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yuri_base

Wingsuit research

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aonsquared


You don't need yuri's equations for that. Any glider pilot knows that on a constant airspeed and constant glide, your L/D ratio is roughly constant. What's new?

Also, how was the green line calculated?



It wasn't constant airspeed nor constant glide. The flight went through a few phases and angles of attack, but as much as possible, the same body configuration.

The green line is groundspeed / fallrate, the purple line is L/D calculated based on wingsuit equations.

Although, I guess technically it doesn't actually require yuri's "magic" kl or kd coefficients to calculate L/D. Just change coordinate system to be oriented along the velocity vector, subtract out gravity, and what remains are lift and drag forces.

However the magic coefficients do lead to interesting results when it comes to modelling the effects of mass, surface area, altitude, etc. I'm still trying to wrap my head around sustained speeds.
BASEline - Wingsuit Flight Computer

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platypii

It wasn't constant airspeed nor constant glide. The flight went through a few phases and angles of attack, but as much as possible, the same body configuration.



Then your hypothesis is already incorrect. Why should L/D ratio remain constant if you change angle of attack?

Roughly constant body configuration should result in roughly constant profile drag though. Is that what you're calculating?

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platypii

It wasn't constant airspeed nor constant glide. The flight went through a few phases and angles of attack, but as much as possible, the same body configuration.

The green line is groundspeed / fallrate, the purple line is L/D calculated based on wingsuit equations.



Also, that doesn't match what you show on the graph. Red line shows a steady, linear decrease in altitude vs. time, which implies constant vertical speed.

Is the green line from the GPS? Could you also include PDOP (position dilution of precision) in the graph so we can see how accurate it was? With high (bad) PDOP values a GPS can show hundreds of m/s speed while the receiver is not moving.

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aonsquared


Then your hypothesis is already incorrect. Why should L/D ratio remain constant if you change angle of attack?

Roughly constant body configuration should result in roughly constant profile drag though. Is that what you're calculating?



Fair enough, you're right that with changes in airspeed and angle of attack, the L/D will also change. I glossed over this a little, but also tried to acknowledge it when I pointed out the variation in L/D in a typical glider polar curve.

The L/D will change throughout a flight, but not by very much actually. It will change by moving along the wingsuit's characteristic polar curve. The l/d won't swing between wildly between 2:1 and 5:1 like the glide ratio does.

Here is a chart of the "sustained speed polar" which uses the wingsuit equations to compute "sustained" horizontal and vertical speeds. In theory this is roughly what would be measured by aerodynamic instruments like airspeed and glide angle on an aircraft. The purple line shows the sustained speeds from the same jump as above, and you can see they fall within a fairly narrow range. The green line is my attempt at ballpark estimating a wingsuit's polar curve. That's why I would expect the L/D to not vary by much throughout the flight.

[inline polar.png]

Big caveat: the wingsuit equations can re-orient and change the frame of reference of the measurements, but wind still throws off the results.
BASEline - Wingsuit Flight Computer

polar.png

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aonsquared


Also, that doesn't match what you show on the graph. Red line shows a steady, linear decrease in altitude vs. time, which implies constant vertical speed.

Is the green line from the GPS? Could you also include PDOP (position dilution of precision) in the graph so we can see how accurate it was? With high (bad) PDOP values a GPS can show hundreds of m/s speed while the receiver is not moving.



Chart attached with all speeds: total, groundspeed, fallrate. Plus glide and l/d.

Accuracy on this track seems okay. Jump is sensitive, so can't share the data, but will see if I can find a similar one that I can.
BASEline - Wingsuit Flight Computer

allspeeds.png

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platypii

The l/d won't swing between wildly between 2:1 and 5:1 like the glide ratio does.



It's a bit unfair to say that glide ratio varies massively without posting details of what instrument you used to measure glide ratio. If it's GPS, please post how the PDOP varied throughout the flight.

Same for the red line please - what instrument was used to measure it? The linear steady decrease indicates a roughly constant vertical (and thus horizontal) speed.

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Thanks for the plot. Now it's a bit clearer.

First off - instantaneous glide ratio is not a measure of L/D ratio and should not be. In the flat part of a flare (vertical speed = 0 for a fraction of a second) then instantaneous glide ratio would be infinity.

However average glide ratio over the entire flight can give an indication of total L/D ratio. So if you integrate the area under the glide ratio curve then average over the interval, you should get to a similar value. You still need PDOP values though, as no instrument is perfectly accurate even with filtering. And you need to post filtering details too...science is difficult, but it does pay off when done properly and without taking shortcuts :)
Again, I'm not really seeing anything new or revolutionary?

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Aons,

Did you also notice that the graph posted is a very slow and floaty flight?

Platypii,

Quote

Maybe you missed the part where I followed up with real world experience? And also explained how one can test if experience lines up with theory



I saw that. I have also played around with his equations. My biggest problem with Yuri's idea is the fact that he thinks it will revolutionize wingsuit design. It wont, the limiting factor of wingsuit design is the air frame, AKA the human body.

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For someone claiming to be expert on research you’re quite far behind on developments...we’re not wanking on someone flying 60 seconds of Kjerag anymore...most people live in 2018:)
My record is the worlds first correct, scientificly verified record as stated..
visit sweden if you want to learn something (about doing more than flying in a straight line and planking;)) inluding actual fixed L/D results.

Quote

he number of people in the Solar System (and possibly, in the Universe) who understand Wingsuit Equations and their value, has just quantum-leaped to THREE.



Meanwhile, same people still got nothing in knowledge beyond straight line flying. Stop living in 1999...there are people with the intelect of a goat doing more eith their wingsuit in both performance and/or agility. I know a lot of violin theory, but still cant play one...:P
JC
FlyLikeBrick
I'm an Athlete?

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platypii

Chart attached with all speeds: total, groundspeed, fallrate. Plus glide and l/d.



This chart is a perfect demo of the trick I mentioned above. Look for intersections of GR and L/D curves: at these points, Vx has an extremum (i.e. horizontal acceleration is 0, but vertical doesn't need to be - it doesn't need to be a sustained point!) This trick is useful "in the field" when someone shows the data from their flights (straight, no wind) - look for extrema in Vx, and in these points, L/D will be equal to [air] GR.

This immediately follows from the 1st WSE equation:

ax = g*V*(Kl*Vy - Kd*Vx)

if ax = 0 then Kl*Vy = Kd*Vx, or Kl/Kd = Vx/Vy, or L/D = GR.

Several other useful tricks exist as well. WSE are like a Pandora box, one can pull so much useful stuff out of them!
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

***Chart attached with all speeds: total, groundspeed, fallrate. Plus glide and l/d.



This chart is a perfect demo of the trick I mentioned above. Look for intersections of GR and L/D curves: at these points, Vx has an extremum (i.e. horizontal acceleration is 0, but vertical doesn't need to be - it doesn't need to be a sustained point!) This trick is useful "in the field" when someone shows the data from their flights (straight, no wind) - look for extrema in Vx, and in these points, L/D will be equal to [air] GR.

This immediately follows from the 1st WSE equation:

ax = g*V*(Kl*Vy - Kd*Vx)

if ax = 0 then Kl*Vy = Kd*Vx, or Kl/Kd = Vx/Vy, or L/D = GR.

Several other useful tricks exist as well. WSE are like a Pandora box, one can pull so much useful stuff out of them!


You don’t need wse for that, it’s basic glider aerodynamics.

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Here's a good read from the past RE: "next advancements in wingsuits".

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=2030077;page=1;mh=-1;;sb=post_latest_reply;so=ASC

I like these quotes from it:

Quote

Read your aerodynamics boys and girls, all the answers is right there. Think for your selfs, dont let a few guys at the leading companies be the ones to "rule the world" with their, no offense, limited insight in human flight. We have proved them wrong in tracking suits and techniqes, and will do the same with the overprized and oversized wingsuits ;)



Quote

Some with vested interests do appear to want us to believe that the suits won't get much better than they aleady are. They're still trying to sell us their out of date suits.
This attitude is not uncommon in skydiving and if these guys are recommending out of date and inadequate gear just because they're selling it then it's BS sucksville.

Any-one with even a slight knowledge of aircraft history would know such dead-end thinking is totally bogus. The Wright flyer may have been first but it was a failure in most other respects.

Of course some will be more interested in flocking than maxing out.....but the edge will be with those seeking maximum performance.



Quote

Imitating flying squirrels is a 20th century thing, after all.



Quote

Where there is passion there will always be innovation.



Quote

wow, shit like this is probably why there ARE BASE ONLY individuals. a few people are redefining "wingsuiting" right now and they are doing by themselves for their own reasons. needless to say, which will probably benifit everyone in due time.


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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platypii

Fair enough, you're right that with changes in airspeed and angle of attack, the L/D will also change. I glossed over this a little, but also tried to acknowledge it when I pointed out the variation in L/D in a typical glider polar curve.

The L/D will change throughout a flight, but not by very much actually. It will change by moving along the wingsuit's characteristic polar curve. The l/d won't swing between wildly between 2:1 and 5:1 like the glide ratio does.

Here is a chart of the "sustained speed polar" which uses the wingsuit equations to compute "sustained" horizontal and vertical speeds. In theory this is roughly what would be measured by aerodynamic instruments like airspeed and glide angle on an aircraft. The purple line shows the sustained speeds from the same jump as above, and you can see they fall within a fairly narrow range. The green line is my attempt at ballpark estimating a wingsuit's polar curve. That's why I would expect the L/D to not vary by much throughout the flight.



platypii

Chart attached with all speeds: total, groundspeed, fallrate. Plus glide and l/d.

Accuracy on this track seems okay. Jump is sensitive, so can't share the data, but will see if I can find a similar one that I can.



Platypii,

I think you need to step back here and look at your logical reasoning. You made a hypothesis (L/D ratio is roughly constant on this flight), then measured ground Vx and Vy through GPS.

Then critically, without measuring lift nor drag nor its ratio with any other method, you say that since the L/D calculated from yuri's equations looks like your hypothesis, then it must be correct.

You looked at glide ratio varying wildly and stayed on this train of thought: "it doesn't match my hypothesis, so it must be wrong". (and yes, instantaneous GR is definitely not a sensible aerodynamic measure, but instantaneous GR being wrong doesn't automatically mean yuri's equations are correct)

But why not use any number that stays roughly constant?

I can multiply air density by 2.44 and tell you it's L/D ratio for your flight, and it would match your hypothesis better than the GR data, but there would be no logic behind it.

To properly prove something, it needs to be able to make predictions that are independently verifiable, and not just because it "looks" right.

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aonsquared

***Fair enough, you're right that with changes in airspeed and angle of attack, the L/D will also change. I glossed over this a little, but also tried to acknowledge it when I pointed out the variation in L/D in a typical glider polar curve.

The L/D will change throughout a flight, but not by very much actually. It will change by moving along the wingsuit's characteristic polar curve. The l/d won't swing between wildly between 2:1 and 5:1 like the glide ratio does.

Here is a chart of the "sustained speed polar" which uses the wingsuit equations to compute "sustained" horizontal and vertical speeds. In theory this is roughly what would be measured by aerodynamic instruments like airspeed and glide angle on an aircraft. The purple line shows the sustained speeds from the same jump as above, and you can see they fall within a fairly narrow range. The green line is my attempt at ballpark estimating a wingsuit's polar curve. That's why I would expect the L/D to not vary by much throughout the flight.



platypii

Chart attached with all speeds: total, groundspeed, fallrate. Plus glide and l/d.

Accuracy on this track seems okay. Jump is sensitive, so can't share the data, but will see if I can find a similar one that I can.



Platypii,

I think you need to step back here and look at your logical reasoning. You made a hypothesis (L/D ratio is roughly constant on this flight), then measured ground Vx and Vy through GPS.

Then critically, without measuring lift nor drag nor its ratio with any other method, you say that since the L/D calculated from yuri's equations looks like your hypothesis, then it must be correct.

You looked at glide ratio varying wildly and stayed on this train of thought: "it doesn't match my hypothesis, so it must be wrong". (and yes, instantaneous GR is definitely not a sensible aerodynamic measure, but instantaneous GR being wrong doesn't automatically mean yuri's equations are correct)

But why not use any number that stays roughly constant?

I can multiply air density by 2.44 and tell you it's L/D ratio for your flight, and it would match your hypothesis better than the GR data, but there would be no logic behind it.

To properly prove something, it needs to be able to make predictions that are independently verifiable, and not just because it "looks" right.

Im pretty sure this is how he came up with his equations. They prove what he wants them to and nothing more.

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Here's the algorithm for calculating L/D and sustained polar speeds (aka "flight mode"), as well as absolute values for lift and drag, and even dimensionless coefficients of lift and drag - from GPS data of a jump in *no wind* (which sometimes happens in WS BASE - but not always, even if there's no wind at exit and LZ!).

Start with Wingsuit Equations, [1]

ax = g*V*(Kl*Vy - Kd*Vx)
ay = g - g*V*(Kl*Vx + Kd*Vy)


If Vx, Vy are known from GPS, then V=sqrt(Vx^2+Vy^2), ax=dVx/dt, ay=dVy/dt can be calculated. Then, we have 2 linear equations with 2 unknowns, Kl and Kd. The solution of it is, [2]

Kl = ((g - ay)*Vx + ax*Vy)/(g*V^3)
Kd = ((g - ay)*Vy - ax*Vx)/(g*V^3)


Their ratio is equal to lift-to-drag ratio: [3]

L/D = Kl/Kd = ((g - ay)*Vx + ax*Vy)/((g - ay)*Vy - ax*Vx)

Sustained horizontal and vertical airspeeds: [4]

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


These sustained speeds can be normalized to sea level by multiplying them by square root of ratio of air density at current altitude AMSL h to standard air density at sea level: [5]

Vxs(0) = Vxs(h)*sqrt(ro(h)/ro(0))
Vys(0) = Vys(h)*sqrt(ro(h)/ro(0))


The pair of such normalized sustained speeds [Vxs0, Vys0] is called a flight mode and is a point on this pilot's/wingsuit's polar curve.

Lift and drag can be calculated, if the total weight is known, W: [6]

L = W*Kl*V^2
D = W*Kd*V^2


Alternatively, weight is not necessary if we determine lift and drag as percentages of weight: [7]

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


Dimensionless lift and drag coefficients can be determined if we know weight W and planform area S: [8]

Cl = 2*W*Kl/(ro*S)
Cd = 2*W*Kd/(ro*S)


(even if we don't know planform area, Cl and Cd can be calculated in "per square meter" sense, by using S = 1m^2).

Since calculating accelerations from speed data amplifies noise, the results calculated straight with these formulas can be quite noisy. To reduce the noise, advanced filtering using Kalman filter with WSE serving as its physical model, can be used. An example of using Extended Kalman filter for a vane with an accelerometer, is here:

http://www.pureflyingmagic.com/Content/Knowledge/Resources/Articles/en/HowLDMagicWorks.pdf
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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Also, for a smartdevice (each smartphone/smartwatch these days has an accelerometer) on a vane, the components of apparent gravity perpendicular to the vane, and parallel to the vane (i.e. direction of the relative wind), are related to magic coefficients as: [9]

g_|_ = g*Kl*V^2
g|| = g*Kd*V^2


And, of course, it follows from this, the classic - the accelerometer-on-vane principle: [10]

L/D = g_|_/g||

(this is used by L/D Vario to measure L/D in real time)
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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It's funny (and sad at the same time) to even think that if all this theory, apps, and instrumentation was offered not by "some dude Yuri", but by one of the WSMs, everybody would sing alleluias and scream in orgasm, "wow, this is amazing! ingenious! so revolutionary! our King is so great! shut up and take my money!", sheep stuff like that.

Probably, the situation is a great illustration to the famous Dostoevsky's quote:


Fyodor Dostoevsky

"There are three Powers, three unique Forces upon earth, capable of conquering for ever by charming the conscience of these weak rebels--men--for their own good; and these Forces are: Miracle, Mystery and Authority."



The Grand Inquisitor


These weak men can only kneel to Authority they worship. They can't accept the Truth presented by one of their peers. They can't handle the Truth.

Such shame!


PS. Haha, found even a better quote from the genius:

Fyodor Dostoevsky

"There exists no greater or more painful anxiety for a man who has freed himself from all religious bias, than how he shall soonest find a new object or idea to worship. But man seeks to bow before that only which is recognized by the greater majority, if not by all his fellow-men, as having a right to be worshipped; whose rights are so unquestionable that men agree unanimously to bow down to it. For the chief concern of these miserable creatures is not to find and worship the idol of their own choice, but to discover that which all others will believe in, and consent to bow down to in a mass."


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

It's funny (and sad at the same time) to even think that if all this theory, apps, and instrumentation was offered not by "some dude Yuri", but by one of the WSMs, everybody would sing alleluias and scream in orgasm, "wow, this is amazing! ingenious! so revolutionary! our King is so great! shut up and take my money!", sheep stuff like that.

Probably, the situation is a great illustration to the famous Dostoevsky's quote:


***"There are three Powers, three unique Forces upon earth, capable of conquering for ever by charming the conscience of these weak rebels--men--for their own good; and these Forces are: Miracle, Mystery and Authority."



The Grand Inquisitor


These weak men can only kneel to Authority they worship. They can't accept the Truth presented by one of their peers. They can't handle the Truth.

Such shame!


PS. Haha, found even a better quote from the genius:

Fyodor Dostoevsky

"There exists no greater or more painful anxiety for a man who has freed himself from all religious bias, than how he shall soonest find a new object or idea to worship. But man seeks to bow before that only which is recognized by the greater majority, if not by all his fellow-men, as having a right to be worshipped; whose rights are so unquestionable that men agree unanimously to bow down to it. For the chief concern of these miserable creatures is not to find and worship the idol of their own choice, but to discover that which all others will believe in, and consent to bow down to in a mass."



Whats your wing loading when you include the weight of your ego?


But really, if wingsuit manufactures posted the same nonsense you did, people like aonsquared and I would still criticize them. One thing I do know however, the aerospace engineers that work to design these suits understand aerodynamics way more than you do. You can't even answer simple questions because you know the answer will undo your theories.

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mccordia

there are people with the intelect of a goat doing more eith their wingsuit in both performance and/or agility.



Like this guy with the last name starting with "C" who almost killed another jumper (who's still recovering and has a long recovery road ahead and a lot of $$$ to pay for somebody's agile mistake)?

Quote

C gave the break-off signal, switched on his back and made a 90 degree turn towards the DZ, violating break-off procedures. Several seconds later, he collided with K, who was in his designated break-off sector. As a result of the collision, K lost consciousness and remained in freefall until AAD fire.



http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4886029

Happen to know this agile pilot "C"? Perhaps, brush his teeth every morning? :ph34r:
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 wouldn't even reply to Jarno's useless noise post, but today I learnt (an update was posted in Russian forum about May 24th accident in Kolomna, I missed that thread first time around) about this and that Vasily's (and his mother's) lives are essentially ruined by this guy who even has this hutzpah to post here his nonsense with insults accompanied by a bunch of smilies.

jcbfly

Any updates on this incident? Seems like the basic rule of "you gotta plan the dive and then dive the plan" was ignored in this case.



Quote

From the Russian forum,

http://www.skycentre.net/topic/23850-270518-клмн-столкновение-во-время-винг-разбежки-тяжелые-травмы/?page=1

(requires registration)

September 12, update from his mother:

"Behind are the 3 weeks in resuscitation unit and 1.5 months in neurosurgery clinic/institute. Now recovering in the hospital of Russian Emergency Ministry. Vasily makes progress: sits in wheelchair, learns to walk and to do day-to-day actions (eat, dress, etc.), takes sessions with speech specialist and neuropsychologist. But there are serious deviations in health caused by severe brain trauma, and Vasily hasn't became yet "himself", he can't live without external help and needs the continuing care and recovery. Taking into account this slow recovery progress, it would take, in the best scenario, at least a half year of care and rehabilitation.

Clinics with decent care charge about $5000/mo. This is the reality. We would appreciate any financial help."

They need to hire a caretaker so that his mother can go back to work to pay for the huge bills.


So, once again, why the name of the person who ruined somebody's life (and mother's) - Jarno Cordia - is kept secret? (it's not secret on the Russian forum)


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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