Phantom 3 fell from the sky and crushed the roof of a moving car

[Dudez]

Most convertibles also have pop up roll bars if a crash or rollover is sensed.

I meant to protect me from a falling drone

 

[EyeWingsuit]

I am not Sherlock Hokmes. Hahaha. But physics and aerodynamic tell me with battery at the bottom and those prop on top. The chance of a quad falling down from the sky upside down is ar........unlikely?!


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You're right; you're not. On July 4, 1998, a skydiving camera operator lost a battery from his Sony VX1000. It's a very small battery. It went through the roof of a small car (I do not recall the make/model) but it caused the driver to turn the car towards, and impact a steel utility pole.

In 2013, a skydiver lost his camera and lens during a hard opening. The lens separated from the camera body and penetrated a home's roof, shattering on a granite countertop.
In 2014, Santa Barbara, CA, a skydiver was flying a flat with a 4lb weight on the flag's selvage edge. It fell off, penetrated a corrugated steel roof on a baseball field.

The phantom has plenty of weight to damage a car roof (as do most camera-capable UAV. As far as angle of impact...
I tested several weight and angle configurations and without significant input, could never get this laptop to fall to the ground with any consistent angle. Speed built up and it spun, flipped, and sunfished. Sometimes it landed on its back, sometimes on its front, sometimes on its side, and once on a corner.
There is no reason to disbelieve this story.

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[Erised]

There is no way that quad made that damage. Two big dents made by two feet jumping on the roof seems more like it!

 

[EyeWingsuit]

How does a less than a two foot quad weighing less than 2 lbs hitting a four foot wide roof with one impact create that kind of damage. It wasn't even at terminal velocity. I see absolutely nothing that says a quad hit it no matter how it fell. The roof is curved up which gives it strength so it's stronger than a flat roof section. And yes, I have worked with metal structures and welding for over 40 years so I do have a clue.

What is the terminal velocity of a Phantom? Querious minds want to know. Seriously. <hint> it isn't what you learnt in gradeschool.

 

[EyeWingsuit]

No one is expert in accidents. So some people just believe in me and I just believe in that and saw that the girl told me.

The bad is to discredit. No one is taking advantage of this story.

I am a professional in the field, I long that the profession of aerial filming with drones is something serious and safe. So I'm posting the story to alert DJI drones that are in the hands of irresponsible and a serious accident will happen sooner or later.

Actually, there are professionals in the accident reconstruction world. In the sport of skydiving, I happen to be one of them.

 

[Air Ontario]

I have seen a few vandalism cases on automobile roofs and hoods and given the evidence of the photos it doesn't appear to be straight forward vandalism damage alone.

I do have some issues with what I see with the overall evidence but not enough to discredit a drone impact. There just isn't enough evidence to say 100% either way so I go with the combined photo evidence and testimony at this point.

 

[djphantom2015]

The damage sure looks exaggerated, unless in Brazil they build cars out of paper. If the velocity was 22 m/s like in the screenshot that is 80 km/h which makes sense. This means, for my knowledge, the an object of 1,3 Kg had an impact like putting a 52 kg weight. (80x (1,3 / 2)). So my conclusion is, don't buy any car in Brazil

 

[sar104]

The damage sure looks exaggerated, unless in Brazil they build cars out of paper. If the velocity was 22 m/s like in the screenshot that is 80 km/h which makes sense. This means, for my knowledge, the an object of 1,3 Kg had an impact like putting a 52 kg weight. (80x (1,3 / 2)). So my conclusion is, don't buy any car in Brazil

Why would the product of velocity (in km/hr) and mass (in kg) divided by 2 have any bearing on the equivalent force of the impact? It's not even remotely dimensionally correct. It's half the aircraft momentum in the bizarre unit system of kg.km.hr⁻¹. And force is the time-derivative of momentum, not momentum, anyway, so you have to know the duration of the impact even to estimate force.

The correct expression for the force F (in Newtons), which requires an assumption about the distance, s, over which an object of mass m (e.g. 1.5 kg) is decelerated from its initial velocity, v, of 22 m/s to 0 m/s, is given by the rate of change of momentum during the impact. With the approximation of constant deceleration, and eliminating time from the resulting equation, we get:

F = mv²/2s
​

With an assumption of s = 5 cm (0.05 m) this gives F = 7260 N, which is equivalent to 741 kg.f or 1630 lbs.

The duration of the impact will be 2s/v = 4.5 ms.

Note that the force is inversely linear with the stopping distance, so if we instead assumed a 10 cm distance (dent depth) the force would be half of that estimate.

 

[Ramphex]

Cars are made of sheet metal, anything will damage it.... another car's door, hail, rock, fist.

If you don't believe it, go ahead and give your smart phone with a good case a nice toss at your door and post the results

 

[Waylander]

Bird strike.. ECU or motor failure... apart from flying in an appropriate area, the pilot had no chance of saving the drone...
Waylander

 

[TheLightSpeedz]

I have seen a few vandalism cases on automobile roofs and hoods and given the evidence of the photos it doesn't appear to be straight forward vandalism damage alone.

I do have some issues with what I see with the overall evidence but not enough to discredit a drone impact. There just isn't enough evidence to say 100% either way so I go with the combined photo evidence and testimony at this point.

Why is everyone here so quick to judgement. I hate that about this site.

I think the more likely story is HE IS the owner of the Drone, and he was sharing his story without admitting fault on a forum like this?

Either way I think the pic with the drone on the roof and the battery burning is pretty easy proof. The only thing that makes me suspicious is the DJI GO app screen shots.


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[TheLightSpeedz]

Oh and by the way, I had a P3A actually do this... Just fall from the air! It came down with a loud THUD and out a dent in a rubberized roof! Scary. They are heavy when falling from that high of an altitude


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[Rocky Mountain Old Boy]

The correct expression for the force F (in Newtons), which requires an assumption about the distance, s, over which an object of mass m (e.g. 1.5 kg) is decelerated from its initial velocity, v, of 22 m/s to 0 m/s, is given by the rate of change of momentum during the impact. With the approximation of constant deceleration, and eliminating time from the resulting equation, we get:

F = mv²/2s
​

With an assumption of s = 5 cm (0.05 m) this gives F = 7260 N, which is equivalent to 741 kg.f or 1630 lbs.

The duration of the impact will be 2s/v = 4.5 ms.

Note that the force is inversely linear with the stopping distance, so if we instead assumed a 10 cm distance (dent depth) the force would be half of that estimate.

Got to the party a bit late, but Sar104 has summed it nicely though area affected would be a factor as well (we - mine engineers - use similar calcs in mine blasting).

Long story short, there is every reason to believe that very significant damage would result from one of our birds falling from 100m - regardless if the car owner did a dance to enhance the damage for purposes of insurance.

To the mods: thank-you for the holiday from the show-me state... saved me from flexing my expletives muscle.

 

[dirkclod]

OK..this one lost power directly over my head from a hover at 249' Easter of 15 . Landed right where you see it at my feet .

Had a RPG gimbal on it and weighed almost 3 lbs . Would it have done that to that roof I don't know .
Hit my head ...uggggg
Just missed and it came down so fast when I heard the motors quit I looked up and it was passing me coming down .
Now..Old Boy...can ya beat these ..

 

[Rocky Mountain Old Boy]

OK..this one lost power directly over my head from a hover at 249' Easter of 15 . Landed right where you see it at my feet .
View attachment 49468
Had a RPG gimbal on it and weighed almost 3 lbs . Would it have done that to that roof I don't know .
Hit my head ...uggggg
Just missed and it came down so fast when I heard the motors quit I looked up and it was passing me coming down .
Now..Old Boy...can ya beat these ..
View attachment 49469

Dang, you are lucky it didn't hit you! I've had a rib broken from a baseball that sure didn't come close to 3 lbs. (0.3125 lbs) that was probably traveling about the same speed (50 mph).
Take one in the head... well, you wrote the post, so I am assuming you're ok, lol.

 

[Air Ontario]

Why is everyone here so quick to judgement. I hate that about this site.

I think the more likely story is HE IS the owner of the Drone, and he was sharing his story without admitting fault on a forum like this?

Either way I think the pic with the drone on the roof and the battery burning is pretty easy proof. The only thing that makes me suspicious is the DJI GO app screen shots.


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Who's judging. Apparently you.

I spent most of my life so far in law enforcement, including crash investigation , vandalism, yada yada.

My response was to the poster screaming it was clearly vandalism. Was that you?

Read back especially my posts and re assess.

 

[ianwood]

Newer cars definitely have thinner sheet metal. And a falling drone is nothing to be reckoned with. However, my entirely unqualified assessment is that even if the car was hit by a Phantom, it was also danced on by an elephant. Or VW has switched to using baking foil for body panels.

 

[sar104]

Newer cars definitely have thinner sheet metal. And a falling drone is nothing to be reckoned with. However, my entirely unqualified assessment is that even if the car was hit by a Phantom, it was also danced on by an elephant. Or VW has switched to using baking foil for body panels.

I know that the damage looks improbable. I think that the impact energy was likely sufficient to account for the amount of damage, but I'm struggling with the relatively small indentations produced by the apparent contact points (motor hugs and shell center) in relation to the overall wide-area depression of the roof structure. Tough one to call.

 

[TheLightSpeedz]

Who's judging. Apparently you.

I spent most of my life so far in law enforcement, including crash investigation , vandalism, yada yada.

My response was to the poster screaming it was clearly vandalism. Was that you?

Read back especially my posts and re assess.

Well I just don't think everyone here is an expert... And IF you were... You would need more info to make a decision. Right? Of course.

I've seen one fall from a high altitude and they are heavy when falling at 50mph to the ground.

It's hard to say what caused that damage... The truth is no one knows.

Drones falling out of the sky is a scary reality of this hobby.


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[pomonabill220]

I think the more likely story is HE IS the owner of the Drone, and he was sharing his story without admitting fault on a forum like this?

... and getting his head bit off! I understand his hesitation perfectly! Whether or not it was his quad....