r/interestingasfuck • u/Red_Lotus_Alchemist • 2d ago

/r/all A Chinese earthquake rescue team deployed drones to light up the night and aid search and rescue operations after the devastating 7.7 magnitude earthquake in Myanmar.

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u/boteco 2d ago

Drone with cables! Crazy simple idea,

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u/karateninjazombie 2d ago edited 1d ago

It's called a teather drone. The most common idea I've heard bandied about in drone circles is uses in event security.

I like the search and rescue lights idea. They could put thermal cameras somewhere or too for other types of s&r operations too.

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u/bnlf 2d ago

There are drones used by fire department connected to water as well to help put out fire on high buildings.

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u/mxforest 2d ago

My city uses them to clean high rise building.

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u/s1ugg0 2d ago edited 2d ago

Drones being used for putting water on a fire in a meaningful way is a LONG way off.

The first problem is weight. Water weighs 8.34 lbs per gallon. The smallest attack line we use is 1.75 inch hose line. A single section of 50 feet of a 1.75 attack line weighs 70lbs when charged with water. We often use many sections because 50 feet is a lot shorter than it sounds. Plus it would have to counter the recoil of the nozzle. There are helicopters that would struggle to do that.

The second problem is friction loss. The higher you go and the more hose you deploy the harder the pump has to work to maintain flow rate. Which can quickly over come even our massive pumps. It's why FDC connection points are mandidated in all multistory structures.

Now drones for observation and muling tools is a totally different matter. And that has already started. Even my vollie department in NJ is testing observation drones with a thermal camera.

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u/2xtc 2d ago

How do these things exist and work then?

https://youtu.be/11enxgxsanU?si=lZZtSfdXmf5wssKi

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u/s1ugg0 2d ago edited 2d ago

Please notice I said "putting water on a fire in a meaningful way". These drones are for such specific circumstances they are practically useless.

In the wildland fires they do not have the range or capacity to do suppression in any meaningful capacity. By the sheer volume of miles it would have to cover it could never respond to the scene fast enough to be useful. The fire will have grown too big for it's small reservoir of suppressant to work.

Take note that wildland firefighters all over the world aren't asking for suppression drones. They're begging for things like the Canadair CL-415. Which can put more suppressant on a fire faster than anything else.

In structures fire it only works in these sterile commercial tests. Two things to know about structure fires. With typical, normal class A combustibles the fire can double in size in as little as 60 seconds. That's not an exaggeration. Here is an actual demonstration of what I am describing. In this video from spark to flashover is 3 minutes. From room temperature to over 1000 degrees in 3 minutes. A flashover will burn or kill anything or anyone virtually instantly. Even firefighters in full PPE. Sadly it has.

Now ask yourself do you think that any of these drones could make it to a fire faster than 3 minutes or have enough suppression do anything meaningful against an +1000 degree fire? Well I don't.

Also the weather. We have to respond no matter what. There are extremely few instances where FDs stop operating. There is no such thing as a rain delay. It doesn't matter if there is 6 feet of snow and it's -50 degrees. Or the wind gusting. Or when it's 100 degrees and we start passing out. When I did my window bailout training I did it during a snow storm. The instructor blindfolded me and then ordered me to escape out of a five story window in a snow storm. This not me bragging. Every firefighter has a story like this. It wasn't even that dangerous to tell you the truth. The point is how effective do you think these drones will be in bad weather? A time when our services are most requested.

If you would like to see a real fire suppression drone in action please allow me to introduce you to Paris FD's "Colossus" This is the real deal and gets used all the time. And as you can see it's a firefighting tank. Because that's what it takes to make it to the seat of a structure fire sometimes.

By the way quick shoutout to Paris Fire Brigade. They're excellent firefighters. They're actually a department of the French Army and were formed by order of Emperor Napoleon in 1810. All of their firefighters are technically sappers. Their motto is "Sauver ou périr" or in English "Save or Die"

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u/FloridianfromAlabama 1d ago

They’re fucking massive.

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u/Craspnar 1d ago

Isn't that video AI generated?

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u/Far_Tap_488 1d ago

Because ypure average alcoholic pisses out more fluids in an hour than these drones can put on a fire.

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u/GIC68 1d ago

This is probably not water, it's foam or CO2 extinguishers. And these only work on a rathermlimited distance and limited size of fires.

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u/Wood-Kern 1d ago

This might be ridiculous, but if the drone is shooting water downwards, does that not help quite a lot with the lift? Obviously the drone would need to be entirely designed around that concept. Or at a certain point the effect just doesn't matter enough, as as you get away from the ground the weight of the hose keeps getting heavier but the trust from the water stays the same. Plus you would be extremely limited in the angle that you eject the water.

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u/Ciff_ 2d ago

It is very heavily used in ukraine rn. You can prevent jamming. They use several hundred meters of cable mainly for control.

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u/oddly-even321 2d ago

The drones currently in Ukraine have cables length of about 10-20 km.

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u/S_J_E 2d ago

Also they're only being used for data transfer, whilst the one in OPs video I assume is just for power

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u/Ciff_ 2d ago

Yeah I think so, they also burn though them fast, flight tile is likely not an issue

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u/GiantManatee 2d ago

Those cables are thin too. You'd need superconductor wire (the holy grail of materials engineering) to power a drone through cable 10 km away.

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u/oddly-even321 2d ago

Those cables are fiber optical, so they can only used for data and no meaningful power even with a short cable.

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u/GiantManatee 2d ago

I'd love to see the kind of laser needed to power a drone over optical cable :D

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u/oddly-even321 2d ago

Big scary laser, protect the remaining eye.

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u/Dude-Hiht875 1d ago

small pulse laser of the Battletech universe

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u/Far_Tap_488 1d ago

Only for comms. Not power.

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u/Unkinked_Garden 1d ago

I heard kilometres of cable. It was on the interment so….

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u/anr4jc 2d ago

My wife works for a company that has a proprietary technology that uses drone to relay high definition audio/video signal from firefighters to the ground. They use this to remote control drones that can go where humans can't and send a real-time signal to a remote operator. The tech is pretty neat.

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u/FixedLoad 2d ago

I would like to replace a street light with a tethered drone. It could land during the day and take off at dusk. Replace those crazy tall lights on highway interchanges.

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u/ludololl 2d ago

They're loud, opportunity for theft, likely dangerous to birds, lots more maintenance, unable to function in storms or high wind.

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u/FixedLoad 2d ago

And that's plenty of reasons why I shouldn't. Impulse idea solved!

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u/Generatoromeganebula 2d ago

Pretty much they are pretty inefficient for this purpose.

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u/Busy-Pudding-5169 2d ago

They can most definitely be water proof, and DJI drones can definitely withstand strong winds. You’re not informed 

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u/GeForce-meow 2d ago

In Ukraine armies are using tethered drones ( teather is used for signal transfer ) so they are not affected by signal jammers.

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u/karateninjazombie 2d ago

The drones being used in Ukraine are slightly different to this one. This one has no battery on the flying part and is powered by the cable as well as probably controlled by it. (Depending on how it's been built)

The ones being used in Ukraine have a cable or fibre optic line for control signal only and have a battery on board. They also unspool a from a roll on the drone so they can travel without getting snagged. That way they get around the whole jamming issue.

I believe the it's fibre optic line from what I've been able to find out about them.

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u/ASubsentientCrow 2d ago

They could be good for anything that have higher power draw. Cameras, lights, radio relays. And the loiter time would essentially be as long as the generator holds out.

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u/karateninjazombie 1d ago

Yes. Well done captain obvious.

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u/Mazon_Del 1d ago

My old college had a prototype about 10 years ago for an interesting concept with a tethered drone.

The full sized one (never built) was to be quite massive, as the idea was the thing used electricity from the cable to fly its way up tens of thousands of feet to the operating altitude, then it would switch to "kite mode" and instead of putting electricity into the props to gain altitude, the winds at those speeds would be sufficient to keep the drone lofted and push on the props to generate electricity which gets sent back down the cable. So basically a flying wind generator.

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u/karateninjazombie 1d ago

Interesting concept. I'd hazard that the weight of the cable and the cable losses at that kind of distance make it only give marginal returns though.

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u/Mazon_Del 1d ago

I remember they had some estimates for that kinda stuff, but the project was so long ago and I'd only passingly read the document, so I won't even try and guess their estimates hah!

If I remember right (and I probably am not), the prototype methodology was to get the thing up to its test altitude (only a thousand feet or so) and then do the helicopter equivalent of autorotate on the way down to establish a baseline power. Repeat it several times with various wind measurements. With higher winds they should generate more on the way down.

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u/Dude-Hiht875 1d ago

A very optimistic concept. Because no matter how ridiculously big the drone is constructed, a wind mill will be greatly bigger.

And because the economy of scale is the thing.

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u/Mazon_Del 1d ago

As I recall the idea was that the drone's advantage lay in the higher windspeeds at higher altitudes. So it has a smaller surface area relative to a fixed structure windmill, but it can access windspeeds far higher.

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u/Dude-Hiht875 1d ago

Do you know one of the simplest, obvious and common rule of mechanics/engineering?

The faster speeds, the faster accelerations/decelerations means the wear is greatly quicker. And it has a geometric progression. Be it an internal combustion engine or say an automatic small arm.

Specifically for drone, it means its small blades will rotate with such great speeds that in theory the tangential speed might closely approach the speed of sound. That is completely undesirable.

Civilian engineering is about lasting long. This drone will need times more maintenance than a stationary wind turbine.

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u/Mazon_Del 1d ago

Civilian engineering is about lasting long. This drone will need times more maintenance than a stationary wind turbine.

This is likely one of the many reasons the prototype was never followed up on.

But don't forget, speed isn't the only thing that increases wear and tear. Increased force on your bearings does too. Bigger windmills don't just get away with "build a bigger bearing", that has its own design challenges.

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u/Dude-Hiht875 1d ago

Yet bigger bearing that feels a small angular speed lasts longer than bearings ought to work on higher speeds. The answer is heat. Which again is the function of speeds : )

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u/Inner_Extent2375 1d ago

How much louder do these make emergency scenes?

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u/karateninjazombie 1d ago

Not overly. You'll hear the buzz of the drone of its low enough and the generator. But very quiet generators exist and it sounds like they are using one such item.

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u/ThatGamerMoshpit 1d ago

It’s great until one gives out unexpectedly and kills someone

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u/karateninjazombie 1d ago

A regular drone can do exactly the same thing and we still use them.

So 🤷‍♂️

Teather drones can have a much much longer loiter time compared to battery powered drones.