Japanese Fire-Fighting Dragon Rides Water Jets

If you are building a robot to fight fires, why not use the water that you are fighting fires with to propel your robot? That seems to be the idea behind the Dragon Fire Fighting robot built by [Professor Satoshi Tadokoro], and his team at Tadohoku University. Their dragon robot is raised by the same directed jets of water that are used to stop the fire.

The three-meter robot also uses these jets of water to steer, moving the dragon’s head by firing water jets at angles. I’m not sure how practical it really is, though: the jets that the robot uses to steer could do as much damage as the fire itself if it wasn’t used carefully. The idea is to attach it to the end of a ladder or crane used by firefighters, so it can explore a building on fire without anyone having to step inside.

The robot was built as part of the Tough Robotics Challenge, a program that is looking to build robots that can help in disasters. Japan is one of the most disaster-prone places on the planet, thanks to earthquakes, nuclear meltdowns, and Godzilla attacks, so the program is looking to build robots that can help out. Some of the concepts they are looking at include cyborg animals, a listening drone that can help find survivors after a disaster using a sensitive microphone array and a serpentine robot that can map pipes and underground structures.

[Via TechXplore and Qes]


47 thoughts on “Japanese Fire-Fighting Dragon Rides Water Jets

    1. Well, it is similar to rocketry: the thrust you get is proportional to the weight of the stuff expelled times the velocity. So you can surely replace every liter of water by about 1 cubic meter of air/nitrogen…

    1. I don’t think it is hand steered, you can see the jet direction changing but it is a pretty crap video as far as gleaning any info about how it works goes.

      I think it’s a good idea in prototype form and that is the starting point for most things.

    2. Yes, but is cereal a soup? Are pop tarts sandwiches? The definition of Robot can be so generalized to mean “a programmable device”, is an alarm clock a robot? Is a quadcopter not a robot because it has an operator, even though things like staying upright are handled automatically? Aren’t we then splitting hairs about at what proportion of semi-autonomy dictates “robot”? Some things to think about, but more linguistic questions than technical.

      More to the point though, I think I can see green lights on the head and the mid section, so I think those parts are at least modulating the water streams to do some kind of position stabilizing (gyros/accelerometers) even if it is manually guided. Also, the cart just moved it closer to the fire, when it was kind of over it, the cart stayed stationary but the head moved to actually hit the fire.

  1. “I’m not sure how practical it really is, though: the jets that the robot uses to steer could do as much damage as the fire itself if it wasn’t used carefully.”

    And the existing hoses and nozzles can’t? If anything, the jets on that look pretty underpowered compared to a standard 4″ line.

      1. Close, but not quite. The objective of firefighting is to minimize loss of life and property damage. This includes the property that’s on fire. If you have a fire confined to a bedroom, the objective is to put out that fire without causing undue damage to the rest of the house, for example. On encountering a house fully involved, which I think is what you mean, the objective is to minimize damage to the neighboring houses, including damage caused by streams of high pressure water.

  2. Newton’s 3rd law: in order for it to just stay in place once it’s in position, it has to direct as much water AWAY from the fire as it does toward it. I guess that’s probably okay if it’s inside a burning building, but yeah, collateral damage.

    1. Except that that’s not what newton’s Law says. Even in the video, it doesn’t do this, it fires downwards in the fire, using no more water than it was to stay flying.

      1. Dan: Except, yes, that IS what Newton’s 3rd law says: for every action there is an equal and opposite reaction. Combined with the 1st law, conservation of momentum, shoot water forward, the nozzle moves backward. In order to not accelerate, you have to balance the forces, and unless the steering water pressure is somehow higher than the firefighting water pressure, that means balancing the mass of water being moved. Yes, they’re aiming downward at the fire, but not directly so, the steering water also has to aim the same angle downward but in the opposite direction downward. The downward component balances the weight of the hose and water. Which brings up another problem: the higher the nozzle goes, the heavier the hose and water column get, and the more water flow you need, just to keep the hose in position. The flow of water is dictated by the height you need, so you can’t vary the flow rate to suit the fire.

        1. That’s not the best synopsis of Newton’s third law: it really should be that there are equal and opposing forces in every interaction. Just because you’re pushing water forward toward the fire does not mean that the entire apparatus moves away from the fire. Otherwise, how would any fire truck work at all without hurling itself across the street on top of innocent but stupidly-curious bystanders?

          1. Seriously? “Just because you’re pushing water forward toward the fire does not mean that the entire apparatus moves away from the fire.” ??? Have you ever seen firefighters on a 4″ line? It takes two or three of them to withstand the force. Fire trucks don’t go careening across the street because they have TIRES that are friction coupled to PAVEMENT that can take a great deal of force before slipping. Because, you know, that’s how vehicles work. The “dragon” described here is a free-floating body, so yes, just because you’re pushing water forward DOES mean that the hose is pushed backward. Look at the picture above, and you’ll see that there is just as much water going away from the fire as there is towards it.

          2. I have seen firefighters on those lines. I’ve held those lines myself (my cousin was a firefighter). You’re right. But what’s not right is saying that you have to direct as much toward as you do away–if it were in free space, sure. But it’s not–it’s here, one the ground, with real-world physics like tension in the line working against that force.

            The point I was trying to make is that the cliche “equal and opposite reaction” has a connotation that the whole thing will move away. Sure. At least, that is, until *all the other forces in the system* counteract that. The friction in the tires is exactly what I was referring to. I was not suggesting that there are other considerations to how feasible this system is, merely pointing out that it doesn’t help to neglect all the other things that are present to hold the system in place for its task–the mass and friction of the whole pump frame to the ground, the tension in the hose and linkage system, the guy physically holding the system in place… Did you watch the movie? Obviously the thing “works”. Whether it’s valuable or not… that’s another discussion.

          3. Okay, I’ll say it again, then. I was wrong. I was taught wrong, and I believed it. It will probably help to reinforce the truth if lots and lots of people explain to me how wrong I was. Thank you.

        2. Your logic applies to the entire firehose+firetruck system, but doesn’t work when applied to the nozzle alone. The nozzle has water going in at one end and out the other; as long as it doesn’t restrict the flow, there’s no net force on it (neglecting gravity). And if it does restrict the flow at all, the resulting force pushes it *forward* (towards the fire).

          You were almost right; large forces will be generated that will have to be compensated for, but not necessarily at the nozzle. Rather, any bend in the pipe will create a force going “out” of the bend that will have to be dealt with. It seems unlikely that this system will tolerate any bend sharper than a few degrees without external help or massive loss of water. However, there’s still hope; presumably the hose can “brace” itself against walls/corners/doorways/whatever.

          1. Which would make sense if the firehose+firetruck system was a rigid body. Because the hose is flexible, the nozzle has to be treated as a separate body. Yes, there is SOME force countered by the hose, but very little compared to the force applied to whatever is holding the nozzle. Do you seriously think that firefighters don’t have to push forward on their hoses? Do you believe that the force gets transmitted all the way back through the hose to the truck? Try this with a garden hose. Does the pipe the hose is connected to take the force, or does the guy holding the nozzle?

          2. Well, then I’m wrong. It’s not the first time I’ve learned I was taught nonsense. Not only that, but it tends to explain why a (curved) hose with restricted flow at the nozzle behaves chaotically, which is something I’ve never understood.

    2. I can see that as more of a targeting problem. I.e. get the spray head to a spot where all the sprays help out. Say, the center of the blaze? I bet this ends up with an omni-directional misting head most of the time.

    1. I was going to comment on the gallons of water sprayed in areas away from the fire… but as I think about it, even if the fire being put out was that localized, there is benefit in drenching everything around it so as to inhibit the spread of the fire. So perhaps not as wasteful as I was originally thinking.

      1. Doesn’t matter anyway, Japan has enough water to waste a bit extra putting out fires. It’s not the middle of a desert.

        If a fire is small and localised, they probably won’t be sending a team up with a ladder. This is surely for bigger fires.

  3. GImmick.
    Why would you even bother with a fire so low to the ground? You could deliver a much higher volume with hand held at this height and, when you’re looking at 2nd story or higher the amount of pressure & water in order to lift the hose (with the water inside) to that height I can’t see this being practical.

  4. There is probably less water being wasted here than blindly firing a hose through a smoke filled room from a distance.

    That said … you could also use the water pressure to turn copter blades, and have all the water continue on to the target.

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