quote:

You have undoubtedly examined the site of the occurrence, so I bow to your superior knowledge.

I don't need to witness it to know the math and physics behind it.

A 9mm falling out of the sky does not have enough energy or mass to go through a metal roof, and then retain enough energy to go through a metal wing, and then still enough energy to go through a metal gas tank.

If those of us saying this can't happen are wrong, show us the math that proves your theory possible. Pilots are good at math, so I'm anxiously awaiting.

I just showed you photos of a point blank 9mm gun shot through plastic, foam, and light gauge metal. It made it 3 feet and still didn't penetrate a wall....yet your magic bullet fell from the sky with more energy than the one in my photos above that was fired from a pistol feet away.

quote:

Originally posted by a1abdj:

go through a metal wing, and then still enough energy to go through a metal gas tank.

The wing and the gas tank on this type of airplane are two separate entities? I did not know that. You would think that after hundreds of hours instructing in this make & model of airplane, I would know that.

Once again, I bow to your superior knowledge.

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Once again, I bow to your superior knowledge.

Your words, page 1:

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One 9mm bullet recovered from the gas tank of a Cessna 150

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The wing and the gas tank on this type of airplane are two separate entities? You would think that after hundreds of hours instructing in this make & model of airplane, I would know that.

Yeah....one would think.

So tank...tank cover...roof. Right?

A 147 grain lead bullet has a terminal velocity of about 350fps. That's about 40 foot-pounds of energy. Is that enough for 9mm to penetrate 26 gauge steel?

Gee this is like MR. Wizard!!! Lets get together order pizza and practice reducing fractions. Were you guys Mathletes in high school?? I think they call them STEM students these days.

Just kidding..

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Originally posted by V-Tail:

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Originally posted by erj_pilot:

go to the top of the hangar, and drop a 9mm projectile onto the top of the wing to see if it penetrates?

Fallacy* in your thinking. If you are standing on the ground or even on the hangar roof and drop a bullet, it won't be going very fast when it hits.

And that's my point exactly. If the falling bullet fully penetrates a 26 gauge metal roof, MOST of the kinetic energy would dissipate, thereby leaving very little energy to penetrate the plane wing/tank.

ZSMICHAEL...let's make this fun. I'd rather order hookers and blow.

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ZSMICHAEL...let's make this fun. I'd rather order hookers and blow.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I can go with that. I just thought the other would be more fun for you, a Math and Engineering guy. Let's be honest you guys were not the life of the party.

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If the falling bullet fully penetrates a 26 gauge metal roof, MOST of the kinetic energy would dissipate, thereby leaving very little energy to penetrate the plane wing/tank.

The other option being a shot fired at an angle that travels in an arc. It would have much more penetrating power, but there are a few problems with that theory as well.

If the bullet was traveling at an angle it would not be traveling through the roof and then straight down into something below it.

The second problem which holds true for both theories is that there are two holes in near proximity. A very minor difference between angles at any real distance would put the bullets tens of feet if not hundreds of feet apart. Unless somebody was intentionally aiming and shooting at that building (or something in the path of the building), which we have already been told is not possible. A handgun round being much harder to accomplish that feat with than a rifle at any real distance.

If it was one bullet and one hole I might buy the unintentional random act. Two bullet holes in near proximity tells me it was intentional in some way shape or form.

quote:

Originally posted by ZSMICHAEL:

quote:

ZSMICHAEL...let's make this fun. I'd rather order hookers and blow.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I can go with that. I just thought the other would be more fun for you, a Math and Engineering guy. Let's be honest you guys were not the life of the party.

I will have to confess...I was not an Engineering or Math guy. I was in the THIRD most boring group of nerds...the Accountants.

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I will have to confess...I was not an Engineering or Math guy. I was in the THIRD most boring group of nerds...the Accountants.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Yes. Better than Actuaries who are the guys that failed the Personality test to be Accountants.

Now THAT was LOL funny...

Glad you liked it.

quote:

Originally posted by P250UA5:

Simple fix to repair a puncture hole in an airplane wing, just a patch? Assuming it missed the fuel tanks...

Depends what else it hit. If it hit a spar, it could get very expensive

There's a lot of reference to "terminal velocity" of a falling object. Terminal velocity depends on a stable object, and depends on the surface area and energy of the object. Gravitational acceleration is a constant, independent of weight, but weight is a factor in terminal velocity, as it's a function of energy opposing drag: a heavier object will have a higher terminal velocity, and a smaller object for a given weight will have a higher terminal velocity.

A person in freefall will have a typical stable face-to-earth terminal velocity of about 120 mph, depending on weight and clothing. That equates to 176 feet/sec. In a max track configuration, forward speeds of 60 mph can be achieved, and vertical velocities of up to 250 mph. That's 367 ft/sec. That's for a person in freefall.

When in freefall, if I drop an object that doesn't have something to create drag, the object will accelerate away from me. There isn't a universal terminal velocity, and a very small object with very small wetted surface area has the potential to accelerate to a considerably higher terminal velocity than a person.

The terminal velocity at impact will depend on the elevation above sea level; terminal velociy at low elevations is considerably slower than higher elevations.

I know. Mythbusters. And google. If it's online, it's got to be true.

I've dropped a lot of things from aircraft, from little tiny objects to fifteen tons of water to automobiles, people, and objects that penetrated the ground 15 to 20' or more. A water drop is enough to tear things up, dig deep channels, or kill people, and objects falling off aircraft can very easily be lethal. Hailstones have been known to penetrate roofs and do damage. I don't know what a 115g-147g projectile will do to a hangar roof, but I'd certainly consider the possibility, and I know it's got the capability of reaching much higher terminal velocities than what some here think.

As for penetrating an airplane skin; airplanes are expensive aerodynamic beercans. They're thin. Having been shot in them a few times, I know that damage can be unpredictable and that bullets can pass through aircraft easily enough in the right place, or do very little damage, depending on what they hit, type, velocity angle, structure, etc. I have flown airplanes that had a lot of bullet holes in them and a lot of patches and repairs. Most of that was coming from below and not at terminal velocity, and many areas had protection, self sealing tanks, etc, but there were places that rounds fully penetrated (or did internal damage), no problem.

At Phoenix Skyharbor many years ago, we regularly picked up projectiles near the blast fences at the end of the runway. Hangars got shot through, too. There was a lot of gunfire around there at night, including quite a bit of automatic weapon fire. I heard it regularly. Often nightly. I don't recall bullet holes in hangar roofs, but it's not something that would stick in my memory. Those hangars had some fairly thick metal.

Several older airplanes had roll down windows, others have openable doors, and many airplanes such as single engine Cessna's have windows that and can easily be fired from, to say nothing of helicopters.

I can't speak to the specific case in this thread, but I will say that based on my limited experience, it's certainly possible.

Lawn chair, weather balloons, and a 9mm derringer, without a doubt.