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Comment by Zuider | Hacker News Reader

This seems to be the key paragraph:

"Most beginners who die appear to be making variations of the exact same error, according to Webb. “They jump off a cliff, get flying, and for some reason there's just this human reaction to try to hug the air like a big, gigantic beach ball,” he explains. “By hugging air you feel as if you're creating or catching more lift than you actually are. What ends up happening is your suit can only grab so much air, and it starts to stall. When it starts to stall, it loses lift, starts to drag, and then, splat."

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I was a little surprised by that quote since this is something you learn in skydiving class, and everyone's getting basic skydiving certification in order to start BASE. You learn on your first day that if you hug the beach ball, you will flip and fall with your back down. The easy to remember analogy is a falling leaf -- leaves always fall concave (edit I mean convex) side down; cupping the air is completely unstable.

Anyway, you're right, it's an important piece, and I'm sure the hugging the beach ball thing might become an instinct response that overrides your training and happens very quickly when it becomes obvious that you're going to collide in 0.5 seconds. But, the article also immediately follows that with 'but that doesn't explain why the best flyers are dying'.

The singular reason people are dying is because they're pushing the boundaries of proximity flying, not because beginners are accidentally stalling once they're too close.

> leaves always fall concave side down

That explains it. They fall convex side down...

Easy way to remember: a cave is concave.

And it would be very vexing to try to enter a convex cave. Science class mnemonic!

Convex! I meant convex. What a total brain fart. More coffee!

Or like the diheadral angle of airplane wings, anhedral ("negative dihedral") isn't as common.

https://en.wikipedia.org/wiki/Dihedral_(aeronautics)

> "this is something you learn in skydiving class…You learn on your first day that if you hug the beach ball, you will flip and fall with your back down"

This is true of the first 20 or so jumps, before achieving your "A" licence or equivalent: you're taught a belly-down arch.

When you advance past your A-licence, and especially when studying for your FS1 qualification (Formation Skydiving), you're taught variations of that arch, which are much flatter and even concave, in order to adjust fall-rate, so that you can stay in formation, with everyone falling at the same speed.

You also figure out very quickly that those slower fall-rate body positions are much less stable in the airflow…but that's why we practice.

> The singular reason people are dying is because they're pushing the boundaries of proximity flying, not because beginners are accidentally stalling once they're too close.

Well put. As noted in the article, the margins for error (esp in wingsuit BASE) are becoming ever tighter.

For pilots instrumentation was useful. Are there airspeed indicators for wingsuit fliers and do they have stall speed estimates?

With modern Bluetooth it feels like it ought to be possible to design a wingsuit HUD to help with this.

With all due respect, there is no way in hell I would trust Bluetooth with my life.

It might be better than no sensors.

or it might not be.

> "Are there airspeed indicators for wingsuit fliers"

Yes: there are devices that can be mounted to skydiving helmet, and provide audible feedback (using different tones to communicate information such as airspeed). FlySight is one example.

"Audibles" are common practice throughout skydiving: usually two, mounted inside the helmet, next to each ear. They're usually set to beep at certain altitude thresholds: e.g. 5000' (break away from the formation), 3500' (deploy your parachute), 2000' (cut-away and deploy your reserve, if your main canopy is malfunctioning).

The GPS devices have to be outside the helmet in order to receive signal, and they're typically used for communicating performance data rather than safety alerts.

> "it ought to be possible to design a wingsuit HUD"

Recon announced their Flight HUD in 2012 [1], but I don't know whether it succeeded as a product. I don't know of anyone using it.

[1] https://www.engadget.com/2012/10/18/recon-instruments-offeri...

Not really a key paragraph. The article states that jumpers of all abilities are going in (dying). This is just one possible reason related to novices.

The article states that stalling the suit is the primary reason for novice fatalities. As the sport becomes more popular, the majority of new practitioners will be novices making mistakes that an experienced jumper would not make.

That's an interesting point, which has a fairly obvious solution: train wingsuiters to find the stallpoint - and even stall their wingsuit - in controlled conditions, where they can safely recover from a stall.

Can they really recover? There's really no margin for error when they're a couple of dozen feet off the ground.

Train while jumping out of aircraft, not off cliffs.

Please, name me one person who started base jumping off a cliff, and not jumping out of an aircraft.

While you're right that it's not very common, I know at least 3 (non-famous) people who did that. BASE and skydiving are pretty separate communities and there are a lot of people who make friends in base from cross over in things like climbing or snowboarding and don't do skydiving.

Source: am a skydiver/base jumper

It's discussed in BASE-jumping forums, mostly for its historical value, and to answer the people who ask with all seriousness: "How can I learn to BASE-jump, without bothering to learn skydiving first".

You'll also see it referenced on the websites of places that run BASE courses [1], where it's repeatedly acknowledged that it has been done in the past, but it's now seen as a reckless practice.

You can still find people that will teach this way, but for the most part, it's underground, and described as a "deathcamp" [2][3][4].

[1] http://base-book.com/skydive-to-base-jump

[2] http://www.basejumper.com/Articles/Getting_Into_BASE/Number_...

[3] http://www.dropzone.com/forum/Skydiving_C1/General_Skydiving...

[4] http://erikroner.com/242/

The same is true of pilots. To land a plane you basically have to fly it right on the brink of stalling, and if you accidentally stall it a few seconds before touchdown, you're in big (though hopefully survivable) trouble. So it's very important to learn to recognize how the aircraft behaves in that transitional regime.

Likewise, the idea here would be for wingsuit pilots to practice stalls and recovery while skydiving at a safe altitude. That way, when BASE jumping for real, they can recognize and prevent stalls before they happen so that recovery is unnecessary.

A pilot can correct by giving more power. Someone in an unpowered suit with ~3:1 glide ratio starting to recognize a stall while flying over terrain is already dead.

Can you train them over water, so the stall is not fatal?

Train out of an aircraft…exit at 15000', and train down to 5000'. That would give plenty of time (and altitude) to recover from a stall, and safely deploy a parachute.

Sometimes they can, but I wouldn't count on that happening reliably.

https://www.youtube.com/watch?v=1hKhofOF_zo&t=120

Wow, what a video.

"You know, fear is a super-important thing now. And without fear, you will die."

"I'm actually pretty happy this happened. I think in the long run it saved my life."

Mind you, he doesn't leave much margin for error in his come-back jump!

They could practice stalling via jumps from an airplane to get a feel for the limits of a wingsuit. As the article states, wingsuiting should be the last stage in a progression which begins with skydiving, not the first. Beginners are taking shortcuts on the road to necessary experience.

The possibility of stalling should be obvious to anyone who has flown a kite or thrown a paper airplane. Inexperienced wingsuiters just seem to forget it. They are lured into trying to achieve the illusion of lift whereas an experienced practitioner would maintain speed.

People fly at max glide too close to terrain which leaves them with no options. If people instead flew fast, they could transfer that speed to lift if they find themselves in the corner, but if you're at max glide you can't really do much.

Of couse, the main problem is people not flying within their limits, or giving themselves a good margin, but that's proximity flight by definition.

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