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Topgunbase interviews Eric Dossantos, following his survival after a full-flight tree impact in Chamonix last month.

http://topgunbase.ws/...ke-up-in-a-hospital/

Wow.

That's a great interview too.

Great read, made my back hurt for some reason.

Hope the video will also be shared at some point (with a suitable fade out).

Not trying to be a dick or anything, I will also fully disclose that my WS-experience is limited to about 50 jumps from planes.

Is it just me or does it look like you were already slow after you crossed the ridge, and it only got worse once you entered the last part through the trees. There was a point the windnoise would almost go to zero. I expected to see you drop from the sky WAY before actual impact.

Is that not the video at the top of the article?

my bad, video didn't load for me at first

I thought the same.

One of the main problems here is he went from two jumps on a Havoc to flying a Vampire Race. I mean, come on! The Sukhoi has been on the market for quite some time now!

All jokes aside:

This is some of the best stuff I've read in a while. Thank you Eric and Richard. It takes a real man to own his mistakes, put the ego aside and share them with the rest of us. Sincerely, thank you.

You can watch the video without issue here http://topgunbase.ws/wp-content/uploads/2016/10/540-Med-Eric.mp4?_=1

That tree totally gave it's life for him. He better go plant about 1000 more in appreciation! I hope he saved a piece as a reminder. Maybe he could whittle it into an urn or something.

I know a man that has a piece of a tree on his wall. He pulled though. Both handles.

No, it's not just you - in fact it's kinda the whole point of the in-depth interview that accompanies the video. Which you should definitely, definitely read!

I disagree. It may well change things for some of the people that read it, because it should read like an extremely uncomfortable view into what's going on inside their/our own heads.

What the video shows (and what is painfully obvious to any semi-competent WSer that watches it) is a super slow flight from start to finish that ends in disaster because there is no energy left.

What the interview explains is how someone can be flying like that, surrounded by more competent pilots flying much faster, and still fool themselves into thinking they're doing fine

Most of us hopefully know what we should be doing - it's often the times we convince ourselves that it's OK not to do it that are the problem; and this interview is a pretty brutal expose of that mindset.

I think you nailed it with this post.

"There are so many things to take away from this. If you see something dangerous, man up, grow a thick skin, and say what’s on your mind, right then and there."

Good read and vid.

Another lesson: learn to pick up on subtle cues about your own behavior.

BASE jumpers, as a general rule, are reluctant to tell a jumper that they shouldn't be doing something. The reasons for this are inherent in the sport: most people in the world consider what we do to be stupid. So who are we to tell someone else where to draw the line when it comes to risk/reward?

So, if you ever hear a jumper tell you something like "hey are you sure you're ready for this?" or an offhand comment about flying a little slow. TAKE THAT SERIOUSLY, because that's generally about as strong of a statement as you'll ever get from a fellow jumper.

Unless Douggs is around

Well I have seen Douggs going for deep and low, and only a 180 will save his ass, and guess what, he got a clean 180.

We have all been there trying to find out by our selves, learning by doing. At least some of us,

I'm not seeing the super slow flight..
compare some waypoint markers to this clip
https://www.youtube.com/watch?v=kt4o87aItJA
I think this accident had more to do with Eric's flight path than his speed ( he could have made the tunnel road switchback lz easily )

Douggs will definitely tell you how it is, good or bad. Man I love that cunt

+1, and great example!

After watching Eric's video over 9000 times and reading the interview over the couple of days, I came to a very different conclusion than a quick initial dismissive one, "Eh, just another idiot who wanted to be a youtube star, too soon, too quick". I think Eric can ease up beating himself so hard and deserves a bit of a rehabilitation.

(Note: the youtube video in the article is sped up and is not particularly useful for us; watch the raw version: http://topgunbase.ws/.../10/540-Med-Eric.mp4)

The more I watched the video and read Eric's description, the more it all made sense together. So, let's go slowly, step by step.

He starts good, at 0:22 timecode. No problem here. At 0:41 in video (19s in flight) he passes final pillars on the right and soon after flies into open air, and he has a healthy amount of forward speed. Nothing seems unusual here.

Then,

"My idea was to fly a right line towards the refuge to test how different inputs would improve my approach for a fly by. I’d aim toward the mid-station, and see how high I was flying."

- we see (and hear) him slowing down considerably. He's looking forward, at the Impact Point (IP) - the starfield effect epicenter. He's evaluating if he can fly over the refuge (and possibly into Le Blaitiere line?) Aiming a bit to the right of the refuge - toward the cable car mid-station. He is testing if this flight mode will get him there high enough to proceed. So far, all goes as intended.

Looks like he wants to fly at sustained max L/D to get to the mid-station as high as possible, but trades too much of horizontal speed into better glide ratio - which is only temporary, as basic wingsuit physics tells us that to have GR > L/D, you have to be decelerating. Essentially, he does a slow, almost unnoticeable flare after passing the pillars, and rides high GR of this flare. Like slowly giving rear riser or brake input under canopy - except with wingsuit, this slow flare can last much longer than under canopy, due to higher wingloading. But not forever.

He spends quite some time in this flight mode (possibly tweaking configuration to see the effect), until about 1:25 (63s flight time) where it's obvious the IP is way below the mid-station - he cannot make it. No problem - he used the "skydive" portion of the jump to do some safe experiments, which should be applauded.

"If I didn’t like how high I was, I would just turn left to fly Cheese Grater line instead. As it turned out, I noticed early that I’d be too low to fly over the refuge, so I flew Cheese Grater"

So far, it goes by the decision tree he planned ahead. He turns into Cheese Crater (sp?) line and picks up speed as he is diving under the wires. The speed at entrance seems to be healthy enough, it doesn't immediately scream "too slow, abort!" Now we know that it doesn't have a healthy margin above that minimum passable speed, but it looks passable:

"At that moment, I actually felt fine to turn onto the Cheese Grater line. Based on my previous jumps on that line, I honestly thought I would have no problems."

Let's compare waypoints as Rotbrett suggested. Here's pretty much the same point, except Eric is a bit more to the left - 1:45 in Eric's video and 0:02 in the other.



Exactly 10s later they're at exact same spot above the switchback of the trail:



Judging by the shadow, Eric is fully stretched, flat as a plank, arms in some dihedral for more speed. Doesn't look head-high. It all doesn't look troublesome so far. Everything is almost exactly the same as in the other video.

4 more seconds later, same spot:



And only then he slows down slightly, here's the same spot where he's at 19s, vs 18s for other guys:



The 1-second lag continues to the point where he starts flying out of the ditch while the orange guys continue farther into it. Now, with lower speed, he flattens his glide, which results in... (physics!) more lost speed.

"- As you’re watching your POV video of this flight [5 sec prior to impact], do you feel you have the speed to aggressively flare and get out of this line?

- No, not at all. I was actually expecting to continue flying straight and have the trees drop out from underneath me.

- Was this a normal flight condition for you on this line?

- Honestly, yeah… Cheese Grater is sort of a flat-ish line. But I had always disconnected at a certain point about halfway down, and I always made my normal LZ."

So if we only think about why he got into trouble and the other guys did not, we conclude that he lost some speed at the bottom portion of his line most likely due to maneuvering between the trees and doing little (very little!) flares when he felt a bit too close to the ground, and finally did a bit too much flare (but still, a small flare) while disconnecting, while the other guys continued down and kept their speed.

So, in relative terms, he made only a very small mistake, compared to the other video, but it lead to a dramatically different outcome.

The logical conclusion is that in both cases, speed was not sufficient enough to provide sufficient margin, in both cases, margin for error was nearly zero. It's just Eric dipped a bit below it. His 10 or so jumps before this one were just like the other guys'. So he thought good about it.

"- Looks like you had an ‘out’ to the left about 10 seconds prior to impact, and you didn’t take it. Why?

- I hadn’t planned for an ‘out’. I honestly didn’t expect to need one. I was just thinking about flying straight to my normal LZ. In hindsight, I think I was stuck on my ‘gameplan’ and obviously didn’t have the awareness to adjust inflight, especially when staying in the line longer than normal."

"It wasn’t until about the last 5 seconds that I felt the trees below me getting closer than I expected or wanted. Everything before that felt flyable to me."

Sans the small mistake near the end of flight, it looks like Eric's flying was exactly like a lot of other jumpers fly it.

(When watching various proximity videos which look faster than this, take into account the cinematic distortion of some lenses or in post processing which makes footage look faster than it actually is; also, time of day/light conditions: the lower the light, the longer the exposure of each frame, which smears it more and makes impression of greater speed.)

Now, let's talk about experience.

"Currently, I’ve been skydiving for 4 years (900 total / 550 wingsuit), and basejumping for 2 years. I only have about 80 slider-off jumps, about 40 tracking jumps, and 105 WS base jumps."

Not shabby at all. I'd say, appropriate for some cautious proximity. Flying high enough above Cheese Crater? - Why not. Flying this close? Not a good idea. But overall, this amount of experience does not raise a red flag. His starts are solid. Just continue "skydiving" off the Midi, with very cautious brief proximity here and there, and he'd be fine.

So, these arguments, in my mind, changed my opinion from dismissive to... "hmm, can we actually learn something deeper here rather than just kicking the 'dead man walking'"? Because it looks like there are many, many jumpers flying like this, not understanding THAT and WHY they have virtually zero margin of error.

What many do not realize is that total speed alone is not an indicator of a healthy flight. To saying "fly fast" we must always - ALWAYS! - add "...horizontally". Never just say "fly fast". Always say "fly fast HORIZONTALLY". This is because wingsuit dynamics works in such a way that to a given total airspeed there can correspond many very different flight modes. Including modes that have no ability to detach from the line at will.

Imagine a thought experiment. Same pilot does proximity over some very smooth grassy slopes with no features that would indicate how steep the slope is. In one case, he's flying 120mph forward, 80mph down (1.5:1 slope), his total speed along the slope is 144mph (120*120 + 80*80 = 144*144). In the other, he's flying 102mph forward, 102mph down (1:1 slope), his total speed along the slope is 144mph (102*102 + 102*102 = 144*144). Pythagorus, the best wingsuiter's friend.

In both cases, his total speed is the same. The buzzing grass below will be zooming past equally fast. And because it's impossible to tell exactly what slope is, the flights will feel about the same (in first-person POV video - virtually indistinguishable). Even body configuration can be the same: say, arms in some dihedral, body line pitched 5 degrees below horizon. But the flight modes are different: L/D = 1.5, AoA = atan(1/1.5) - 5 = 34 - 5 = 29 degrees in the former; L/D = 1.0, AoA = atan(1/1) - 5 = 45 - 5 = 40 degrees in the latter. The latter mode, at 40 degrees angle of attack, is actually an aerodynamic stall, while the former, at 29, while is still aerodynamically "dirty", but not quite a stall-stall, at least in wingsuiting sense.

Here's a little illustration: Wingsuit Polar Region - an area on horizontal-vs-vertical sustained (important!) speed graph where a wingsuit pilot can be, and cannot be outside of it no matter what (in sustained flight, i.e. strictly constant both horizontal and vertical speed, indefinitely; of course, dynamic maneuvers allow achieving speeds outside of WPR, but only briefly.)



Circle lines represent constant total speed, and we can see from their intersections with WPR that there can be many, many very different flight configurations with the same total airspeed.

Ability to climb out depends not only on total speed, but in greater extent on L/D, so that L/D = 1.5 will have greater ability to convert speed to detachment from the line than 1.0. Poor L/D = poor ability to utilize speed for life-saving or fun purposes; high L/D opens many possibilities. Rising L/D from low 2-ish of early wingsuits to 3.0 of modern suits is what makes the latter so capable of powerful flare - not the size by itself! But 3.0 is still not enough to, for example, make a Nesterov's loop using no engine other than gravity - for that, you need something closer to 10. Paragliders with L/D~6-8 can do just a tiny, not well-formed loop, while hangliders with L/D~10+ can do a much more pronounced loop; gliders with L/D=30+ can do a perfect circle very easily.

This illustrates a BASE jump in polar graph with various constant L/D's: jumper starts at the origin (zero speed) and the lines with L/D = 0.5...3.567 show how horizontal and vertical speeds change - higher L/D results in better natural planeout (i.e. lower min vertical speed, higher max GR):



So, while in both cases total speed is the same, 144mph (looks decent fast, right?), the pilot flying steeper terrain - paradoxically - will have lesser ability to detach than the pilot flying shallower terrain, because his L/D is so poor that he's essentially in a stall, while the second is at L/D 1.5, which has more "oomph" for flare. (although, of course, steeper terrain will drop down below the pilot faster)

Now, the right, safe(-ish) way to fly in this example is not at 144mph, but at much higher total speed, at the right-bottom-most region of the WPR where the slope intersects the WPR envelope, not the left-top-most region. This will give the pilot much much more kinetic energy to covert to potential energy when needed.

Also, it's better to fly fast with zero dihedral, not sweeping arms back, but instead achieving high speed by reducing AoA. If AoA is very very small, not only you're superfast, but you have more room for AoA to increase when you need it. If AoA is not small and you achive fast flying by sweeping your arms back, you leave little room for AoA increase.

These examples demonstrate the "polymorphic" nature of wingsuit dynamics: you can be flying in exact same configuration, what looks and sounds to you like exact same speed, what looks on video (even outside one) quite typical, but actually in very different (aerodynamically) flight modes with completely different margins of error in terms of detachability.

And this, I think, is a very important point to make and is the whole reason why I wrote such a long post. Not knowing this point is a trap which can lead many pilots to trouble, like it did with Eric.

This is the mechanism that can trap pilots in thinking that their flying is ok, because the visuals and hearing tell them that their speed is decent enough. But it actually is not.

Flying just fast is not enough, it's not enough to rely on just the sensation of speed, because we cannot intuitively (without instrumentation) break total speed into its horizontal and vertical components. It's important to fly fast HORIZONTALLY, with whatever vertical speed comes with it. The solution to this is to fly DELIBERATELY SUPERFAST, well in the right-bottom envelope of the polar region. Cannot fly superfast? Abort the flight NOW! Either peel off now while you can, or pull now if you're high, but do not continue into the line - it's now a zero-margin trap.

Eric, get well - superfast!

I think when people talk about 'flying fast(er)' they refer to the speed on a given slope. In that case total speed is linearly proportional to horizontal speed when slope/glide is fixed.
And since in proximity flying the slope is given by the terrain, the advice to fly faster or as fast as possible gives you the best ability to disconnect.

Not taking away anything of your theoretic discussion.

+1

It looks like the last right turn he makes is where there is a significant drop-off in speed. If he had kept diving to the left, he probably would have been able to make the switchback. He probably would have been flying with more energy if he had committed to flying cheese grater earlier and used the distance flight to the midway station to focus on building up as much kinetic energy as possible. It looks like he might have been flying slow there because he lost focus on performance and was distracted at comparing two flight trajectories.

It is also worth noting that flying aiguille is a shift in terms of how long the lines are. In my earlier flights I was making the mistake of eagerly flaring too hard when disconnecting from a line (especially cheese grater). It feels counter-intuitive to tell yourself to keep diving at the end of a line, feels much safer to just pop up (and is the lazy way out). But you'll get more distance and separation if you gradually change your AoA and do a slow, powerful flare. Flare too quickly and you'll bleed off a lot of energy for maybe 100-200ft vertical gain. It is also easier to keep the arm wings and grippers straight (look at backcam; no curvature in the arm wing), and thus more efficient, when doing a slow, gradual flare.

This is a mistake among beginner-intermediate jumpers that I've noticed since I've noticed myself do it. And in retrospect, it is something I've noticed experienced jumpers do very well. I observed this when I started doing lines that had me exit at relatively lower altitudes (exit line, fly for 5-10s, pitch, and have a 15-20s canopy ride). The consequence was power flaring and not pitching over where I want to land -- a few times I hesitated on the decision of wanting to keep flying near the peak of the flare so I could open above the LZ, and that resulted in linetwists. We have one line locally where folks exit low, and there have been a few instances of linetwists from folks who rarely get them, and I am pretty sure power flaring as opposed to a slow, gradual flare is the culprit.

It's ironic the impact the article has had. At my local DZ folks were talking about how Eric is such an idiot. But I am hoping the intention of the article was not for people to go "oh, that guy's an idiot, I'm totally doing things differently and am not him." That's what leads to people dying or getting seriously injured. The path to becoming a better pilot is looking for what mistakes you are making, not taking the easy way out and scapegoating the most recent mistaken jumper.

And if you are an experienced jumper, the path to building a stronger, safer community is to proactively reach out to jumpers in a positive way to pre-empt major mistakes, rather than ex post facto burning the witch at the stake. My ego doesn't want me to think that I could have ever have ended up being in as embarrassing a situation as Eric, but that's the easy way out -- you can cut all critical thinking there if you do not attempt to see the flaws in others as flaws in yourself. Or even the luck that you've had. In my case, perhaps I would have been Eric if I hadn't had the opportunity to fly with better, more experienced pilots in my progression.

Big thanks to Trent Conroy and Chris LaBounty for being experienced jumpers who did some two-ways and offered advice -- even sans coaching, flying with better pilots will illuminate areas where you are weak. Also, big thanks to Matt Gerdes, Mike Steen, Joe Ridler, and others who have helped organize WOWs for setting up a competition format that accelerates learnings on flight modes and is open to anyone -- everyone who flies a wingsuit really should do this competition format, it's easy to think you are great when you are the local dorkzone hero, go compete and prepare to be humbled.

I hope experienced jumpers' takeaway from this incident is not the easy, jaded "I won't jump with these new idiots," but rather "I should take some time to fly with some new folks and help them progress." Ultimately if we want the Chamonix ban to be lifted and not return due to another incident in the future, this is approach that needs to be taken.

Good points!

Just to throw in some more numbers as food for thought... Estimates from Google Earth and Eric's video (starting at 1:45 mark):

0-10s interval:
map length 452m
ground length 516m
total speed V = 516m/10s = 51.6m/s = 186km/h = 115mph
horiz. speed Vx = 186*452/516 = 163km/h = 101mph
vert. speed Vy = (186^2 - 163^2)^0.5 = 90km/h = 56mph
slope/glide ratio GR = 1.8

14-24s interval:
map length 380m
ground length 444m
total speed V = 444m/10s = 44.4m/s = 160km/h = 100mph
horiz. speed Vx = 160*380/444 = 137km/h = 85mph
vert. speed Vy = (160^2 - 137^2)^0.5 = 83km/h = 51mph
slope/glide ratio GR = 1.7


115mph/186km/h along the slope, 101/163 forward, 56/90 down does not sound particularly slow. Yet we now know that this is not fast enough, this has virtually zero margin. Just an unnoticeable 10-15% slowdown at the end of the line - and he stalls it trying to disconnect. I'd say this flight mode is somewhere in the orange region on the WPR diagram.

Wonder what others are getting from their videos or GPS? From the videos I've seen of the Cheese Crater, looks like many people are flying at similar parameters to Eric's.

How about this idea. Instead of building up the maximum speed before entering the line and then having a potential to slowly waste it by the end of the line... build up a "good enough" (GE) speed before entering and continue accelerating through the line so you exit it with higher speed than you entered it. Fly in such a way that you're continuously reducing AoA, while maintaining as efficient body position as possible (i.e. no dihedral, fully stretched, "leaning" forward to go steep and fast) to keep L/D as high as possible for the given GR dictated by the slope. Max speed at the end of the line with max L/D (given the speed, not the real max L/D) will create best conditions for safe disconnect and powerful flare. The acceleration will ensure that L/D will be higher than the slope GR, which is good for converting the energy into altitude (vs. decelerating, where L/D < GR, or constant velocity flight, where L/D = GR).

Do this "fast, accelerated proximity" (FAP in short ) very high above the lines, with all means of ensuring that you're not only flying fast, but constantly accelerating - roar of air, visuals, video analysis by waypoints, GPS and other flying magic . Only when you can do it with 146% consistency, start slowly lowering your flight. The rule must be, you always exit the line with higher speed that you started it - ideally, through smooth acceleration from GE speed to max possible speed at the intersection of the slope line and WPR envelope. This will probably be even more difficult to master than very steep and fast low AoA flight - it's kind of unnatural to accelerate -and- maintain constant GR, we're more used to "milking" our speed/deceleration to have constant, elevated GR, but once it's mastered, I think it will be the safest way to do proximity.

Everybody, FAP!

That's all very interesting but I still think he's an idiot.
He went too hard too fast and went in - all to get footage for social media (as he admits himself).

As far as the 'slow flight' is concerned, it seems like you're saying the same thing but in a lot more words. It seems like what you're saying is that he flew in a 'max glide' configuration for long enough to burn off the speed he needed to flare and save his life - which is essentially 'flying too slow'?

Regarding the compared video, in Eric's case I suspect he was a heavier pilot in a slightly smaller suit, so he would have a higher stall speed and needed more speed than them for the same safety margin?

With this sort of situation becoming the norm so will bans on wingsuit BASE at places like 'the Cheese Crater' as you aptly put it.

Illustrating FAP with numbers.

Eric's total speed reduced from 115mph to average of 100mph over 10s (so, at the end of the interval, speed can be estimated to be 85mph), so absolute acceleration is approx.

a = -1.44m/s^2

with components: horizontal ax = -1.23m/s^2, vertical ay = -0.74m/s^2.

As we know from Wingsuit Theory, lift-to-drag ratio is related to glide ratio via the formula:

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

where z is dimensionless ratio z = ax/(g - ay), g being acceleration of gravity.

We have z = -0.12, GR = 1.7, and thus, L/D = 1.3.

In this scenario, L/D is lower than GR (slope), because he's decelerating (speed is converted into higher GR). With L/D of 1.3, on WPR diagram, he moved along the 1.3:1 slope line from higher speeds (in orange region) into red region - low speeds, low L/D area - and thus got a stall. At L/D = 1.3 and these speeds, you have as much flaring power as a tracker - you can brake a bit, but can't peel off.

Now, the FAP scenario: he enters the line at 125mph, but over the next 20s gradually accelerates to 165mph.

a = +0.9m/s^2

with components: horizontal ax = +0.77m/s^2, vertical ay = +0.47m/s^2.

We have z = +0.08, GR = 1.7, and thus, L/D = 2.1.

HUUUGE difference. Disconnecting from the line not only at 165mph, but at L/D = 2.1 which has way way more flare potential than 85mph at 1.3. I think 165mph total speed at L/D = 2.1 is doable (and it's definitely not dihedral flying, but clean configuration with very low AoA).

Conclusion:

To survive proximity flying long enough, you better FAP.

I was thinking, would it be possible to execute FAP using clean (no dihedral, fully stretched) configuration, just by changing AoA? Intuitively, it seems that doing so (just gradually reducing AoA) would result in convex trajectory, and that's not what we want for FAP - we want perfectly straight trajectory with acceleration. And came up with a beautiful, simple result: to keep the three variables - GR, L/D, and acceleration a - constant, they must satisfy a precise condition:

a = g*(1 - G/L)/(G^2 + 1)^0.5

(here, I'm using G for GR and L for L/D for brevity)

So, in the above example: GR = 1.7, L/D = 2.1, acceleration must be exactly 0.95m/s^2 (which just happens to be close to arbitrary chosen 0.9m/s^2, or 2mph per second).

GR is dictated by the terrain, what about L/D? Why try to keep it constant? Well, because we want acceleration, L/D must be higher than GR, so in a sense, L/D is dictated by GR... that is, by terrain! By keeping it constant above GR, we ensure it does not drop down to GR, because then acceleration is not possible without losing altitude above the terrain. We try to maintain some constant separation between L/D and GR, just like the altitude between the pilot and terrain.

All this boils down to an interesting and not obvious conclusion: to execute FAP, one must start the line from the innards of the Wingsuit Polar Region (where compromised configurations live, such as dihedral, arching, collapsing wings, etc.), not from its envelope (clean, no dihedral, fully stretched)! And this means, start the line in dihedral configuration (but still, horiz. speed higher than max L/D speed) and gradually transition into no-dihedral config with very low AoA and very fast speed at the end of the line:



Can't wait to try FAP on a skydive! If you're interested, here's what to aim for: the trajectory must be perfectly straight (constant GR) and with steady acceleration, starting with some healthy amount of speed and keeping accelerating for at least 20 seconds. The GPS graphs should look like this: horiz. and vert. speeds vs. time are straight lines, steadily increasing; glide ratio is strictly constant, with only small (+/-0.1-0.2) fluctuations acceptable. Describe the mechanics of how you achieved it: dihedral, AoA, etc.

 
The ''Fap mode'' is nothing else but the transition from FigB to FigA in the picture (from Topgunbase site). If you find yourself in the ineffective dihedral configuration of the Fig B for some reason (to gain stability?) you should gradually transition to the Fig A configuration with zero dihedral by spreading you wings(just use that airfoil!!!) and steepening the AoA at the same time.

But you shouldnt be in the Fig B configuration at the first place, its ineffective(you are not using your wings! you are just falling sideways).
Dive towards the line with zero dihedral by modifying your AoA not your configuration.
Everything in the "polar region" is ineffective flying, use just your polar curve!

Flying with your AoA is not easy, you are much less stable and you get the unpleasant surprise of the "wobble" at steep dives(more airstream going over the top surface). You should first train that skill intensively in the safer skydiving environment.

Yes, I think FAP should be executed as the transition between Fig B and Fig A, although in Fig B the pilot has legs bent - perhaps, he's been f1.0cking too much, muscle memory stuck. Fig B configuration should already be fast enough and safe for disconnect; next second, he's only faster and even more safe to disconnect; next second... and so on. By the line finish time, he's built up tremendous speed and is in squeaky clean aerodynamic shape at low AoA, disconnects easily and shoots up the sky like a jet, finishing with a soft "go-n-throw" deployment.

The whole idea of FAP is two-fold. First, how to avoid slowly losing speed and getting into the trap. Every pilot knows from experience that it's very easy to bleed speed unnoticeably. We are very poor speedometers. When we use sound of airflow to gauge airspeed, we can think it's constant while it's actually slowing down slowly. It's hard to keep track of slowly changing sound. If we are presented with sounds of 120mph air and 100mph air at once, we can easily tell the difference; spread this change 120->100 over 20s or so and it's almost impossible to tell it's changing - until it's too late. Same with visuals. With trees, rocks, grass flying by so close, everything looks fast. Is it possible to detect a 1, 2, 3-mph per second slowdown? (like in Eric's case, about 30mph loss over 10s) The visual perception of speed also depends on distance from terrain - farther, it seems you're flying slower, closer - speed seems to be healthy fast, although it might be not. All in all, we're poor cruise control.

So the first idea is, if it's so easy to inadvertently bleed speed until it's too late, why not ensure that we don't bleed it by constantly accelerating? Remember movie Speed? The bus will blow up if speed decreases to 50mph. If we have a poor speedometer and never can tell speed for sure, why not steadily step on gas - if we're accelerating, we can't get any slower that we're now! The idea is to be proactive and constantly pile on more and more speed, this guarantees that we won't stagnate on the line.

And second idea came from Wingsuit Equations - if we're accelerating, our L/D is automatically greater than GR! GR is dictated by the terrain, it's a fixed number for every pilot doing the particular line. But L/D can be either equal to GR, when pilot is flying at constant velocity, lower than GR, when pilot is inadvertently slowing down (like Eric), or higher than GR, if pilot is intentionally speeding up. Higher L/D, combined with healthy speed, presents better ability to convert kinetic energy into potential energy. L/D - lift-to-drag ratio - is akin to coefficient of friction (or rather, the reciprocal of it, so instead of k=F/N where F is friction force, N is normal force, we have 1/k = N/F, just like L/D - ratio of the force perpendicular to trajectory to the drag/friction force). The lower the friction, the better and longer the kinetic energy can be converted to prolonged motion and even going up. Similar to skates/bike/rollerblades/etc. with lower friction - you can travel farther and even temporarily go up from initial speed. For WS BASE, this is illustrated by the colorful spiral curves in my first post: low L/D is like a pendulum in molasses - you deflect pendulum (give it some energy), but this energy is so overtaken by friction that the pendulum returns to equilibrium without any oscillation. High L/D is like pendulum in air - energy is converted between potential and kinetic efficiently, as friction is low, and pendulum freely does oscillations.

This second "idea" is actually just a serendipitous side effect of the first idea - not only we're insuring healthy speed throughout the line, but we get better L/D as a result! Well, thank you, Wingsuit Gods, we appreciate your generosity! (seriously, since the discovery of Wingsuit Equations and all the beautiful "side effects" of them, I thought many times that there's an Old Dude In White Wingsuit somewhere Up There in the Cloud, there are just way too many indications that it's all not random... Half Dome cut into a perfect vertical wall by a glacier? gimme a break)

Another positive side effect of FAP is that you're not in inherently unstable configuration of clean, superlow AoA 100% of the line - you only "touch it" at the very end - and oomph you go. On average, you fly the line with some dihedral, so you're more stable. Holding superlow AoA for prolonged periods is less stable and unrecoverable if something happens and you're close to terrain, for example, a bird shooting out of the trees in horror.

Now, to address
> Everything in the "polar region" is ineffective flying, use just your polar curve!

True. The innards of Wingsuit Polar Region are indeed, inferior to its envelope (aka polar curve). Polar curve is a "scan" of a fixed configuration through various angles of attack. Since airplanes are (mostly) fixed configuration (whatever variable elements they have, they use them to merely control AoA), they have a well-defined polar curve, and since airplanes are not controllable/measurable at AoA higher than the stall angle, and can disintegrate in the air if AoA is lower than that of max structural strength speed, their polar curve has a well defined start (stall speed/angle) and end (max speed not to exceed).

Wingsuits have virtually infinite number of configurations - from fully stretched to balled up; we can arch, dearch, fold wings, change dihedral from 90 degrees to -90; bend legs, bring knees up; turn head around; pick up nose, drink beer in flight, squeeze butt... even have an erection! Scan of each configuration will produce its own polar curve. Together, this swarm of curves will form some region in polar space. It's intuitively obvious that the envelope of this region will be the polar curve produced by clean, fully stretched configuration, and our AoA can change all the way from 90 (wingsuit in vertical windtunnel) to 0 (true headdown) without instability or destruction. So, the WPR is like an apple covered in chocolate.

Yes, it's better to only lick the chocolate on the surface (although, it's rather just one little spot on the surface dictated by the GR of the terrain). But not every one can be so precise, we know from BFL that even best pilots lost it and went all the way from the surface to the rotten left-top-most innards of WPR. FAP is an idea to start from not-so-tasty (but still healthy) "dishes" and crescendo to more tasty ones, victoriously topping off with a dessert of fine chocolate at the end of the line! It's the transition, positive movement through WPR that ensures the happy end. Unlike eating chocolate apple, once you lost speed, it's impossible to regain it without cratering. You can't just slowly accelerate from slow speed. But if you start at good point inside WPR and actively "swim up", you guarantee that you'll get to the yummy chocolate of the surface.

Anyway, so far this is just theorizing and I'm very intrigued how it will turn out in practice. At least, it shouldn't hurt to FAP on a skydive.

Here's an easy to understand analogy: canopy flight. From the physics point of view, the dynamics of canopies and wingsuits is described by the same equations - Wingsuit Equations. (except for fast dynamic maneuvers involving CG/pendulum effect, acrobatics and such.) Wingsuits, essentially, are nothing but very small canopies, with CG inside the canopy. So the familiar concepts of "front risers", "rear risers", "brakes", "flare", "plane out", "sink", etc. etc. can be applied from canopy flight to wingsuit flight. Heck, they can even fly relative!

The old school of proximity thought is to fly fast in dihedral (sweeping arms behind your back). In canopy talk, this is equivalent to going steep and fast by pulling both front risers and brakes (although the analogy is not perfect here: dihedral is less efficient aerodynamically like brakes, makes a bigger area of negative pressure behind the wing like brakes, but makes you move faster, unlike brakes).

The newer school of thought is to fly steep and very fast without dihedral - on front risers only. However, deep front risers make it less stable - canopy is prone to collapse, as the stagnation point is so close to the middle of leading edge that a little disturbance can catastrophically flip the majority of airflow from bottom surface to the top. Also, speed can bleed undetected more easily with wingsuits, as we don't have this easily detectable feedback of pulling on the risers, with wingsuits inputs are much more subtle and easier to slip. And if one was to pull on the risers more and more to accelerate, they will inevitably go steeper and hit the terrain. There's no way to just pull on front risers more and more and not to produce a convex trajectory.

With the suggested FAP method, we start with some fronts and some brakes (but still with enough speed to bail). Then we slowly release brakes and pull on fronts more - in concert such as to maintain perfectly straight trajectory (constant slope). Thus, we accelerate steadily and by the end of the line, we're very fast and clean - on fronts only, then swoop and flare.

By actively working with fronts and brakes at the same time, we proactively increase speed, vs. trying to keep fronts in the same position and unknowingly slowly letting them up. Proactive FAP vs. passive FUC (Frozen Up Configuration).

No formulas or graphs here, wow!

Yuri,
Very good work on this thread. I took a lot of notes. Please keep writing. Flying smart is the new 'cool'.

Richard

Damn Yuri, I love your posts! Thanks for taking the time to make em!

Ditto, and thanks again to Eric and TGB for starting it all off... their interview and this thread should be turned into a handbook for wingsuit flight. Some of the best stuff I've seen on the subject.

great info ! Thank you to all !

He failed to mention that numerous people (including many high profile jumpers and I) had warned him that he was flying way too slow and he was not ready for Chamonix...He slept in my spare room and I spent a lot of time speaking with him- I could see that the advice I was giving was just going in one ear and straight out again..... I even offered to take him to a 'safer' jump when I could see he was determined to go to Cham......He's a nice guy and of course I'm glad he survived. But let's call a spade a spade!- that was more than just stupidity!!!........and also- the article says his primary stow was intact.....even if his primary stow was intact, then his canopy was pulled out, slowing him down- then it was basically just the same thing that happened to Jonathan Zar. Why are people then calling this a nothing out impact??......all my shit was still in the container!


Reiner

From what I see on the video there was no pull, nor an intention to pull. So, that leads me to think that the container opened on impact. Any intel on that?

Hi Ronald, Yes!- that is exactly what I'm saying- his shit came out on impacting the tree- just like Zar- that would explain why the tree broke near the bottom when he impacted the top portion of the tree- if his pilot chute was pulled and the canopy came out in the tree.....with all the lines creating tension it wouldn't have necessarily needed to pull the primary stow to slow him down enough.....then combine that with the approx 30-45 degree slope....explains his injuries better. I think it takes more of a shock ( and resulting in more severe injuries) to 'bounce' the canopy out.....the question is was his shit out or in when he was found?- judging by the pics it was out- can anyone clarify?

well, that small factor about the canopy is REALLY important to know, Isn't it???
Whole 20+ pages Yuri wrote and post comes down for you to - was the canopy out or not?! - Bravo!
Canopy was not the subject of Erick action at all.
Fact that he survived was not subject of Erick action either. He was just LUCKY as well as you were lucky.
Yes - he landed his body in his wingsuit and he cut even bigger tree than you with his body , so he is better than you!
Was he stupid or not - Irrelevant as well, as by this analogy all people who make mistakes in flying ( or where ever else ) are stupid too .
No one dies in the smart way - never!
Remember that and stop attacking this guy.
He knows very well that he is / was slow.
Why , it is self explaining and common this days.

 
Eric is saying a lot of bs about people, including me, not speaking with him prior to his accident.....I just smell a lie, that's all.

How you keeping these days Robbi??...I see your making the Aladdin flying carpets suits now (isn't that what you used to call them)...... If you can't beat 'em, join 'em huh!


Reiner

I'm failing to understand your logic on the tree breaking near the bottom because of his lines being out? But that doesn't really matter because the portion of the tree that broke was 20 feet off the ground (and wasn't even in the first cluster of trees he hit), so I wouldn't exactly call that near the bottom.

Best estimate of his impact trail is 260+ feet. Canopy was next to him in a ball at his final resting spot, pretty sure the locking stow would've busted if he was dragging it the entire way... Face it, his wreck was more impressive than yours... If you can call either of them impressive.

 
Thanks for the information!.......this aint about who's crash is more impressive- or about braggin rights!.........I'm just interested in the truth!........I'm just reacting to Eric's claims that he wasn't properly informed about Cham. He is lying pure and simple!.....I met him 4 different times when he came to Switzerland and know his progression. Sure, he is a nice guy- and I liked him......and I spoke with him many times about being careful in his progression.... I invited him to stay at my place if he needed a bed- later in the year he did -we spoke at length about Cham- and I made it clear that it was a very bad idea to go there at his experience level!....I asked him about his flying- I warned him about his exit weight and the potential problems this may cause on a short start for a beginner pilot-I spoke to him about speed and energy management..... at that time he told me that he had just done his first real terrain flight at the Melchstuhl exit and had only made it over the lower forest on the talus.......I told him that this was a bad flight for that jump and the suit he was on......I expressed my concern that he wanted to got to jump Brevent the very next day!.......I told him my story....he listened- but I could see that he was determined to go anyway.....when I could see that he was determined to jump in Cham-I explained that there were many other awesome jumps that most new guys don't know about -beautiful ones not so far from Cham, that would be better and safer to progress on- I offered to take him to an easier, more comfortable jump.....he accepted!.....I packed my rig and made plans to take him to James Bond- just to give him a more comfortable exit with loads more height......and to take the opportunity on the hike to try again to persuade him not to go to Cham......but he stood me up!......(which actually pissed me off- because I had planned to take my wife to visit Patrick in hospital again that day in Annecy and then Patrick was suddenly moved 1100km away and my wife missed her opportunity to visit him in hospital)........the next day I got an apology message saying he had just jumped Brevent and he had a multiple airgasm ......He was jumping with Alex Miziuk and all the cool guys in Cham........at this point.....I stopped being concerned and quietly knew he would make it to the list.......After his accident, I met a bunch of people who had said that they had spoken to him.......(I could mention names if you want)

.....Now, I'm reading his bullshit story, about how he didn't have proper information....and he is basically calling me a liar on the internet....Ok-, so no big deal- but it does get this kind of reaction from me....And it makes me start to ask questions. No one else seems to be asking- they just jump on the sensationalistic band-wagon.

.....Aren't you people sick of the unneccessary fatalities??......why are the newbies not learning from the mistakes of others??......Newbies are so focussed on end game- they ignore the old guys in the corner- and only pay attention to the guys in the spot light who are on the videos.....it's the blind leading the blind now!......Doesn't the community realise that one of the main reason for the now common explosion of summertime fatalities is because of this sensational bullshit and exaggerations of the truth of what is really going on!....The wing suit races and big events that are looking for sponsors and media coverage will be happy to put your name in lights and capitals saying 'SO&SO IS ONE OF THE BEST PILOTS IN THE WORLD'.....It sure does feel good to see your picture in a newspaper on online under one of these slogans!.....and maybe if your hang around in the group with the celebs and start jumping the 'hard-core' stuff and get away with it- perhaps you can start to fool yourself and start believing it!...the truth is you cannot go from putting on a wing suit to being an expert in 1, 2,3 or even 5 years (Well, there are exceptions with the right training and progression- but I'm not talking about those- I'm talking about normal people).....Suits are always evolving and we simply can't keep up....People who have been around for a while, know that we are all test pilots now.

The truth is Eric is and always was a novice pilot who should never have been on any exit point in France. He chose to ignore the sound advice that was presented to him by many different experienced people and now he is lying about it. So, - instead of calling him a hero- let's call him a dumb fuck liar!......I bet if we start tarring and feathering these idiots, we can better secure our sites!....seems like all they care about is their social standing!


Used to be that the base community regulated itself.....those days are long gone- and those people are mostly dead now!....Used to be that gear manufacturers screened who bought their stuff.... there are plenty of meat-missiles lining up to buy all of it!- there is a long waiting list for all the gear......why can't we go back to those day??............Look at what is happening in Chamonix!...if you have ever been on an exit with someone, who in the back of your mind you thought was not ready- and you kept quiet- then a piece of the blame is on you!.....We are all responsible!


Base-jumping and wing suit flying should not define your life!- instead let it enhance your life!......We are doing something pretty fucking amazing! and we have the opportunity to face death head on and choose what is really important in our lives!.....that equates to less regret in our last days!.....not many people get that!


Lets keep it real.

Reiner

 

And there, just for a second, I thought people wouldnt jump for money, but for the fun of it. Guess I was wrong.



Yeah, that shit didnt even fool you too!

 

Dude....I see your a newbie.......Listen- when you've spent as long as I have jumping and not trying to make money....then, if you get to my age with nothing in the bank- you won't easily give up on an opportunity to make a decent amount of money!

...I'm just trying to do it in a way that doesn't affect my integrity.

...my advice to you if you have tunnel-vision on jumping, is to not burn your bridges when it comes to real jobs...the money in base is reserved for the 0.1%. -don't be fooled!

Peace.

Reiner

Dude... I see you're a newbie like me... Listen..
Please just go away. This used to be an interesting and potentially educational thread until you started throwing massive amounts of stone in the glasshouse we all live in. I wish you the best regarding your film project. Look forward to seeing it someday. In the meantime, please don't fill this thread with thousands of more words that we learn nothing about wingsuitflying from.



Edit: Could a moderator split the thread to "Reiners rants about how to properly crash your wingsuit" so we can get back on topic here. Yuri; keep it coming!

I second this notion.

 

I've said all I have to say.

....oh- just one more thing!......Jt....Next time you shit your bed in the Horner after a party- you might want to tell and tip the staff! ....my wife had to clean it up.

Reiner.

From what I just read from you, it seems your wife has to put up with a lot of shit

Sounds like a personal problem really. Has more to do with your failure to plan.


Too late. Already done.


Are you a "life coach" now or something??


So you're saying you're the 0.1%??

Love the Ego's in the sport such a shame BJ.com turned out this way ...

Never gonna change

LOL you know reiner1 this is no less than the fourth time i've (over)heard a shitting the bed story from you with now four different people as the punchline.

gotta ask Bern why she thinks the horner is such a hot spot for nocturnal bowel movements, or maybe its just a particularly abstract metaphor you like to use.

Yuri,
Your speed analysis is great and very well explained, but in Eric's case, there are 2 important variables to consider when comparing to the orange suit video (Sam and Nate?)
1) Eric was flying a V-Race (edited to change from V4) ... lower performance capability than the prototypes Sam and Nate(?) always get from P-Fly. Eric's suit has less stall margin at the same speed
2) Eric is huuuge... 89kg. Plus his stash bag is the heaviest I have ever lifted. He jumps a full weight rig with full-weight canopy, 3-rings, saddlebags, all the options. I am not joking, I swear his stash bag weighs 13kg. I picked it up from SAR in Chamonix. So his flying weight is easily 100kg! By comparison, Team Orange are much smaller guys flying ultralight-weight everything, probably even Vectran linesets.

So...
1) Significantly higher flying weight AND
2) Older lower performance suit.
Combine this with flying at the same speed according to video = Eric had significantly less stall margin compared to Team Orange. Not to mention significantly less experience.

The rest of your WPR discussion is amazing... enough to make my head hurt, but I love that our sport is starting to take the technical side of wingsuiting very seriously.

Flying smart is the new 'cool'.

Richard

Richard,

These are very important points that should be taken into consideration. I know well from experience that V4 has lower capability to dig out, it's more sensitive to having the perfect speed - and once you lose it, the transition into "limp mode" is more deep and less recoverable, compared to more "mattressy" suits. And wingloading (as mentioned above, wingsuits are very much like very small canopies, exit weight divided by surface area is as important in wingsuits as in canopy flight) ... well, nothing demonstrates the effects of wingloading as clearly as our jump together a few years ago - the Mighty-Meaty Missile here is ~260lbs (118kg) exit weight in V4. Given other equal parameters, the sustained speed is proportional to the square root of wingloading. If Eric is ~20% heavier (but same size) as other guys, one can expect ~10% faster speed. Even in the same suit, he should have been ~10% faster to maintain the same margin, let alone a smaller suit. But we should remember that we are poor speedometers and from jump to jump our speed can vary quite a bit - same guys in a different video fly 10% slower, almost a full second slower in the first 10s of the line than Eric. This means that these margins should be upped to allow for variability.

I totally agree that Eric shouldn't have been flying this line this close, ~200ft above - maybe, but not like this. That would be "flying smart". Flying high above the terrain, but matching its slope; trying different speeds and disconnects from different points of the line - from very beginning to the end, and observing the "peel off power". Thinking. Analyzing video waypoints, GPS data. Thinking more. Losing sleep as your brain continues to think about all this. Test, rinse, repeat. We need more articles and especially educational videos where top pilots demonstrate safe methods. One can't herd the BASE cats, but even a yahoo who watched Graham's videos and got too eager to fly like this, will inevitably stumble upon educational video or two - if there are many of them and they're interesting - and use that thing inside the helmet.

First thanks Yuri for all your energy to demonstrate that flying a wingsuit need a good learning and knowledge and not just 321 cya

A manual of good flying will change nothing when at the begening you choose the wrong way and don't respect the minimum of safe rules of that sport.

One rule is simple: less ego = less accident

What have change in flying a wingsuit between Loic Jean-Albert in 2005 and Grahan Dickinson in 2016? In fact nothing really... technics, skills, dare, bravery are the same. Just the wingsuits are differents, more powerfull.

So yes all that (ego) race to the craziest image will continue to make more and more accidents.

I was very surprise that no "top wingsuiters" will come here to explain how they fly... I know few wingsuiter that use GPS to develop their own flying curves to progress. Generally they use that for opening some news exit and safe their margin at the start and for the line glide. Most of wingsuiters only "feel" the fly or copy what they saw but don't use the knowledge of "physics" for how to fly. This is a big difference. There is a lot of empiricism in this sport and in the practice and in the advance. Flying in the slope need more balls than brain... and it works by trial and error. Confidence with the suit gives "bravery" and sometimes "stupidity".

The only way to be a good and old wingsuiter or BASE jumper is to be safe, to think safety first, being rational, with the best knowledge of all technical aspects and it is always time 1 second before the push to go back home and stay alive. And this is the best educational that should be shown.

Take care peace

Jerome

what is wrong with 321 c'ya?

 

WTF??....That is complete bullshit mate!......nice fucking try to discredit me!......I don't make shit up!


Reiner

Right here in this thread we have a highly technical and interesting discussion of a recent incident, a guy who went in and survived complaining that another guy who went and survived didn't go in as hard as he himself did, and an argument over who and how many jumpers defecated in a specific bed at the Horner.
It could be worse.

Yes you could be reading American election news coverage.

Laugh of the day so far - thank you :)

Yuri, thank you for sharing your knowledge with us again and again. I learn so much from it!
Branco

I rarely get into the issue of where BASE jumping is going since I started Jan. 1, 1982. BASE is in pretty good shape if you ignore wing suit incidents. I love the footage and the fact that it's the closest thing to human powered flight we have. I was lucky enough to be invited by a good friend, Iiro., to be one of the judges for the first world wide wingsuit grand prix in China in 2012. I met some great guys that were all super skilled. Since then, 4 of them, that I know of, out of 16 competitors that year are all dead from wingsuit accidents. Need to do better self regulating or the sport will lose some beautiful sites. Maybe more of the leaders should stress flying a little higher and requiring more air time for some of these newer jumpers who really have not had enough real air time to develop faster instincts. Just a thought from an old timer.
Rick
Director, USBA
38

For those who missed it, there's my app called "Wingsuit FAP" (available on any smartphone) that implements this idea. Perhaps, the best way to practice FAP is with clouds - find some feature on a cloud that mandates a steep line to it (similar to proximity slopes) and try to fly along this straight line (constant glide ratio) while continuously accelerating. Any feedback (in Technical forum) is welcome.