Kirigami-Inspired Parachute Falls on Target

The tested it with a standard size waterbottle, so you know it works fine for 0.8 kg paloads.

Depending on the use case, a hot-air balloon sized parachute to safely drop a person might be perfectly acceptable.

It looks like adding flexible ailerons or whatever they'd be called could give a big advantage in precision landing, with slower forward/sideways speeds but much better control.

Making it modular, with interlocking but separate parts, might make great sense for repairability and safety for skydiving? From the little I know of the sport, things tend to fail catastrophically, going from perfect condition to total disaster without a whole lot of graduated steps in between. I also wonder if there's some utility in paramotoring - multiple kirigami stabilizers, maybe, with a central parafoil, or one big kirigami rig with the fan blowing straight up its skirt?

This is awesome research. Paper drone-delivery parachutes are definitely a use case, but maybe some of the more dangerous flying sports could be made much safer, as well.

edit: Apparently no, 100 meter radius kirigami chute would be needed for a single person parachute, not exactly practical. Apparently it's just really, really good at ensuring things drop straight down with a lot of drag.

Spider ballooning is an interesting phenomena. I also assumed that the spider is just falling a bit slower than the air is rising, due to convection. However some people think there is also a strong electrostatic component to spider ballooning. I'm not sure how that works once the spider is well clear of the ground though.

I've worked on mission planning software for parachute systems and the precision we can achieve is already extremely high. Given how poorly this seems to scale, the only use case that makes any sense to me would be something like sensor drop, which are the only payloads small enough for these chutes. Or potentially for drogues on multi-stage systems, but I'm not sure they'd even be useful there because usually a fast descent is part of the appeal of a drogued payload, and not just to reduce time exposed to wind drift (e.g., to reduce time it is vulnerable to enemy fire).

  >Baby spiders use "ballooning" -- a single thread -- to fall so slowly that they can travel far in thermal updrafts.

It's even cooler. Spiders probably also exploit the Earth's natural electrostatic gradient (100 volts per meter!) to "ride" on electrostatic repulsion. This would even give up and down control, simply by changing the length of silk.

https://www.youtube.com/watch?v=Ja4oMFOoK50

https://www.feynmanlectures.caltech.edu/II_09.html

Does the (stainless steel?) vacuum bottle, used in their demo, not have significant mass?

https://www.coopoly.ca/p-545851-bouteille-noire-thermos-510m...

Note also the extra weight attached by the researchers to its bottom

(This is not yet taking into account the data-based scaling formulae presented in the paper)

>> does not scale linearly

It looks like it depends on the stiffness of the material (paper), so scaling it up to human (or bigger) sized will come with "interesting" challenges :(

Looking at the video, it seems that even the bottle lands quite fast.

https://news.ycombinator.com/item?id=45495711 - I think you meant to comment on this one.

I had to wonder if Nature (the Mother, not the journal) had first created anything similar, because she always does.

One answer is a dandelion seed. Not exactly the same, but a dandelion seed is about 85%+ "porous" - the pores here being the space between the spindles, not actual holes per se. And it turns out that high porosity is critical to stabilizing the wake turbulence not unlike what is described in the Nature video. https://sites.nd.edu/biomechanics-in-the-wild/2021/06/01/inn...

A learning that kirigami parachute researches might apply: The dandelion pappus is less porous near the center and becomes more porous toward the outer edge. A lower porosity near the central hub can increase shear flow, helping to detach and strengthen the vortex

Furthermore, spiders which have been known to "balloon" on the wind even across entire oceans use multiple strands of silk which are negatively charged to repel each other, thus forming some of the same gaps that are seen in a dandelion pappus, with similar aerodynamic benefits. https://journals.aps.org/pre/abstract/10.1103/PhysRevE.105.0...

  > As well as kirigami, the team drew inspiration from nature. Instead of relying on a gliding angle, many wind-dispersed seeds are equipped with structures that stabilize the airflow around them: including the feathery bristles of dandelion seeds, which create a stabilized vortex in their wake.

Is that really Nature's channel? It sucks that I have to ask, but I just ran across that video (and channel) on the weekend. I have a new policy where I don't trust videos to not be AI slop when they don't have a real, on screen presenter. This one didn't, but it also didn't really feel like AI slop, but it could have been stolen content since that is very common nowadays because it goes unpunished.

your PhD probably gives you the wherewithal to do the cool things now or after a few years of work ...

Applied topology and fluid dynamics + origami? Pretty sure there’s no program for this so you can just show up.

Also I bet they really need people who can help with the simulations. If you email the authors you can probably get added to the team.

I too love this. It’s that intersection of devilishly hard and almost useless unless you squint then it’s sci-fi magic tech. There are quite a few cases where you want the parachute to drop straight down.

It comes as a flat disc. For some applications that might be more convenient packaging than traditional parachutes.

I thought the same at first, but actually - you don't want your bombs to fall slowly. Supply drops are another matter. These don't kill people directly at least.

>I could't help but roll my eyes at this textbook example of describing new technology as being "useful for humanitarian or search & rescue work", instead of the much more obvious usefulness in military applications.

I've seen this so many times now. Is there a established Internet meme for it yet?

This is for Amazon deliveries. The whole thing is written for that, the material is the same as their packaging even.

Bombs go down fast, specially from drones, there's no advantage in slowing them down.

Both can be simultaneously true.

Dropping supplies to isolated or behind-the-lines forces is a very real logistical issue. While some of those supplies might be munitions, rations and medical supplies are a significant part of the need.

I know, it doesn't make you feel any friendlier to the issue, but tech has multiple applications. Chainsaws were invented to increase survivability of mothers in difficult births.

Why would you want to make a bomblet fall more slowly (allowing the intended targets to escape)? They already have fins to maintain their approximate direction.

That war frequently goes very low tech (kind of COTS :) - plastic bottle as stabilizers

https://youtu.be/dcsf5yuEHDY?t=69

https://forum.cartridgecollectors.org/t/drone-dropped-anti-t...

On the second pipe you can also see small fan which probably arms the side attached detonator.

I always assumed that drone delivery was just a publicity stunt (in urban areas anyway). I am hoping that it stays that way. I am really not convinced that a sky full of buzzing drones delivering people's toothpaste and takeaways is a great idea.

Biopolymer or paper, hopefully.

My grandma wouldn't have been happy if my father dumped the bucket from the well near the kitchen sink.

Nothing much has changed about precision in delivery of goods.

Rest assured. This will only be used for cluster bombs.

Six pack rings were the first thing I thought of when I saw the picture. The article says they made the parachutes out of paper and cardboard too, but if history is any guide they'll end up making them from plastic. "What if it rains!?"

Dropping bombs straight down seems like a solved problem. The difficult part here is dropping something slowly.

Relief packages, cheaply dispersed over a multi-block area, would make it more difficult for invading forces to massacre civilians at drop sites.

I can think of one place that would have IMMEDIATE utility.

Hey! As a simulated NPC, I don't appreciate being called out like that.

Baader-Meinhof in action :)

That's literally drone delivery.

My uneducated guess is that they would interfere with each other, and only whatever portion of the top ones that fits the profile of a single, larger chute would give you any extra lift. To the point that you are better just making a single one the size you need.

I've read that you have to move them several miles if you don't want them to return. Back when I had a mouse problem, I would take them to a field behind my gym.

And at first I thought, "Why would anyone need parachutes for pennies? Hell, we don't need those coins in the first place!"