Re: Smaller "drones" aren't a thread to aircraft ....
MacCool said:
Narrator said:
I think I'd much rather be hit by a soft squishy bird than a hard edgy quad. The latter, with its hard edges, would be far more likely to injure me. Imagine being hit in the head by the rigid end of a Phantom arm at a combined impact speed of 150kts or more. Before it broke up, that rigidity would probably punch a hole in my head.
Uh huh. Imagine that right before getting hit in the head with the rigid end of that Phantom, you put on a helmet that is made of .25 inch thick aluminum.
My words are to show how the impact of a soft squishy bird is different to the impact of a solid object. As an ex engineer, I point out that it's not the weight of an object that counts, but the force over area. A nail can enter solid wood because the force/area is significantly high, being focused at the tip. Something soft and squishy will spread their whole force over a large splatter area. But something rigid, like a Phantom will concentrate much of its force over the area of a small tip, just like a nail does, which is why it can do far greater damage than a bird. So when you say that a cockpit window can take a force of 1.8kg, is that over the whole window, or over the tiny, almost nail sized area of impact?
To give it some perspective, let's say the tip of a Phantom arm impacts with an area of say 0.5sq-cm, and let's say an aircraft window is roughly 30x30cm (12x12in):
1.8kg over 0.5sq-cm = 353kPa or 51psi pressure
1.8kg over 900sq-cm = 0.2kPa or 0.03psi pressure
So, when they say that a cockpit window can take 1.8kg, I ask over what area?
If it's per sq-cm (a standard unit) then that's 176kPa or 25psi, which is half of what a Phantom can theoretically produce on impact, to break that window.
edit: A bird, incidentally, if it splattered over a 10x10cm area would have the force of 1.8kPa or 0.25psi. No biggy huh.