Are drones really any threat to aircraft when we consider the weights of common birds?

[Big Bro]

Food for thought here, birds don't ignite when their outer casing is breached like a lithium battery. How would you like to play hot potato with a flaming battery that entered your cockpit? Or worse yet, one that hit the leading edge and made it's way to your fuel tank?

 

[snowghost]

Food for thought here, birds don't ignite when their outer casing is breached like a lithium battery. How would you like to play hot potato with a flaming battery that entered your cockpit? Or worse yet, one that hit the leading edge and made it's way to your fuel tank?

Good point. Ask the alligator about that.

 

[Mantrain]

Re

@Mantrain did you watch the video linked in this post:

Are drones really any threat to aircraft when we consider the weights of common birds?

I was wondering about this. I fly a few different drones, from the Mini 2 to the Mavic 3. As drone pilots we need to be so cautious regrading manned aircraft which share airspace. My largest drone, the Mavic 3, certainly cannot be discounted as an object that given some rare circumstances...

mavicpilots.com

yes that helps clarify. The video clearly shows the potential for disaster.

On the other hand I wonder then if future drone designs might be made to ameliorate impacts.

Now about birds: outside of evolution designing a bird to be aerodynamic, I think they are animal bodies like any other mammal (though they aren't mammals) they are avians . A 1.2 Lbs Crow is just that -- a 1.2Lb body.

So I think that maybe the impact of DJI drones and a large crow and or hawk would not be dissimilar. Whether they are or are not, drones could be a big problem like in the video. Science is about testing and until someone shoots a bird though a canon at a plane to see what would happen in the same way we have done drones then all we can do is hypothesize. I know what happens when a phantom hits a plane (in a laboratory setting). But I am not sure what would happen with a crow or a hawk. Another poster (pilot) indicated birds a problems too (and therefore would have been since 1903.)

Now of course the fact that Phantom, propelled to an airplane in a lab causes damage is room for pause. It is why we have drone regs.

I m wondering if some soft fabric like the Phantom wetsuit might do something to mitigate potential impacts.


Ok so as drone enthusiasts we must realize each time on takeoff the potential for having a really bad day given irresponsible behavior.

 

[AZDave]

So I think that maybe the impact of DJI drones and a large crow and or hawk would not be dissimilar.

Garbage. If I throw a 5 ounce rock at your head it's going to hurt a lot more and do a lot more damage than if I were to throw a 5 ounce balled up rag at you. Which do you think is more likely to break a window?

How people don't understand the difference is beyond me.

 

[MS Coast]

Science is about testing and until someone shoots a bird though a canon at a plane to see what would happen in the same way we have done drones then all we can do is hypothesize.

Do a search for flight impact simulator or chicken cannon. That sort of testing to evaluate the damage from bird strikes has been going on for decades. Here's a recent article about it.

The cannons keeping airplanes safe, one chicken at a time

At a Canadian research facility, tests are carried out on aircraft parts to ensure they can withstand the impact of birds and drones. The ammunition? Bird carcasses, which are shot at the plane through a cannon.

www.cnn.com

Sofa pillow or can of beans? Same weight but very different potential for impact damage to the forehead. See post #28.

 

[MS Coast]

Some of the local species can be in the twenty pound range (turkey vultures) which are impressive then they get hit.

Not trying to be argumentative, just sticking to the facts. A 5-pound Turkey Vulture would be an unusually large one.

Turkey Vulture Identification, All About Birds, Cornell Lab of Ornithology

They're still a potential problem. (But not a bad as a 5-pound canned ham.) (Humor. But true.)

 

[Mantrain]

I am sure this has been discussed but I a only more recently into drones. How much damage could less than 250 gram drone really do compared or not compared to a bird?

 

[sar104]

ok so the conclusion of this is that a drone of relative weight is more of a physical threat than a bird of similar weight. I am not the expert so if that is what the experts say I am not going to argue that.

Except now you are going to argue...

I will say though that DJI drones do appear to be made as sparing as possible and not particularly robust. For example my Mini 2 is very dainty and almost featherlike [until I insert the battery.]

Do you fly often without the battery?

and one more thing, given Newtons 3rd law if DJI drone of similar weight is more of a threat than a bird of similar weight the only way tht could be is if the latter's weight is distributed through more area.

Just stop - you have no idea what you are talking about.

Firstly, this has nothing to do with Newton's 3rd law, which doesn't have anything to do with weight, area or pressure. It is related to the differential form of Newton's 2nd law, in that the force exerted during impact is equal to the rate of change of momentum during the impact. And the rate of change of momentum is a function of the duration of the impact, which itself is a function of the rigidity and strength of the materials involved.

Soft materials, a category that includes birds, are quite compressible and so the impact lasts longer, the rate of change of momentum is lower, and the impact forces are lower. Rigid materials, including various drone components, are not very compressible; the impact duration is short, the rate of change of momentum is much larger, and the impact forces are much higher.

 

[bcfd29]

Thank you,

So according to your expert knowledge birds are a safety issue for manned aircraft and contrary to what others have posted birds are not merely vacuous bags of fluid that splat into nothingness on impact.

Appreciate your feedback.


One thing though,

by bird strike, are you referring many birds at once? Or are the issues from single offenders as well?

a single contact with just ONE bird causes these damages.

 

[Maviac]

Food for thought here, birds don't ignite when their outer casing is breached like a lithium battery. How would you like to play hot potato with a flaming battery that entered your cockpit? Or worse yet, one that hit the leading edge and made it's way to your fuel tank?

I'm not so sure: Birds aren't real.

 

[AZDave]

Except now you are going to argue...

Do you fly often without the battery?

Just stop - you have no idea what you are talking about.

Firstly, this has nothing to do with Newton's 3rd law, which doesn't have anything to do with weight, area or pressure. It is related to the differential form of Newton's 2nd law, in that the force exerted during impact is equal to the rate of change of momentum during the impact. And the rate of change of momentum is a function of the duration of the impact, which itself is a function of the rigidity and strength of the materials involved.

Soft materials, a category that includes birds, are quite compressible and so the impact lasts longer, the rate of change of momentum is lower, and the impact forces are lower. Rigid materials, including various drone components, are not very compressible; the impact duration is short, the rate of change of momentum is much larger, and the impact forces are much higher.

Great comment, and you are exactly correct. Mantrain seems unlikely to be convinced by the physics of the situation, but most everyone else should be able to understand your spot on explanation.

 

[snowghost]

For those who "think" a drone wouldn't do any more damage than a bird of equal weight (SIGH) here's what a bird CAN do to a GA windshield:

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If you were flying that airplane or someone you loved was on board how would you feel about a drone coming crashing through the windshield . . . ????

Knocked his glasses off.

 

[Mantrain]

Great comment, and you are exactly correct. Mantrain seems unlikely to be convinced by the physics of the situation, but most everyone else should be able to understand your spot on explanation.

I agree with the physics I m not mechanical engineer nor an expert in a related field.

 

[Big Bro]

I'm not so sure: Birds aren't real.

Not sure we should go down this road, but it's most likely that none of this is real.

 

[EsaT]

A 1.2 Lbs Crow is just that -- a 1.2Lb body.

And what's the size/impact cross section of that crow?
Compare that to impact cross section of roughly same mass Air 2.
So even assuming same impact energy, drone would create clearly higher impact force per area/pressure.

And that crow is made mostly from squishy material with even some cushioning included.
So even if size wasn't bigger in direction of travel during impact, energy transfer would happen over longer time further decreasing impact pressure.

This actually works as good example how smaller total energy can be more destructive when energy is transferred almost instantly instead of over time:

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[Mantrain]

I did not mean to make so many people angry I was just hoping to understand better the comparison of birds as a threat to DJI drones. I am sorry for making so many people here angry.

 

[sar104]

I did not mean to make so many people angry I was just hoping to understand better the comparison of birds as a threat to DJI drones. I am sorry for making so many people here angry.

I don't think that you made anyone angry, although you probably frustrated a few people by continuing to misunderstand the entire topic and by appearing either not to read or not to understand the answers that you were given.

 

[DoomMeister]

I think we can consider this topic covered and explained as some posts are straying from the topic and there doesn’t seem to be any newer information over the last page of posts.

Thread closed!