Gravity was just a small part of what I wrote, picking it out of context, and as the only bit to respond to, more fits your charge.
with forward velocity equaling 520 mph?
For a falling plane, gravity adds to speed before impact and adds 1G to impact force. For a plane flying into a building more or less level, the speed you name is initial speed. This was of course an academic point making part of my argument countering your dismissal of impact angle as a factor, not a specific Pentagon impact argument.
this is the FIRST incident of a plane "vaporising"
Vaporising??? Are you now taking figurative speech literally? I again refer you to the photographs of wreckage from the wings. *Lunatic*, n. One whose delusions are out of fashion.
there is a burn pattern on the building but nothing that would indicate the geometry of the object that caused it.
No wreckage? I must be hallucinating:
Here I must be seeing paper clips and the piece of the Global Hawk:
Bur damages? These aren't burn damages:
*Lunatic*, n. One whose delusions are out of fashion.
I don't see anything except some soot on a building that was hit by something which some people tell me was an airplane. I can't see anything on the building that convinces me of that. There is some debris, but very little for such a large object such as a 757.
Sorry but that's what I see
This may have been debunked already, in which case I'm happy to see links explaining how it was done.
But otherwise, this one has me baffled.
Normal airport landings use a system called ILS which guides the pilot to the runway, and optionally autolands if visibility is poor, or the pilot is feeling lazy.
The Pentagon obviously had no ILS. So we're talking about aiming something with the handling characteristics of a very, very large and unwieldy object, travelling at a very high speed.
I'd estimate the target corridor subtends an angle of a couple of degrees. Too high and you overshoot. Too low and you crash into the ground well ahead of the target, spraying the facade with debris, but not doing any structural damage.
You have to get this angle right while flying at between 300 and 500mph. This doesn't give you a lot of time to make pitch and altitude corrections during the final approach.
You can't use the altimeter to improvise a glideslope because there are no clear horizontal cues outside of the windows that you can check against - and everything is happening too fast to run a checklist anyway.
So you're:
Not using instruments or other aids
Approaching at a rate at which everything is happening between 2 and 4 times faster than for a typical landing.
Hitting a target corridor, which has to be accurate to (let's be generous) a few degrees
In something with the handling characteristics of an airborne express train
This may be exactly what happened. But if so, it's extremely impressive flying.
The fact that he hit so low suggests that he almost missed the target, which is not surprising, as you point out. In the long run, we're all dead. John Maynard Keynes
The Pentagon may cover the biggest surface area of any building, but it's not particularly tall. In fact it only has four storeys, at maybe fifty feet. There's a scale photo from a recent study here. For comparison the tail fin on the 757 is just over 44ft.
Let's be conservative and say the approach speed is 300mph, or five miles a minute.
Let's say you're a minute away from your target at an altitude of a couple of thousand feet. How tall does a four storey building look five miles away at a shallow angle?
Fifteen seconds from impact, that four storey building is still more than a mile away.
Because I'm in a pedantic mood, I've worked out the visible width of the target corridor from a mile away. It's a little more than half a degree. And that's just to hit the damn thing at all, never mind score a bullseye on the ground floor.
Let's call it a degree if you assume that some overshoot into the body of the building still counts as a success. (And that's generous considering the actual shallow angle of approach.)
Unlike a car, which is fairly responsive, any altitude and pitch correction is going to take at least a few seconds to work itself through your brain, the avionics, the engines and flaps. Mostly likely you'll overshoot any correction and have to compensate in the other direction, which will eat further into your time allowance. What you certainly can't do is throw a 757 around the sky like a sports car.
Still, being even more generous, the reality is that if you're more than a few degrees out a mile away, you've already missed - by a long way.
As I said - impressive flying.
Do you if the pilot was aiming for the ground floor?
And if so ... how?
(Just being my usual amiable self ;-)
