilots themselves. That's how these legends of "4:1" or "3.5:1" are born - from lack of being critically analytic with data.

GPS is garbage and should never be used other than a recorder of coordinates (for example, to show the flight line in WS BASE). All these horizontal (and even vertical, when there are thermals like in BASE) speeds and ground glide ratios are completely useless and misleading in determining the aerodynamic parameters of the wingsuits.

When a pilot only knows GPS/Flysight, it just shows total lack of technical understanding of the problem. It's hopeless to explain anything to them, they are in the state of... CoW.

Vane is the only means to completely exclude winds and thermals. L/D Magic, launched to Apple app store in May 2013, for 5 years remains the first and the only full aerodynamic measurement device (L/D, air GR, Vx, Vy, Vxs, Vys, Cl, Cd, L, D) in Solar System to date, while the freely available L/D Vario launched 3 years ago is a much simplified version of it (without Kalman filters, which eliminates the requirement to jump at precise moment, it works continuously). But nobody ever jumped with a vane, other than myself. (Not bragging, rather disappointed.) Even WSMs (!), although they should be the first to embrace this technology.

The rubber band of disparity between available technology and Amish-like resentment of The Three Stooges to truly scientific methods continues to stretch for 5, 10, 12 years now. When it's going to rupture? The situation is nothing but comic now. Will they be honest and put this fact in Wikipedia article about wingsuits? *(The answer is below.)











* Not a chance.

I proved Wingsuit Equations in 2006, see OP for the link.

Now, in modern civilized countries, there's this principle,

https://en.wikipedia.org/wiki/Presumption_of_innocence

Quote

ei incumbit probatio qui dicit, non qui negat (“the burden of proof is on the one who declares, not on one who denies”)

So anyone who thinks that WSE and related math I derived is wrong, has a burden to rigorously, mathematically - not by just blah-blah-blah - prove that they are wrong.

However, as noted in Wikipedia,

Quote

Middle Ages in Europe: After the fall of the Roman Empire, Europe fell back on feudal law. This included some Germanic customs, including presumed guilt.

I guess, there are people still thinking in feudal law terms.

The first here who will rigorously, mathematically - not by just blah-blah-blah - prove that Wingsuit Equations are wrong, will receive the unofficial Nobel Prize in Wingsuit Science (and probably, the official one in Physics, presented by the King of Sweden in Stockholm, for proving Newton's F=ma wrong, since WSE is nothing but F=ma as applied to wingsuits).

yuri_base

I proved Wingsuit Equations in 2006, see OP for the link.

Now, in modern civilized countries, there's this principle,

https://en.wikipedia.org/wiki/Presumption_of_innocence

Quote

ei incumbit probatio qui dicit, non qui negat (“the burden of proof is on the one who declares, not on one who denies”)

So anyone who thinks that WSE and related math I derived is wrong, has a burden to rigorously, mathematically - not by just blah-blah-blah - prove that they are wrong.

However, as noted in Wikipedia,

***Middle Ages in Europe: After the fall of the Roman Empire, Europe fell back on feudal law. This included some Germanic customs, including presumed guilt.

I guess, there are people still thinking in feudal law terms.

The first here who will rigorously, mathematically - not by just blah-blah-blah - prove that Wingsuit Equations are wrong, will receive the unofficial Nobel Prize in Wingsuit Science (and probably, the official one in Physics, presented by the King of Sweden in Stockholm, for proving Newton's F=ma wrong, since WSE is nothing but F=ma as applied to wingsuits).

In simpler words. Yes he used his own equations to prove that his equations are right.

I've read the works of early aerodynamicists: Otto Lilienthal (1889), Nikolai Zhukovsky (1891) on unpowered bird or glider dynamics; many aerodynamics books (either read or skimmed specifically in search for WSE analog) - and never found anything resembling WSE. If unpowered flight is considered in a book, it's only dealing with parameters like AoA, Cl, Cd, surface area, etc. - exactly what the trick of WSE manages to avoid completely, since we don't know these parameters. The trick of WSE is to hide these parameters into "magic" coefficients of lift and drag, Kl and Kd, that translate into things understandable and measurable by every wingsuiter - sustained horizontal and vertical speeds. As I wrote in their publication on Dec 7 2006,

http://www.pureflyingmagic.com/Content/Knowledge/Resources/Articles/en/WingsuitEquations.pdf

in excitement of discovery,

Quote

Now the unknown aerodynamic parameters (wingloading mg/S and aerodynamic coefficients Cl, Cd) are “hidden” inside coefficients Kl and Kd, which can be easily calculated from sustained horizontal and vertical speeds for a given flight mode, enabling us to solve the equations of motion. See, sometimes you just need to shove the problems under the carpet and all of a sudden it becomes a magic carpet that takes you for an amazing ride. It’s magic... pure flying magic!

(imagine if all problems could be solved just by shoving them under a carpet...)

This trick is what aeronotical engineers don't understand because it's not in their cheat handbooks or university books.

There only two people in the Solar System who get this trick - me and Hartman Rector - and successfully apply it to wingsuit flight, be it theory and software, or analysis and planning of WS BASE flights. Approx. 6,999,999,998, including all aerospice engineers, don't.

Never in the history of aerodynamics, a problem of calculating a trajectory of a glider, standing on a tall cliff and stepping off of it, was needed. Even with NASA's unpowered lifting bodies. Even if they needed to calculate the trajectory of these, they would use the data from windtunnel - coefficients of lift and drag for various angles of attack, planform surface area - to calculate forces at each moment and thus accelerations - and use F=ma at each moment of time to integrate the trajectory. We don't have these - and thanks to WSE we don't need them! - as for us, the sky is the natural windtunnel where the airflow is created not by powerful fans, but by our motion itself; by gravity.

I started wingsuiting in spring 2005 (after about 275 skydives) with Prodigy and then Phantom-1, and in the beginning I didn't even think about science of wingsuit flight (and as most wingsuiters, didn't even understand the difference between L/D and GR). However, I've always been interested in flying the most efficient way, at max glide, and started measuring my flights with GPS (Garmin Vista-C), especially on balloon and heli jumps which I was doing a lot in preparation for WS BASE. And so, I made this embarrassing mistake of treating a straight part of a balloon jump (after wind subtraction, of course) in P-1 as a sustained flight with L/D = 2.9 (while in fact it was GR = 2.9 - it was a slow flare) and in search for the answers, I started really digging the physics of flight, but it took me several months looking at F=ma (expanded with Cl, Cd, S, ro, Vx, Vy, V), until I saw what was hiding from me in plain sight - magic coefficients Kl, Kd. The rest is history. For more than 100 years, WSE were hiding in plain sight.

But it won't ever be on Wikipedia, because of enormous egos of those fighting for dominance on the wingsuit page.

WSE are classic and eternal, the endless blah-blah-blah of aerospice engineers and other uneducated people here will be quickly forgotten, although will be a funny read years later.

Quote

If unpowered flight is considered in a book, it's only dealing with parameters like AoA, Cl, Cd, surface area, etc. - exactly what the trick of WSE manages to avoid completely, since we don't know these parameters

But you know surface area. You can just lay out the suit on the ground and measure it!

You measured AoA with your vane, which is an extremely old device yet you treat it like it's a revolutionary invention.

Quote

Never in the history of aerodynamics, a problem of calculating a trajectory of a glider, standing on a tall cliff and stepping off of it, was needed

NASA never needed to calculate trajectories to land on fixed locations? Glider clubs also have accuracy competitions. You're not only claiming that this problem has never existed before, but additionally you're claiming that wingsuiters do not follow the same laws of aerodynamics as other gliders.

aonsquared

But you know surface area. You can just lay out the suit on the ground and measure it!

You measured AoA with your vane, which is an extremely old device yet you treat it like it's a revolutionary invention.

Surface area by itself is useless if one doesn't know Cl and Cd, because it's the product Cl*S and Cd*S that matters. Same with weight, it's useless by itself. Moreover, the choice of S is arbitrary - doesn't have to be planform area, can be crosssectional area - as long as Cl and Cd are measured with this convention. Again, because only C*S/m matters for dynamics.

Again, poor grasp of aerodynamics and basic math is demonstrated. How can one not see it, when F=ma is expanded in the above PDF, that it's only combination C*S/m that matters for dynamics?

As far as AoA, I never measured it. It's possible with the vane by using a Bluetooth accelerometer mounted on some reference point on body. The problem is... no solid reference point exists on human body! (unless, perhaps, someone has a fully fused colon and has a wireless accelerometer planted in it!)

Here's a speedup footage of a jump that shows this problem.

https://vimeo.com/108428363

The pole with the vane is on quite large and solid (2mm aluminum) belly platform, camera is on the pole close to the vane. The visible oscillations are not vane's; vane is steadily pointing into relative wind from 2-3s from exit till the pull. It is... my breathing! My belly moves as I breath, the pole moves, and although the vane is pointing into the airflow, it appears as if it's wobbling.

So, if 2nd accelerometer was installed on the platform as a body reference, the angle between it and vane will constantly change with every breath, and AoA measurements will be like EKG and essentially useless.

Also, since platform sits a bit differently on different jumps, AoA measured for different jumps will differ even if it actually was the same.

Whatever place we can think on our body to place an accelerometer, it can't serve as consistent reference point because you can't put it on twice exactly, even with 1 degree consistency!

As far as WSE, I'm still patiently waiting for anyone to present equations of motion for a glider, that are actually usable in wingsuiting. Photo or screenshot of a book, or an URL. "Put it up or shut up."

Why could any of this not be proven in the wingsuit wind tunnel once they start changing angle? I’m not sure why there is such an opposition from Yuri for the tunnel.

I think we all agree that GPS doesn’t provide enough information or rather complete/accurate information. Jumping a vane or a pitot doesn’t gather any data that couldn’t be easily obtained in a wingsuit tunnel that is flyable, adjusts in angle, and adjusts air speed.

yuri_base

***Haha I suck at distance use this one instead https://ppc.paralog.net/showtrack.php?track=26136

GPS is garbage and should never be used other than a recorder of coordinates (for example, to show the flight line in WS BASE). All these horizontal (and even vertical, when there are thermals like in BASE) speeds and ground glide ratios are completely useless and misleading in determining the aerodynamic parameters of the wingsuits.
.

I dont know about accuracy, but GPS seems repeatable. I was trying to determine the opening distance of my canopy using both a FlySight and conventional digital altimeter. The altimeter varied by more than 200-300' each jump, but the GPS almost always said the same thing. Sometimes it showed a longer or shorter deployment, but in those cases I could physically feel the canopy taking longer or shorter to open.

I seem to recall the GPS tells you what its accuracy is for each measurement and for most measurements it was telling me it was accurate to less than 1 MPH and less than a few feet of elevation.

Westerly

***GPS is garbage and should never be used other than a recorder of coordinates (for example, to show the flight line in WS BASE). All these horizontal (and even vertical, when there are thermals like in BASE) speeds and ground glide ratios are completely useless and misleading in determining the aerodynamic parameters of the wingsuits.

I dont know about accuracy, but GPS seems repeatable. I was trying to determine the opening distance of my canopy using both a FlySight and conventional digital altimeter. The altimeter varied by more than 200-300' each jump, but the GPS almost always said the same thing. Sometimes it showed a longer or shorter deployment, but in those cases I could physically feel the canopy taking longer or shorter to open.

I seem to recall the GPS tells you what its accuracy is for each measurement and for most measurements it was telling me it was accurate to less than 1 MPH and less than a few feet of elevation.

I'm not talking about GPS accuracy, it's GE (good enough). I personally own several excellent GPSs: Dual XGPS160 (10Hz), XGPS-150 (5Hz), Bad Elf GPS Pro (10Hz), Emprum UltiMate GPS (5Hz, 30-pin plug for iPhone 4), owned but lost WBT-201 (5Hz). (Never owned Flysight, since for its price I can buy two fast GPSs that can send data to the phone via Bluetooth, as well as record it in internal storage. So they can be used with many apps, compatible with these devices.) Besides high enough sample frequency, they are also very accurate. (The first 3 are also compatible with L/D Magic; Emprum was compatible until Apple froze ios version on the 4 and the app had to move up.)

I'm talking about WIND. Wind can never be subtracted from GPS data. Not with precision we need (1mph minimum). Nobody knows exact winds at altitude, exact wind profile. I found the aviation wind data to be very inaccurate; can't be relied upon for our purposes, it's just a ballpark for aviators. The closest to measuring the exact wind profile is to record the track of balloon's ascent on a balloon jump. Even then, wind profile is very time and place dependent - balloon moved several miles for 20 minutes, it's quite different winds there! (And I know this from experience, as I did a looooot of balloon jumps back in 2005-2011.)

Even in BASE, it's quite often that there's no wind on exit, no wind in LZ, yet there's full-stop (20mph) wind at opening altitude and, no doubt, somewhere between exit and opening - this will affect wingsuit GPS data as well. Even if it's a crosswind - still, 1mph precision we need is easily destroyed by crosswind. Also, thermals are a huge problem in BASE for GPS data: last year, I had a truly bizzare experience (and not me alone, a bunch of other jumpers as well) - jump, and after only 2-3 seconds, you're flying purely horizontally for about 10-15 seconds , because of insanely powerful thermal column cancelling your vertical speed. Too bad I didn't have a GPS with me - could show to naive folks, look, I flew at infinite "L/D"!

As I demonstrated above, the same pilot in the same suit - very, very experienced, very consistent and very good at flying and competitions, multiple champion - flew 80mph slower (!) in one place than the other. That's the difference between headwind and tailwind. Unaccountable, because the wind/profile is unknown.

GPS data is useless, unless it's just to measure the total distance in competition (since that, not L/D, is what they agreed to compete on).

I've long gave up on using GPS in wingsuiting. The only reason, for example, Smart Altimeter and L/D Vario support GPS, if the smartdevice doesn't have a barometer, is to please the Google/Apple/Microsoft app reviewers and get the app approved in the stores, because when their testers were opening the app on their test device, it was showing nothing, although the app clearly stated that barometer is required. After rejection and dragging this for weeks, I gave in and included GPS for altitude measurements. Just to please them dumb testers. GPS is slow, loses signal and overall just PITA. Barometer works always, and is very fast and accurate.

Fuck GPS!!!

By the way,

aonsquared

vane, which is an extremely old device yet you treat it like it's a revolutionary invention.

is 100% true. From https://en.wikipedia.org/wiki/Weather_vane,

Quote

The weather vane was independently invented in ancient China and Greece around the same time during the 2nd century BCE.

I didn't invent the vane. I invented the accelerometer on a vane as L/D meter principle.

[inline GlideAngleMeter.jpg]

Besides sustained flight, I proved that it measures L/D also at any time of non-sustained, 2D flight as well. About 3 years ago, I also proved that the principle is valid for 3D gliding flight as well (not published, but mentioned here on bj.com, still in one of my Moleskins), as long as the turns are coordinated (no side slip); even if turns are a bit sloppy (not as if on rails), the difference in measured L/D from the actual L/D is quite small.

Besides accelerometer, a simple bubble can be used as an analog L/D meter:

[inline BubbleLD.jpg]

(The marks are from 1.5 to 2.5 in 0.1 increments; black one is 2.0; the curve is special mathematically derived curve precision laser-cut in acrylic. My max L/D in Phantom-1 measured with this device was 2.15, consistent with data obtained with other means, such as L/D Calculator in Wingsuit Studio from BASE jumps.)

They didn't invent this principle in China and Greece in the 2nd century BC. It was invented in the USA more than 2000 years later, in 2006.

But it has been totally ignored by the stooges (WSMs and most WS pilots except precisely one) for 12 years, and counting!

To further show that PPC data (other than overall measurements - distance, time, avg. speed - necessary to determine winners) is useless for wingsuit R&D, imagine this hypothetic scenario:

They reduce the altitude window from 1000m to 1000ft. (more than 3x)


BAM!!! Now one can ask around best pilots about what is top L/D and they will say something like, "15:1... not quite yet 20:1". Because in smaller window, you can maintain much higher average GR than in large window.

Isn't this complete ridiculousness? The wingsuits haven't changed overnight, but their L/D increased many times overnight! Wow! Huge progress in wingsuiting!

Here's something else interesting regarding PPC. Check out the results at a place called "Rochelle". Sort by timestamp, descending.

https://ppc.paralog.net/listtracks.php?place=Rochelle

[inline Rochelle.png]

On 2016-10-23, two guys went to Rochelle (only 2!) and set "world records" in distance and speed. Wow! They must have flown some secret new wingsuit prototypes!

Or is it some kind of "distance/speed PPC tourism" where they look for forecasts of strongest upper winds (with acceptable landable ground winds) and go to this place and set these fake "world records"?

“I am very smart👌🏻, so much smarter that’s you🖐🏻, probably the smartest 👌🏻 person ever☝🏻.” - yuri


Why don’t you publish? You have a PhD. You know how the process works. I’m sure there is some masters or PhD student that you could work with to get published.

LeeroyJenkins

“I am very smart👌🏻, so much smarter that’s you🖐🏻, probably the smartest 👌🏻 person ever☝🏻.” - yuri


Why don’t you publish? You have a PhD. You know how the process works. I’m sure there is some masters or PhD student that you could work with to get published.

I've already asked him that. His stuff has probably been rejected by Wikipedia (they have strict rules against self-promotion) so it's unlikely any paper he writes will be accepted.

yuri_base

WSE are classic and eternal

They'll last as long as the people who think they're correct, and the server hosting on his website. And given his luck trying to convince people in the past 12 years (but refusing to provide proof), I wouldn't bet on it...