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Old 05-25-2016, 04:38 PM   #1
Tallor
 
Join Date: May 2016
Default Weather Warning: Bullet Rain

I was watching some WWII dogfights over cities and it got me thinking--could stray bullets from a plane end up flying into cities and generally destroying things? I would assume a nice brick wall would block most WWII aircraft guns, but anyone hiding behind a cabbage crate may need some better cover!

What do you think?
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Old 05-25-2016, 04:51 PM   #2
Anthony
 
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Default Re: Weather Warning: Bullet Rain

Quote:
Originally Posted by Tallor View Post
I was watching some WWII dogfights over cities and it got me thinking--could stray bullets from a plane end up flying into cities and generally destroying things?
Falling bullets are a known hazard (though most of the cases you hear about involve people deciding that shooting guns into the air is a good way to celebrate) but are usually a smaller hazard than, say, a bomber getting past the fighters and dropping a bomb on the city (defensive fighters are up there to shoot down bombers. Offensive fighters are up there to protect the bombers and probably don't care about casualties from falling bullets anyway).
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Old 05-25-2016, 05:06 PM   #3
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Default Re: Weather Warning: Bullet Rain

A bit of quick googling suggests something around 7.6mm to 8mm machine guns for WWII aircraft fighters. That's looking around 6d pi to 7d pi of damage, although stray shots can be assumed to be in half-damage range outside of extraordinary situations.

So average 10-12 HP of damage. That will generally be stopped by brick walls, but they'll plow through wood siding and shingles, and cars, car glass, window glass....
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Old 05-25-2016, 05:11 PM   #4
Anthony
 
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Default Re: Weather Warning: Bullet Rain

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Originally Posted by Bruno View Post
A bit of quick googling suggests something around 7.6mm to 8mm machine guns for WWII aircraft fighters. That's looking around 6d pi to 7d pi of damage, although stray shots can be assumed to be in half-damage range outside of extraordinary situations.
Actually, they are reasonably likely to be falling at terminal velocity; given that a 3,000 fps 7.62 bullet does a hair over 7d, a bullet at a tenth that speed should do around 1d-1.
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Old 05-25-2016, 05:23 PM   #5
David Johnston2
 
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Default Re: Weather Warning: Bullet Rain

Quote:
Originally Posted by Tallor View Post
I was watching some WWII dogfights over cities and it got me thinking--could stray bullets from a plane end up flying into cities and generally destroying things? I would assume a nice brick wall would block most WWII aircraft guns, but anyone hiding behind a cabbage crate may need some better cover!

What do you think?
It's in the freak accident category. More people got hit by the ack-ack fragments.
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Old 05-25-2016, 05:48 PM   #6
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Default Re: Weather Warning: Bullet Rain

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Actually, they are reasonably likely to be falling at terminal velocity
I find that highly unlikely - they're not being fired straight up into the air; even firing 60 degrees from horizontal is enough to keep a round at a much higher percentage; it's kept properly spin stabilized, so it's going pointy end first. With gunfire from plane-to-plane combat, we're looking at slightly above the horizontal to slightly below the horizontal - definitely not terminal velocity.
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Old 05-25-2016, 06:08 PM   #7
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I find that highly unlikely
The thing is, the bullets aren't going to hit the ground unless they were actually aimed at the ground or they until they manage to actually fall that far, and that's going to take a quite long time. A 30-06 loses half of its velocity in the time it takes for it to fall 5'.
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Old 05-25-2016, 07:06 PM   #8
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Default Re: Weather Warning: Bullet Rain

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A bit of quick googling suggests something around 7.6mm to 8mm machine guns for WWII aircraft fighters.
Only accurate for very early-war fighters. Rifle-caliber machineguns were quickly found to be less than adequate for air-to-air combat, and were mostly replaced by 12.5mm or larger machine guns and 20mm+ autocannon. Some later planes retained a token rifle-caliber armament (like the two MG17s on the FW-190 in High Tech).
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Old 05-26-2016, 06:13 AM   #9
Tomsdad
 
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Default Re: Weather Warning: Bullet Rain

Given the large engagement areas and even larger potential dispersement area this all took place in, and the relatively small payloads in question, I'd imagine it was a pretty unlikely event.



Quote:
Originally Posted by Anthony View Post
The thing is, the bullets aren't going to hit the ground unless they were actually aimed at the ground or they until they manage to actually fall that far, and that's going to take a quite long time. A 30-06 loses half of its velocity in the time it takes for it to fall 5'.
I think the point is you looking at two very different scenarios, yours is about guns fired up from the ground eventually falling back down to the ground.

The one in the OP is about guns fired in the air above the ground hitting the ground.

Your own link makes the point:

Bullets fired at angles less than vertical are more dangerous, as the bullet maintains its angular ballistic trajectory, is far less likely to engage in tumbling motion, and so travels at speeds much higher than a bullet in free fall.


Your scenario is more likely to be the former, the OPs is more likely to be the latter (IMO). On top of that the bullets flight is more likely to be just going high to low, not low-high-low)

Don't get me wrong I'm not suggesting they'd hit the ground at full muzzle velocity or anything like that though!

Last edited by Tomsdad; 05-26-2016 at 09:02 AM.
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Old 05-26-2016, 08:46 AM   #10
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Default Re: Weather Warning: Bullet Rain

Are we now suggesting the need to determine bullet angles of velocity and calculations of kinetic energy in order to solve the problem of stray fire from fighter jets?

Quote:
Originally Posted by Bruno View Post
A bit of quick googling suggests something around 7.6mm to 8mm machine guns for WWII aircraft fighters. That's looking around 6d pi to 7d pi of damage, although stray shots can be assumed to be in half-damage range outside of extraordinary situations.

So average 10-12 HP of damage. That will generally be stopped by brick walls, but they'll plow through wood siding and shingles, and cars, car glass, window glass....
^ This method gets my up vote. Uses existing rules and is quick to figure out.
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