Could you survive this?
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- Опубліковано 21 лют 2023
- Falling on static ropes is dangerous they say. It sounds painful, but how painful? We tested semi-static nylon rope, a very static polyester rope and a high-tech super static abrasion-resistant rope in the drop tower. Spoiler alert, some would kill you and that's only a fall factor of 0.3 or falling 1/3 the length of your rope. Falling with a fall factor of one (fall 5 feet with 5 feet of rope out) can break the rope, which still kills you.
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You're not supposed to whip on static ropes
01:23 What force is ok?
02:06 Fall Factor-ology
03:24 Dynamic Rope Test
04:19 Semi Static Rope Test
06:06 Super Static Rope Test
07:55 High Tech Static Rope Test
09:05 Know how much it Hz
Our data is on our blog www.hownot2.com/post/static-whippers
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What happened to the other channel? I was looking for the awesome intro, and I get this instead.
The Department Of Redundancy Department fully supports your usage of "hz per second"!
Back when I started out in electronics that would have been "cycles per second per second" or "cpsps." Then they took away centigrade and made it Celsius and cps and made it Hertz. That hurt.
That would be a correct unit to measure how fast a frequency is changing.
@@angrybirder9983 how derivative
I think the Department of Redunancy Department is out of their jurisdiction on this one. That's a valid unit of measurement, but used incorrectly. So the Department of Incorrect is taking over the investigation.
Yeah.
Not at all a correct unit of measure as used here.
I love how how y'all really do the math and then also demonstrate to see how it compares. I think you did a great job explaining the myriad of variables like fall distance, time, rope length, additional slings / hardware, rope specs, and type. I also think y'alls scientific method is very good and thoughtfully executed. Great video!
I would love to see full-on research papers on these topics for those of us who are more academically inclined!
Thank you for bringing up the sample rate point, as some one that used to break stuff for a living it's good to know you are fully understanding what's going on with your testing!
Measuring stuff is difficult and a very huge part of physics and engineering. And those little things matter so much.
As an example, i had a client with double head circular saw for cutting windows and door frames (two cuts at the same time). Most cuts are 45 degrees. And to cut the proper length, you have to insert the exact width of the part, machine will slide heads to the proper place and make the cut.
And he claimed his saw was not cutting proper lengths with angle cuts. Interesting thing was that straight cuts were perfectly in tolerance. So i asked customer what width he is putting into the computer, and he said - the correct one, from the spreadsheet. The problem was that parts were also painted... and thickness of the paint was making a couple mm error in the length of the final product. And spreadsheet was giving dimentions of bare material, without a paint.
The term you're looking for is "Jerk," in math speak it's the second derivative of velocity. In other terms, acceleration is how fast velocity is changing, and jerk is how fast acceleration is changing. The longer the amount of time HELD at an acceleration is actually WORSE, but the longer the amount of time taken to reach that peak acceleration is better. Your body can handle HUGE accelerations for tiny amounts of time, as it doesn't change the relative velocities of different parts of your body very much.
Wow I guess I do math more than I thought
@9:54, some excel beta:
If you are looking to sample from the largest in your loadcell, excel has LARGE() and ROW() to help identify this (the syntax for sheets works differently).
That you can plug in your array, lets call that A2:A100000 into:
=LARGE(A2:A100000, ROW(1:N) )
This will return the N largest numbers.
But wait! There is more. You can find the mean of this sub array.
=AVERAGE(
LARGE(A2:A100000, ROW(1:N) )
)
I am super impressed you learning digital sampling empirically. You will hear things like “Nyquist” frequency etc. but you are learning by doing.
This is just the video I've been hoping for! I use a semi-static rope for TRS, typically with a single device such as the Taz Lov 2 or CT Rollnlock, and backup knots. I've often wondered about just how unpleasant my day would become if I fell a few meters to the backup knot. It should be fine, but I'm still hoping I never have to find out.
Keep up the science'ing my man, you're doing a great job!
Ive never been rock climbing and dont think i ever will, but i find your videos incredibly interesting and fun to watch! Keep up the good work!
I used to work in the elevator trade / lift engineering and your drop tower reminds me of an “inside joke” that goes: If you ever fall down the hoistway, grab the end of the electrical cord and throw into the hoistway to entangle on something.
This one has me laughing along with great info I've always wondered about. Thanks for all you do!
dude this is one of the best videos you’ve made, i love it!
Excellent presentation and explanation! Love it.
This is so important! Thank you for sharing 🌻
Would love to see some arborist rope tests, xstatic,drenaline,tango ivy, Cheryl bomb just to name a few. love the channel
Look at you getting all snazzy with produ ction value and such. Love it Ryan!
Idk if you guys upgraded your camera, but the filming quality of this episode looks great!
Can't get enough of this!! Great content
Super interesting info on the sampling rate, keep up the good work, this stuff is very cool
I'd love to see drop test results on one strand of double and twin rope !!! Thank you again for your work
Your vids are getting g way better, Ryan.
At 4:10 you mentioned the difference between steel weight and body in fall tests. I just read an alpine safety classic book by Pit Schubert (it's German, so hard to recommend). There the Author mentions that the difference between testing with steel weights and a real body is about 50% (at fall factor 1). That may be an interesting topic for you to explore. Maybe you could even come up with a better test object than a steel weight. Let's say some sandbag with a harness on or something.
What fall length was that for ? I can't believe it would be the same for 1m/1m vs 10m/10m (both FF1).
@@serges201 in the book it says that a steel weight will generate a 50% higher impact at fall factor 1 for the same height.
@@jimihenrik11 does the book give any data? Reference any studies? 50% sounds like a guess rather than an actual tested number.
Especially given the forces involved, a few percentage points can make a big difference, so rounding to 50% isn't good practice and it doubt it was exactly 50.
I'd also find it a little hard to believe it's that high of a difference. The human body is mostly water and does have an ability to absorb forces but 50% is huge.
The concept makes sense since a body will flex and slump to take some of the shock out as opposed to a steel weight which does not flex or slump over a harness, taking some shock.
Interesting vid. Thanks
A lot of work and thought on this one - makes me want to carry an extra Volta or other fully dynamic backup. I'm too old to shake off a "semi-static" whip of size. That 700 footer was awesome to see! Yeah, the sampling rate and true anchoring methods add credibility to the peak no.'s. 👍
great job big no doubt hope Ur channel grows huge I once broke my back in 7 places in a 30 to 35 foot fall and slightly over ten yrs later feel like I'm recovering
Really cool video!
I just love yours sciences' brow!
great video. thank you
so well done!
I would love to see a test where the first "piece" breaks or blows at a certain force, recording the force on a piece below that. Probably a nightmare to set up as a repeatable and comparable test, but I always wondered what the numbers are.
Safety harness gear have this part of sown rope which is supposed to break in case if a fall and lessen the peak force when falling in static rope.
Might be interesting to test how well those work!
Climbers have a similar thing (Yates screamer), but it's more to protect gear placements. Maybe throwing one of those into your system could make leading with a static rope in a pickle safer?
Thanks!
Hey Ryan (and all others). I unreservedly apologise for my brief and unhelpful comment on your video about sample rate all those years ago. No excuses. Keep up the great work. Richard.
Thanks. I appreciate that.
Love the intro man it was gold
This video is hilarious lol
Does using a more static rope increase your hurtz?
Love your channel. And I think you should do a collaboration with that "someone" who left a comment. Both of you are doing wonderful work.
I have that same yellow with orange/green tracer dynamic 9.8 Sterling rope. Everytime I bust it out at a crag someone has too make fun of the color lol.
I’ve jumped off a bridge with static rope ( one strand 5’ longer in a combat repel exercise in the military) - I survived, but my back still aches when I think about it…
What your looking for as a metric for "bone breakage" is impulse (average impact force)! "impulse = mass * change in velocity" so if you're falling at x velocity and stopping to 0 that will give you a fixed term for the impulse of any one person's mass. This is basically the change in momentum the person will see across the fall. Also "Impulse = Force * change in time" so if you increase the time taken for the momentum change, you decrease the force on the person's body.
I may not have enough knowledge about this, but isn't this just force with extra steps?
@@therflash sort of but force isn't the full story. It's easier to think of it like this, saying peak force is like saying i went 100mph in a car. Factually true, but if you got to 100mph in 30 seconds, you wouldn't feel much. but if you went 100mph in 1.9 seconds, your stomach is gonna be in your throat.
@@therflash Force is change of impulse per time. F = dp/dt
are you still working on testing for factor 1 and 2 falls for multipitch id love some info on the forces and dangers on harnesses bolts and other gear as thers no information on it
I loved the Hz discussion.
Have you done tests involving blown gear? Like what happens if a piece blows during a fall and you fall to the next piece
If you have to climbing on a static, put the belayer about 50ft away from the base of the climb so you have way more rope in the system. This is the same on a second pitch, make the hanging belay well below the anchor
Not sure if you've done this; I'd love to see a video on the force seen on the climber and on each piece of gear when sequentially blowing trad gear. At 7:00, you say "you would blow that piece of gear and fall on your next one, generating even more force." Maybe I'm not correctly understanding what was said (and maybe it also only applies to static ropes), but I would think the first piece of gear would see the greatest force and each subsequent piece would see less since the force of your fall is being partially absorbed when the gear pops (i.e. assuming reasonably closely spaced gear).
Can you tell me more abot the difference and value of a static rope vice a strap and how to properly empoly straps (knotting and stiching teqinqes).
I would be interested in a test on the Petzl Rad line … I used it for glacier traverse and falling in a crevasse with a static rope!? What happens !
This makes me wonder if I should use dynamic rope for my personal edge kit as a technical rescue tech in a large regional system.
Would be interesting if there are any fibers being developed with long delta-t ooblek or reverse ooblek type effect for rope being developed?
Recently got myself a static rope which I intended to use to start lead climbing. Guess I'm going to need to buy a dynamic one cause I like my back.
I love the personification of the UA-cam comment section.
please please try strength test on dyneema rope from hercules ropes ! wanna see how good they are !
Arborists climb on ropes that are super static. We really try and stay before 2.5%... all of our elasticity comes from rope in the system and dynamic flex in the trees we use as anchors
the 23 Hz isn't really right you need double the sampling rate of the frequency contends of the pulse. So the best way for you is to over-sample a lot to make sure not to miss the event. This is like deep EE. Cold you provide the raw data(like shown in the video (the csv or excelsheet)), so we can determine the actual frequency of the fall. This is a realy fun data acquisition problem .
This. More sampling is best here. More data better. If you want to catch a 20hz signal you MUST sample at 40Hz a a MINIMUM. Look up Nyquist. Tat 550Hz for the fall factor 1 on the drop tower is wrong. It actually needs 1100Hz to catch, again, per Nyquist. There's some complex math in here, bare knuckles EE stuff, but it's real.
I thought their methodology was pretty good. And 40 is almost double 23. I'm guessing they got very very close. You could probably do some interpolation and get a bit closer still.
@@tomgnyc it was super good enough!!
This exact problem is solved in audio engineering, it’s called Nyquists law, you need to sample at 2x the fastest signal you’re measuring
Worst case scarily would be a square wave where peak force lasted for t seconds. If you then sample at 1/t you’d always pick up the peak (well - I’d recommend 1/t*1.00001 to play it safe). Don’t forget, we’re not trying to reconstruct the square wave (which would require infinite sampling) only to pick up the maximum (which requires less sampling than a sine wave)
good job
As a canyoner. If it’s all you have, it beats pancaking…. If it’s an emergency situation and you need to escape, you will die if you stay where you are, you can free climb and die if you fall, or you can climb trad with static & maybe end up with life with a potential spinal cord injury. I’ll take life, even if it involves tons of crappy stuff.
it's crazy how close those peak load numbers are to rope's mbs (with knots) - you barely have x2 safety factor. So basicly its dynamic properties, whatever they are, is the only reason it can survive a fall on it
I don't see any tests for the Kong Energy Absorber. I'm curious about how it would work for lead rope soloing or some such.
I would love to see some tests geared more towards saddle hunting. Most climb with static rope and your anchor point is in some shape or form girth hitched onto a tree, this means while climbing up, your tether will be around your knees or feet and I’m curious how a fall like this would be
On the 5 by 5 feet versus 50 by 50 feet, I would wager the 50 will show up slightly less force due to aero drag. But I hope to be pleasantly surprised when you post that vid.
On a five feet drop you do not yet reach terminal velocity, your speed of fall will be faster after 50 feet fall
@@dmitripogosian5084 You do not reach terminal velocity but enough for aero to start having an effect.
And as speed is nowhere near the velocities where it starts to affect results on impact it should be the same.
To understand this I'd recommend doing the math that results in the fall factor equation and not the fall factor equation as that is a simplified version for climbers that should never do complex math while hanging from a rope.
So weight falling in gravity suspended by a rigid rope and spring system, preferably formulaic without values. And you can ignore aero at first and include it later to see the difference.
@@dragoscoco2173 So, neglecting air drag. I fall from height H equal the length of the rope L, My kinetic energy when rope starts to stretch is mV^2/2 = m g H, is equal to 1/2 k x^2 where x is the maximum stretch and k is spring constant. So we get maximum stretch being equal to x^2= 2 mg H/k. However spring constant itself is inverse proportional to the length of the rope, which is height of our fall, so k ~ 1/H., and we conclude that we stretch is proportional to height x ~ H. But the maximum force is F =k x ( Hooke's law), so F ~ x/H and is independent on fall height H. But if we take longer fall, kinetic energy will be a bit less than mgH due to air drag, so x and force will be a bit less. Is that what you mean ?
@@dmitripogosian5084 Pretty much this. As usual everything is a bit more complex in reality but it should agree to experimental results quite well. Nice work. As to things hard to predict and compute I find that rope has damping properties (never specified) and those are sometimes speed dependent, also they do max out at some point and change the properties of the rope due to temperature.
What if you were to whip on the Imlay canyon fire with some form of shock absorber?
Bruh the start lol
Great that technology has advanced, since the “old days”. Fantastic equipment out there.
I'd love to see testing like this, but use an ATC with a person holding the brake hand (with a belay glove to prevent hand burns) for the belay device instead of the Grigri. Because, I don't use Grigri for belaying lead climbing (except on slow aid climbing pitches), and I would never use a Grigri for lead belay when I had to lead on a "static" rope. When I have led on "static" rope, I made sure my belayer had the bare minimum belay device friction to get the job done (like a figure 8 in "sport" mode). BTW, for short falls on "static" rope, body compliance makes a big difference in peak force, but you already know this when you did your short falls on slings connected directly to bolts.
Nice Sprat t'shirt!
What about static ropes like the petzl RAD/PUR lines, especially compared to something like the Edelrid rap line which is designed to do the same thing but has a "dynamic reserve".
Or Beal Rando!
Would love a video discussing what happens to someone in a harness when they are subjected to various amounts of force. Like, if my harness is rated to 22kN, what would actually happen to me if I experienced a force of 22kN on my belay loop? I realise it's not something you can feasibly test, but maybe you could talk to someone who knows physiology…?
Ur back is not happy
But you are not supposed to take falls on a static rope. You are not supposed to do that. You are not doing it right. It's dangerous.
wait how can you fall twice the distance of rope you have in the system? like how is that possible? (can you provide an example?)
Have you tested impact forces on different materials? For example your non-human test was a hunk of metal. what forces do you get with equivalent masses of bag of sand vs a human? If the sand is more similar (I imagine it would be) then non-human tests should be done with a bag of sand, no?
2:49 back of the envelop physics backs this idea up. the kN you impart on the rope are going to be a direct result of how much acceleration you got before you "hit" the rope. the longer you are in free fall, the larger the force for a given mass (your body). but it also seems that how much rope in the system plays a huge role too, which seems to be why people talk about the factor so much. a short length of rope getting hit a little bit hard seems to be about the same "safety" level as a very long piece of rope getting hit very hard. this makes sense because the longer the rope, the more stretch, and the more time the rope has to slow you down while stretching.
Can you test some ferrata gear?
yah ouch....
fell about 10+ feet in a swiss seat . hanging from a piece of sta-set x. has very low 2 percent stretch.
peed blood for a month.
It’d be fascinating to see the static lines effect on the human skeleton with a test dummy
I imagine that the difference would be much less notable/scary on a dynamic belayer.
All I use is static rope… never been on a dynamic rope.
But I’m always on an atc or figure 8
That's why we use a asapsorber with static rope with rope access
i was once route building, on a dynamic rope, i knotted the rope at the top to reduce the stretch when building, now on the last 3 meters i was working and some test climbing and i had maybe 1m-1.5m slack on the last 2m from the anchor, yep that was not a pleasure
What about Samson Hawkeye 1/2 rope
Convert Hz to time, than all your references are in the same unit. Than its just a matter of which one is bigger/smaller to why it works.
Would be interesting to see the forces generated by multiple trad gear failures during a fall
That grigri to bolt is certainly “conservative”. I’d love to see how much lower the peak forces would be with a squishy human belayer and harness anchoring the grigri. Not that it would make it ok to whip on static line, but I suspect peak loads would be (statistically) significantly lower.
57 seconds in and I'm laughing my ass off. Love the skit you did with yourself. I just wanted to "like" that. okay I'll continue watching now. Byeee
the thing about force over time
best way I found to explain it is this
if you stop in a car you stop over time
if you run into a brick wall you stop quickly
have a great day :)
You could save yourself a lot of time with formulas in excel, count max etc.
For a long fall aerodynamic drag becomes a factor. For a very long fall "terminal" velocity, the speed at which aerodynamic drag equals weight, enters the equation. If you have enough elastic rope, at the same end as the weight, to handle that energy you should be good.
Thanks for your great videos. I'm interested in Numbers when children fall into a robe lead-climbing. Because of the weight, the robe will not stretch as much, and do the falls have a higher fall factor than?
to my knowledge, fall factor is not dependent on anything but height and rope length. but the force could be higher, would be interesting to see.
@@spud_67 Yep, and to add: less weight = less force. It will be plenty soft.
For a given rope, less weight means less force, but not proportionally less, so a lighter person will experiance a faster deceleration (more G's).
wondering if somebody made a harness that has built in a small rope spool and friction joint to act as a „fall airbag“. Whenever the force exceeds a limit, it would pay out from the spool. Matched with the climbers weight, it limits the g-force (until the spool runs out). 2-3m of g-limited fall might get you all over the high g peak and change back broken to it was a bit uncomfortable…
Combined with a spring returned one way clutch, it would auto reset after a fall and no more tension on the rope, so that a climber can continue their way but still have the safety of the airbag for subsecent falls.
Did you bring up climbing top rope with semi static? in your ice climbing video they using semi static for top rope, that should be safe as long you are under tension
Top roping with semi-static is totally fine. Obviously you don’t want a bunch of slack but that’s a good belay helps with that
I've seen a new micro wire gate carabiner rated at 8kn on Amazon.
I ordered a few for hammock / tarp stuff.
Curious what they really break at.
So break 'em
@Username
I do not possess the necessary equipment to perform such a test.
@@swartzautoman2 Sounds like a good project 👍
I took a bit of a "whip" on a static rope. Wasn't even uncomfortable. However I didn't fall straight down. I was mostly a swing.
Going from pounds to kN makes me sweat and breaks my brain. Any chance of showing mass in non freedom units?
"non freedom units" :) But just divide by 4.5
A falling climber on a static rope should get a pretty bad amount of g-force, from the sudden stop. But is it enough to main or kill? can you check G ratings?
Depends on the fall - might even be enough to snap the person in half.
Is there a way to tell at home if you have static or dynamic rope?
At what point does Kn translate to serious injury? Presuming the fall goes "well", i.e. no bumps into rocks or anything.
If it still has its rope end tags it should say there. If not then does it stretch when you hang on it such as in a repell?
Many dynamic ropes are made so they do not stretch too much with rappel loads. However, if you bounce up and down, you could comparatively tell the difference. If you happen to have a static rope and you bounce test it, you will feel a sudden jerky stop, it will be the opposite of soft.
this generates a lot of questions about the differences between dynamic rope cows tails and sling/cord made personal anchor systems. does it really make a difference when they are as short as the are? plus you are tying knots on the rope and reducing its strength while there are other systems that do't require knots. I've used both on work, but I've never fallen so can't say 😅
Friendly reminder: always work with a backup fall-arrest system that dissipates the force. Don't get yourselves killed at work, that's too sad. at least do it on the mountains🤙🏻
6:43 Why the hell does it say "30 kN" on the hanger if it bends / breaks at 8 ??
So. Best option would be a free belayer. To allow them to shoot straight up.
this felt like a step up in quality for the video... but I cannot put my finger on it
Anyone who's played Fleeing the Complex from the Henry Stickmen games knows what might happen
Was in a class and the instructors where preaching how important dressing knots is. Do you think you could test dressed vs undressed knots?
I feel like he's done this, to some degree, on figure 8 knots at least. But would love to see more knots tested for this.
I think the channel 'hard is easy' did some tests along those lines. If I remember correctly.
It shouldn't matter too much how much time it takes for the force to be applied. What would matter is how long the impulse needs to be applied.
The point of a dynamic rope is that it stretches to allow you to keep on falling applying a smaller force to slow you down the same amount but over a longer time.