WWII Points To Ponder

[cyberia]

Originally Posted by Jim O

More or less. If the temperature is constant (which it isn't in this system as the temperature at high altitudes is generally much lower) then Boyle's law tells us that Pressure x Volume is constant. So if the pressure is reduced to one third of its original value then the volume will triple. The problem is that the temperature also goes down at the altitude, and lower temperatures cause the Pressure x Volume constant to decrease as well.

The combined gas law is as follows:

Attachment 2416
where P=Pressure, V=Volume, and T=Temperature.

In an unpressurized cabin, pressure goes down, causing volume of gas inside a hollow viscous like the gut to go up. But the reduced temperature mitigates that effect some.

Where's P-D when we need him? He could explain this a lot better than I can.

I'll PM him a link. He eats this stuff up.

[Pirate-Drakk]

You Rang...


Good discussion guys, thanks for inviting me Cyberia!

Jim O basically nailed it but I'll add a few clarifying details.

First invoke the "Ideal Gas Law":
PV=nkT

P=Pressure
V=Volume
T=Temperature
n=number of atoms in the volume
k=Boltzman's constant

(This is where Jim O's equation was derived from.)

Since n and k are constants, forget about them since they don't change. The rest of the variables are linearly proportional.

Therefore, if you had a balloon full of gas, took off in a bomber and flew to an altitude where the P = 1/3 then the Volume would change by a factor of 3, or 300% (3/1). However, that is for CONSTANT "T" (hence the misunderstanding)!

In fact, the temperature drops about 6.5 degrees Kelvin (and Celcius) per 1,000 feet so at 20,000 feet the temperature has gone DOWN 130 degrees. Water freezes at 273 Kelvin so if it was a cold day (32 degrees F = 0 C = 273 K), the temperature drops by about a factor of 2 so the gas only expands 150%, not 300 percent. The higher you go the colder it gets so while P decreases, so does T and therefor the V doesn't increase as much as one might think.

OK, so much for a balloon. Now think of the gas in your stomach (most of what is in your stomach/intestines is liquid). It is inside a pressure vessel at a constant 98.6 degrees F so it behaves a bit differently then a balloon. If the pressure inside your gastrointestinal tract exceeds the outside pressure, the overpressure will be relieved in the normal fashion, a "fart" or a "burp" or both. In an extreme case (drank a bottle of soda/beer before take off) one might vomit to relieve the pressure which would be construed as "altitude sickness". So, even though the volume might increase, the pressure is maintained by "venting".

For one to die of overpressuring the stomach, you would have to "plug all the vent holes" first which is highly unlikely. At VERY high altitudes (100,000 feet?) one will eventually get the "bends" because the blood will boil in a low pressure atmosphere. However, a WWII bomber would never get close to that altitude.

By far the greatest danger of flying 10,000+ feet is "Hypoxia" which is a fancy name for "lack of oxygen". Above 10,000+ feet the amount of Oxygen you can get into your lungs/bloodstream is not enough to sustain consciousness and eventually you pass out and die. The higher you get, the worse the problem. At 30,000 feet you would probably only last a couple minutes due to lack of Oxygen. It's just like being strangled to death except you don't feel the tight grip around your windpipe as you life is slowly sucked away...


I hope this helps.

Anytime you guys have a physics/science type question, don't hesitate to PM me!

As Cyberia correctly pointed out:

Originally Posted by cyberia

I'll PM him a link. He eats this stuff up.

[cyberia]

There you have it folks.

What other WWII site debunks internet myth with both a doctor and scientist in the house!!!

[Panzermacher]

P-D, I doff my Chapeau............Even a Hick like me got that explanation.....


Vielen Dank.....

[Brett]

Originally Posted by cyberia

Following a massive naval bombardment, 35,000 US and Canadian troops stormed ashore at Kiska. During the first hour of the assault 21 men were killed.

The Allies estimated casualties would have been much higher had there in fact been any enemy troops around. The Japanese abandoned the island several weeks before.

The 21 deaths were ruled as accidental and/or friendly fire.

One story I head of this op was of a US 10th Mt. Division squad warily
advancing on Kiska. Suddenly the Sarge yells "Look! Over There!"

The squad hits the deck, expecting an enemy MG to open up any
second -- except the Sarge who is pointing "That's a Pele's falcon.
That's rare! That's very rare!!"

[cyberia]

Originally Posted by Brett

One story I head of this op was of a US 10th Mt. Division squad warily
advancing on Kiska. Suddenly the Sarge yells "Look! Over There!"

The squad hits the deck, expecting an enemy MG to open up any
second -- except the Sarge who is pointing "That's a Pele's falcon.
That's rare! That's very rare!!"

Now that's funny.

[Brett]

Originally Posted by MAGNA

Oops. Makes you wonder what proportion of casualties are due to friendly fire / accidents in other landings.

The book “Touched with Fire: The Land War in the South Pacific” says
studies of the fighting on New Georgia & Bougainville in the Solomon
Islands gave an estimate of ~ 12 % casualties due to Allied friendly fire.
KIA were up to 24% because own troops were at closer range.

I would imagine this would be the upper range of friendly fire casualties
because this front had some of the poorest visibility because of thick
jungle. It was also overwhelmingly an infantry war.

While obviously artillery & aircraft fire on their own troops, I would
guess they could take more time to positively identify enemy positions.
Infantry clashes could very well depend on who fires first, so their
was an incentive to shoot as quickly as possible.

One thing the book mentioned was that shotguns were used in the
close quarter combat of the SW Pacific. They were less deadly at
longer ranges, & thus reduced the risk that a stray bullet would hit
your own hidden troops behind what you were shooting at. I have
not heard of them being used on other fronts.

[Geek44]

I believe they used shotguns in Vietnam for the same reasons.

[cyberia]

I have seen one or two photos of American troops using them in Europe.

[Geek44]

I'm almost certain that they contravene the Geneva Convention too. Having said that, I'd be telling them where they can put their convention if I thought using the ol' blunderbuss would have saved my scrawny behind or those of my mates.