Flight 93 the physics of the impact

[Dave Rogers]

I'll tell you what. You people drop your model airplanes from rest from 1.5 meters high.

Because that's a good way to simulate a 40 degree impact angle in Simon666's alternate universe, apparently.

Dave

 

[Natan]

Because that's a good way to simulate a 40 degree impact angle in Simon666's alternate universe, apparently.

Dave

Did I attempt to model the Flight 93 impact exactly that way? Strawman. People here are questioning the physics and are argumenting with toy airplanes. I just gave a simple example. Go pick on someone else.

 

[Dave Rogers]

Did I attempt to model the Flight 93 impact exactly that way? Strawman. People here are questioning the physics and are argumenting with toy airplanes. I just gave a simple example.

Then please post your off-topic proposals for experiments on model airplanes that have nothing to do with 9/11 in a more appropriate forum.

Dave

 

[Oystein]

Wow, your observations are not going to change the equations of motion V² / 2gµ for linear motion along a straight line with friction and V²/g sin (2 Theta) for range of a ballistic arc in vacuum.

You quickly lost context. The suggestion to observe a toy plane came in response to this:

Sure buddy, a near vertical impact will result in a horizontal tumbling and moving across the ground. Conservation of momentum is on your side.

It seemed like you doubted that a vertical impact could generate considerable lateral momentum in broken-off pieces.
That was obviously a dumb suggestion.

Interesting you suggest I use observations but am forbidden to use observations of other vertically impacting planes leaving no debris of such size. I guess what's good for the goose ain't good for the gander.

Strawman.

Where did I or anyone else forbid you "to use observations of other vertically impacting planes leaving no debris of such size"?

They are optimum cases, ballistic trajectories in vacuum and horizontal movement along a straight line. A real model would be a combination of both and would still go along the lines of something times V²/g for distance traveled. Nice try hand-waving physics away. Keep waving harder and you'll take off unlike your toy airplane.

Elastic reflection from collision and ballistic travel aren't the only modes that am engine part could "tumble across the ground".

In addition, I am highly doubtful that you'd be able to find parameter values close to the real thing from plausible assumptions about a realistic model to apply your equations to. That's why throwing these simple formulas at us is a foolish thing to do. The physics of such an impact is anything but simple.

 

[Natan]

It seemed like you doubted that a vertical impact could generate considerable lateral momentum in broken-off pieces.
That was obviously a dumb suggestion.

It's possible. In an inelastic collision much less so.

Elastic reflection from collision and ballistic travel aren't the only modes that am engine part could "tumble across the ground".

I have granted that already "It's possible, but only to a certain extent.". Sunstealer made a very good point.

In addition, I am highly doubtful that you'd be able to find parameter values close to the real thing from plausible assumptions about a realistic model to apply your equations to. That's why throwing these simple formulas at us is a foolish thing to do. The physics of such an impact is anything but simple.

At least I gave it a shot as to a reasonable attempt. I admit I have grossly ignored rotational energy. It took you a while to come up with an answer, Sunstealer gave the best argument.

 

[Dave Rogers]

Incidentally, can someone explain what Simon666's "nearly vertical impacts" have to do with the 40º impact of flight 93? It seems to be another classic example of a truther making up a strawman account of 9/11 and insisting that it's "the official story" when it's not what actually happened.

Dave

 

[Natan]

Anyway, I'm still not really convinced of the likeliness of the engine being found that far, not convinced at all of those bandanas being recovered intact or a piece that large surviving the impact as officially alleged. I'll try and post some crash photos of near vertical high-speed impacts.

 

[Dave Rogers]

Anyway, I'm still not really convinced of the likeliness of the engine being found that far, not convinced at all of those bandanas being recovered intact or a piece that large surviving the impact as officially alleged.

Should we alert the press?

Dave

 

[Natan]

Incidentally, can someone explain what Simon666's "nearly vertical impacts" have to do with the 40º impact of flight 93? It seems to be another classic example of a truther making up a strawman account of 9/11 and insisting that it's "the official story" when it's not what actually happened.

Dave

Fine, I'm wrong about the angle. I've seen it described by witnesses as "near vertical". Wrong assumption. The distance allegedly traveled by the engine still seems off.

 

[RedIbis]

I'll put the Flight 93 crash site up there with WTC 7 as the two most perplexing and unconvincing aspects of the official story.

So I have a few layman's questions, that I'm sure our resident experts will provide well sourced and logical explanations for.

1) How did the engine (arguably the densest and heaviest piece of the plane) bounce 300 yards away but smaller lighter pieces bore into the ground 20 to 30 ft?

2) Instead of displacing lage amounts of dirt, how did the soil follow the impact and cover up the plane, burying it deep into the ground?

3) Why didn't EPA soil contamination analyses report fuel contamination?

4) Why is the rim of the crater undisturbed, unburned grass?

There are countless more questions that can be asked and only speculation and wide stretches of imagination to come up with explanations for the strange case of Flight 93.

In the interest of full disclosure, I went toe to toe with Gravy when I first joined this forum and he showed me every picture he could dig up and every report he could find, but the totality of that "evidence" amounted to a third of a dumpster of scrap and few five gallon buckets. I've seen every picture and read nearly anything associated with the crash site, and my above questions do not have sourced, logical responses. Maybe I missed something.

 

[Oystein]

Anyway, I'm still not really convinced of the likeliness of the engine being found that far, not convinced at all of those bandanas being recovered intact or a piece that large surviving the impact as officially alleged. I'll try and post some crash photos of near vertical high-speed impacts.

Spare yourself and us the effort.

Try to come up with a plausible alternative hypothesis that is not obviously lousy and contradicted and inconsistent and downright dumb.


You see, in 11 years, legions of truthers have pointed to gazillions of things they find vaguely suspicious, but none have managed to make all these alleged anomalies converge onto an alternative hypothesis that is at the same time internally consistent, not contradicted by stronger evidence, and complete (more or less). This lack of convergence of evidence on the truther side is what perhaps most distinguishes it from the commonly accepted story, and explains why the commonly accepted story is the the commonly accepted story: It is supremely complete, consistent, and has the totality of all available evidence converging on it.

Bandanas or engines that YOU cannot comprehend are not at all a problem to this.

As the experience airline investigator that YOU quoted pointed out: Finding debris in such manner is expected.



Now if you post a million photos from other crash sites and none has a bandana in it - does that support your case? Whaddaya think?

 

[Dave Rogers]

Fine, I'm wrong about the angle. I've seen it described by witnesses as "near vertical". Wrong assumption. The distance allegedly traveled by the engine still seems off.

So it seems the outputs of your reasoning process are independent of the inputs. There's a word for that.

Dave

 

[Andy_Ross]

For redibis and Simon666.

Do you think flight 93 Crashed?

If you do why would there be any need to tamper with the crash site?

IF you don't what happened to flight 93 it's passengers and crew? Where are they now?

 

[tfk]

The fan, compressor and turbine sections all rotate perpendicular to the forward direction.

Rotate ... VERY fast.

Simon, why do you use the equations of motion that describe a solid, non rotating ball to describe the motion of non-spherical, rapidly rotating portion of an engine that has been chaotically ripped out of its housing?

You may have noticed a couple of things:

1. There have been several crashes of planes wherein the plane hit the ground at high speed, steep angle, but intact (i.e., didn't break up in mid-air).

2. The speed & impact angle of those planes just an instant before the plane's nose hit the ground was all essentially the same (again, ignoring engines, which have very high rotational velocity component added to their linear speed).

3. And yet, even tho all those (non-engine) pieces & parts have the same incident angle & speed, the resulting parts STILL get scattered far & wide by the impact.

What does the above say about using just a couple of variables (like impact angle, speed & coefficient of restitution) & simplistic, deterministic equations of motion to predict (or post-dict) their final location?

Finally, how many forensic airline crash investigations have you personally been a part of? Did you calculate the final positions of the individual debris components for any of these investigations?

I will freely admit that I have been a part of none. Nonetheless, my background orders me to listen very carefully ONLY to experts who have studied prior plane crashes extensively.

I would be much more impressed with your assertions if you could cite any recognized aviation crash analysis authority that claims that there was anything significantly anomalous with the location of the engines.

Or who agrees with any of your assertions, for that matter.

 

[ElMondoHummus]

Should we alert the press?

Dave

As an aside: It's yet another one of the thousands of iterations of your unevaluated inequality fallacy. There are times when I think conspiracy peddlers actually think citing equivalences to unevaluated standards is actually serious analysis, this truther being one of them.

ETA: For those - like the new members - who are wondering what the heck I'm talking about, it's a logical fallacy Dave himself coined a while ago.

Your comment is a classic example of the unevaluated inequality fallacy. You reference two quantities, neither of which you have taken the time or trouble to evaluate, then pretend suspicion based on your unfounded rejection of the conclusion that one quantity has been found to be greater than the other. In this case, the two quantities are (a) the difference between the potential energy released and the amount stored as elastic energy in the lower structure, and (b) the energy required to collapse supports. You seem to be claiming, without actually stating your claim, that it's self-evident that (a) must be less than (b). Sorry, but you can't make that claim until you've done the maths.

 

[MRC_Hans]

Maximum range of anything on a ballistic path is x = v²/g. For 300 yards or 273.8 meters, given g = 9.81 m/s², this means a lowerbound velocity limit of 51 m/s assuming optimum bounce back angle of 45 degrees. Given an impact speed of 250 m/s according to the official story, this means a plastically deforming metal engine on soft ground would have a coefficient of restitution at an absolute minimum of 51/250 ~= 0.2. For anything other than 45° optimum bounce back angle, you'll soon enough find your Flight 93 engine is behaving like an elastically deforming metal object impacting rubber in a perfect vacuum. Sure.

Any thoughts Hans?

That is a bounce back efficiency of 20%. Hardly anything near metal on rubber, which may yield aroung 90%, so one thought is that, since you can figure this out, you know you are speaking crap.

Another thought is that this is a very chaotic event and you cannot make a two-body calculation on anything.

Even in a two-body event, rotation may propel parts of the bouncing body surprisingly far.

Hans

 

[Spanx]

Speaking as an uneducated leyman, can redibis point me in the direction of any pictures of mangled body parts from any part of 911.

If you can't would that mean that nobody died.

 

[MRC_Hans]

Fine, I'm wrong about the angle. I've seen it described by witnesses as "near vertical". Wrong assumption. The distance allegedly traveled by the engine still seems off.

40 degrees is very near vertical, for flying purposes.

If your purpose is NOT to crash, it is not an angle you should occupy at 500mph for very long.

Hans

 

[Dave Rogers]

40 degrees is very near vertical, for flying purposes.

Or for large values of 40.

Dave

 

[MRC_Hans]

1) How did the engine (arguably the densest and heaviest piece of the plane) bounce 300 yards away but smaller lighter pieces bore into the ground 20 to 30 ft?

Take a dense object and a not so dense object, say, a baseball and a sock. See which you can throw (or bounce) the farthest.

2) Instead of displacing lage amounts of dirt, how did the soil follow the impact and cover up the plane, burying it deep into the ground?

A little counterintuitively, hard ground makes for larger craters than soft ground. This is because the hard ground is able to transmit the impact energy further.

3) Why didn't EPA soil contamination analyses report fuel contamination?

The impact energy would heat the fuel to above its boiling point, instantly evaporating it all. Most of it would then burn in a fireball.

4) Why is the rim of the crater undisturbed, unburned grass?

It is hardly undisturbed.

http://www.youtube.com/watch?v=HpBeF5scrtA

It is not burnt because a fireball rises up.

Maybe I missed something.

I think so, yes.

Hans