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Confirmed drone collision with aircraft

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Confirmed drone collision with aircraft

Old 8th Jan 2017, 18:49
  #41 (permalink)  
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helimutt: Well said. And others "well said" too.
My original post, for which I got a bit of stick was making the point that, while something has obviously hit this nose, one has to take into account the relative trajectories and speeds of the 2 colliding bodies. The aircraft is presumably making around 150kts in one direction while the object in collision was making an unknown speed and presumably perpendicular to the aircraft. So all ideas of an aircraft "smashing" into an object at 150kts are null and void. I suspect that, if the 2 tracks were not exactly 90 degrees to each other, then the damage to the aircraft would extend further aft of the impact point, sort of "smeared" along the fuselage.
So, if the angle of incidence was at right angles, the speed of the hit would be around 25mph, hence my remark about if the aircraft was flying at 150mph sideways.
And bird strikes are not the inevitable cause of serious damage etc that some may think.
I recently observed a Cessna Citation departing an airport in England and shortly after take off the pilot called the tower and said he thinks he had hit a kestrel as he lifted off. (I had to marvel at his ability to identify a kestrel flashing by at something in excess of 100mph. I don't remember seeing a kestrel there before but I have seen kites in great profusion). Anyway, an inspection discovered a dead bird at the side of the runway and when this was reported to the pilot, he said no harm seems to have been done so he would continue to his destination.
Finally, the radome is made of resilient stuff, either carbon fibre or GRP and I think a piece of plastic hitting a curved section of GRP at perhaps 25mph is not going to do much more than scratch it.
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Old 8th Jan 2017, 19:18
  #42 (permalink)  

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For one object travelling at 150 kts, to collide into another with a relative speed of 25 kts, the other one would had to be moving in a very similar direction at 125 kts in the first place, no?
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Old 8th Jan 2017, 20:40
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In the scenario presented by KelvinD, A/C moving forward at 150 knots, the drone on a path from the right at 90 degrees to it (heading relative to path of A/C), then the relative impact velocity would be sqrt(150**2+25**2) = 152 knots, and the apparent angle of impact as seen by the A/C would be 9.5 degrees to the right, where of course it would appear to be sitting for however long it was visible from the cockpit (assuming constant motions).
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Old 8th Jan 2017, 23:36
  #44 (permalink)  

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Welcome, blackhole Thanks for the math. So, in order for a hit at 90 deg with relative 25 kts, (which the picture rules out with absolute certainty anyhow): The iterceptor would need to be moving at 152 knots converging from the right with 9,5 deg absolute track difference. Same triangle.

But why are we discussing this?

Last edited by FlightDetent; 8th Jan 2017 at 23:47.
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Old 9th Jan 2017, 00:16
  #45 (permalink)  
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This thread is mostly funny and demonstrates quite clearly that neither mathematics nor logical thought have remained on the curriculum.

For all of you still struggling with the basic concept of vectors, try this simple thought process.

If the drone (or ufo, for some of you, if you prefer) was stationary and the aircraft hit it whilst travelling at 150kts, what do you think the impact velocity is?

If the drone is flying, at 25kts, in the same direction as the aircraft, travelling at 150kts; same question?

Why do many of you think that the physics changes simply because the angle of collision changes?

In a similar vein, has anyone here ever played snooker/billiards? If said drone/ufo hits an angled surface, what direction does it move next? (Conserving what remains of its momentum)
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Old 10th Jan 2017, 18:24
  #46 (permalink)  
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Quote from scotneil
Another potential menace to aviation- as shown by yesterday's LAM B737 collision; surely the sale of UAVs should be licensed and the owner/operator made traceable ? How long before some ISIS nutter tries to do some real harm with one of these ?

Please provide evidence that it was a UAV.
Licensing will not prevent those who do not want to bother with such trivia. Plenty of unlicensed and uninsured drivers going about.
ISIS doesn't need to bother with going to the expense & effort of UAV flying. They steal trucks and do much more damage.
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Old 10th Jan 2017, 18:42
  #47 (permalink)  
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Originally Posted by Bankstown Boy
In a similar vein, has anyone here ever played snooker/billiards? If said drone/ufo hits an angled surface, what direction does it move next? (Conserving what remains of its momentum)
That depends on whether it was an elastic or inelastic collision. A snooker ball canoning off another ball is an almost totally elastic collision, so the angle of reflection will equal the angle of incidence (subject to the effects of spin and the friction available to transfer it, obviously).

Whatever hit the nose of the aeroplane in the OP experienced a decidedly INelastic collision with lost of energy dissipated in damaging structures, so the direction and magnitude of the rebound, if there was one, is a matter for conjecture (based only on the information in the photograph).

I'm not sure that simple mechanics can provide any definitive guidance here.
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Old 10th Jan 2017, 22:40
  #48 (permalink)  
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Having seen numerous tests of said colisons, using high speed cameras. the soft structure tampolines inward and forms a ramp in the direction of the impacting vector. As the impacting object loses velocity (energy) it simply follows the ramp outward from the surface of the nose.

If the impacted structure begins to fracture as it deflects, them the object striking, it may not completely follow the ramp effect as some of the object may be injected through the fracture.
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Old 10th Jan 2017, 23:30
  #49 (permalink)  
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Was Not a drone, after investigation

Now avherald says that a drone collision is ruled out and that the radome was wrinkled by air flow pressure. The radome was used and not correctly installed.

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Old 10th Jan 2017, 23:34
  #50 (permalink)  
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Now the haters will have to find another incident to blame on drones.

This kind of unsubstantiated crap is what we are up against.
Blames a drone, then states that the company that made the drone will work with the investigation, then states he doesn't know what hit the airliner. The final twist is how World events relate to Biblical prophesy. I do not knock believers but I do have trouble with the link to alleged drones.

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