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Subway sandwiches on Amtrak, pressurized airplanes and Cub Scouts

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Posted by TomDiehl on Tuesday, December 6, 2005 9:12 PM
QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

Yes, Fed-ex planes are pressurized and climate controlled.


The cockpit is necessary, but the cargo compartment is dependant on the design of the aircraft. It isn't necessary to pressurise or climate control a cargo compartment like it is a passenger compartment.


On commercial aircraft, cockpit isn't a pressure vessel. The fuselage is. You can't just pressurized the cockpit.


On commercial airliners, until recently, the cargo compartment, located right below the passenger compartment, wasn't pressurized, a reason many people lost pets when taking them along on an aircraft and checking them through in a pet carrier.

And trust me, if they're not heated in flight, they get MIGHTY cold in there.

An aircraft isn't a pressure vessel to the point of a steam locomotive, you're only talking abut 10 PSI difference.


The cargo area was pressurized, it wasn't HEATED to full cabin temp and the pets died of hypothermia. At 35,000 ft. nothing would ever survive the flight without pressurization.

10 psi over an area of 100 ft x 10 ft (airplane floor) is 1,440,000 lbs. That would be SOME floor taking that load.


Sounds impressive if your physics were anywhere near accurate. The wall or floor would have to maintain the seal against 10 PSI. An aircraft fuselage is only a thin aluminum.


ARGH! I don't even know where to start with you!

..only have to maintain a seal? Utter nonsense! The pressure differential acts on the whole surface. When you pressurize a cylinder, the stress on the skin is entirely tension and the entire skin carries the load. If you "sealed" the floor and then depressurized the area under it, the floor would be acting as a beam - top in compression, bottom in tension - with that 1.4M# load distributed on in it. That would be quite a floor!

Don't make me get out my strength of materials book.....



So you're saying that a 1/4 inch thick aluminum skin riveted to an inside framework can 1.4 million pounds of force? Impressive if the vessel was large enough, but the strength of materials book will give you ratings in pounds per SQUARE INCH, the same as the measurement of air pressure.

And I fail to see how the floor, reinforced to support the weight of the cargo or passengers would be weaker than the outside fuselage of the aircraft.


You are confusing the engineering discipline "strength of materials" with "materials science". Material Science deals with the properties of the materials. Strength of Materials is all about how to calculate stress and strain in various objects - like cylinders, beams, floors, columns, etc.

Getting out my Singer "Stength of Materials" book. Looking on p 20 to see how to calculate stress in a thin walled cylinder.

If the cylinder was made of 1/4" thick aluminum, the hoop stress is only 2300 psi.

Aluminum is good for better than 30,000 psi

Working backward, you only need 0.019" thick aluminum to carry the hoop stresses from a 10 psi internal pressure.

You COULD build an airplane where the area under the floor is not pressurized and the area above is, but you'd have to add so much structure to support the floor and distribute the load to the fuselage skin, that you'd significantly cut into your payload capacity.

It's MUCH simpler, lighter and cheaper to just pressurize the whole cylinder - which is why airplanes are built that way!

You COULD just take the word of a degreed Mechanical Engineer [:D]





But of what value is it? As many times as I've been in the cockpit of an aircraft, I don't recall ever seeing a gauge marked "Hoop Pressure." Is this more of the info "never used outside the school?"
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by dharmon on Tuesday, December 6, 2005 11:14 PM
Tom,

It's cheaper, lighter and ultimately stronger to pressurize the entire cabin, not to mention to ease maintainance. I suppose if you really wanted to make the floor a pressurized bulkhead you could...but instead of the weight of whatever is on the deck being supported by the floor and structural members, it's being supported by the pressure bulkhead, which means it has to be strengthen to accomodate the additional stresses. You couldn't access anything outside the main deck in flight, and any maintenance action which required opening or cutting a hole in the floor would require a pressure check.

Some of the military transport aircraft, such as the C130 can pressurize the cockpit separately I believe, in order to conduct high altitude drops and such, but will repressurize the cabin after buttoning up. But even the C130's floor as low as it is, is raised above the outer hull. But for civilian applications the need isn't there to justify the expense.

Dan
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Posted by oltmannd on Wednesday, December 7, 2005 8:19 AM
QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

Yes, Fed-ex planes are pressurized and climate controlled.


The cockpit is necessary, but the cargo compartment is dependant on the design of the aircraft. It isn't necessary to pressurise or climate control a cargo compartment like it is a passenger compartment.


On commercial aircraft, cockpit isn't a pressure vessel. The fuselage is. You can't just pressurized the cockpit.


On commercial airliners, until recently, the cargo compartment, located right below the passenger compartment, wasn't pressurized, a reason many people lost pets when taking them along on an aircraft and checking them through in a pet carrier.

And trust me, if they're not heated in flight, they get MIGHTY cold in there.

An aircraft isn't a pressure vessel to the point of a steam locomotive, you're only talking abut 10 PSI difference.


The cargo area was pressurized, it wasn't HEATED to full cabin temp and the pets died of hypothermia. At 35,000 ft. nothing would ever survive the flight without pressurization.

10 psi over an area of 100 ft x 10 ft (airplane floor) is 1,440,000 lbs. That would be SOME floor taking that load.


Sounds impressive if your physics were anywhere near accurate. The wall or floor would have to maintain the seal against 10 PSI. An aircraft fuselage is only a thin aluminum.


ARGH! I don't even know where to start with you!

..only have to maintain a seal? Utter nonsense! The pressure differential acts on the whole surface. When you pressurize a cylinder, the stress on the skin is entirely tension and the entire skin carries the load. If you "sealed" the floor and then depressurized the area under it, the floor would be acting as a beam - top in compression, bottom in tension - with that 1.4M# load distributed on in it. That would be quite a floor!

Don't make me get out my strength of materials book.....



So you're saying that a 1/4 inch thick aluminum skin riveted to an inside framework can 1.4 million pounds of force? Impressive if the vessel was large enough, but the strength of materials book will give you ratings in pounds per SQUARE INCH, the same as the measurement of air pressure.

And I fail to see how the floor, reinforced to support the weight of the cargo or passengers would be weaker than the outside fuselage of the aircraft.


You are confusing the engineering discipline "strength of materials" with "materials science". Material Science deals with the properties of the materials. Strength of Materials is all about how to calculate stress and strain in various objects - like cylinders, beams, floors, columns, etc.

Getting out my Singer "Stength of Materials" book. Looking on p 20 to see how to calculate stress in a thin walled cylinder.

If the cylinder was made of 1/4" thick aluminum, the hoop stress is only 2300 psi.

Aluminum is good for better than 30,000 psi

Working backward, you only need 0.019" thick aluminum to carry the hoop stresses from a 10 psi internal pressure.

You COULD build an airplane where the area under the floor is not pressurized and the area above is, but you'd have to add so much structure to support the floor and distribute the load to the fuselage skin, that you'd significantly cut into your payload capacity.

It's MUCH simpler, lighter and cheaper to just pressurize the whole cylinder - which is why airplanes are built that way!

You COULD just take the word of a degreed Mechanical Engineer [:D]





But of what value is it? As many times as I've been in the cockpit of an aircraft, I don't recall ever seeing a gauge marked "Hoop Pressure." Is this more of the info "never used outside the school?"


Wrong again, reindeer breath! (with appolgies to Johny Carson)

Why in the world would anyone measure the hoop, or circumfrential STRESS (not pressure - although the units are the same) in an aircraft fuselage? You DESIGN for it based on the internal pressure.

This is really, really basic simple engineering - several hundred years old. It is used ALL OVER THE PLACE outside of "the school". Everything from the water pipes in your house to the brake pipe on a frt car use this stress calculation. It's often called "hoop" stress because of it's application in barrel making.

You are either impossibly dense or just rattling my cage....

I feel like I'm stuck in the Bob and Ray "Komodo Dragon" radio play.[:)]

http://www.mindspring.com/~biohaz/komodo.txt

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by TomDiehl on Wednesday, December 7, 2005 4:06 PM
QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

Yes, Fed-ex planes are pressurized and climate controlled.


The cockpit is necessary, but the cargo compartment is dependant on the design of the aircraft. It isn't necessary to pressurise or climate control a cargo compartment like it is a passenger compartment.


On commercial aircraft, cockpit isn't a pressure vessel. The fuselage is. You can't just pressurized the cockpit.


On commercial airliners, until recently, the cargo compartment, located right below the passenger compartment, wasn't pressurized, a reason many people lost pets when taking them along on an aircraft and checking them through in a pet carrier.

And trust me, if they're not heated in flight, they get MIGHTY cold in there.

An aircraft isn't a pressure vessel to the point of a steam locomotive, you're only talking abut 10 PSI difference.


The cargo area was pressurized, it wasn't HEATED to full cabin temp and the pets died of hypothermia. At 35,000 ft. nothing would ever survive the flight without pressurization.

10 psi over an area of 100 ft x 10 ft (airplane floor) is 1,440,000 lbs. That would be SOME floor taking that load.


Sounds impressive if your physics were anywhere near accurate. The wall or floor would have to maintain the seal against 10 PSI. An aircraft fuselage is only a thin aluminum.


ARGH! I don't even know where to start with you!

..only have to maintain a seal? Utter nonsense! The pressure differential acts on the whole surface. When you pressurize a cylinder, the stress on the skin is entirely tension and the entire skin carries the load. If you "sealed" the floor and then depressurized the area under it, the floor would be acting as a beam - top in compression, bottom in tension - with that 1.4M# load distributed on in it. That would be quite a floor!

Don't make me get out my strength of materials book.....



So you're saying that a 1/4 inch thick aluminum skin riveted to an inside framework can 1.4 million pounds of force? Impressive if the vessel was large enough, but the strength of materials book will give you ratings in pounds per SQUARE INCH, the same as the measurement of air pressure.

And I fail to see how the floor, reinforced to support the weight of the cargo or passengers would be weaker than the outside fuselage of the aircraft.


You are confusing the engineering discipline "strength of materials" with "materials science". Material Science deals with the properties of the materials. Strength of Materials is all about how to calculate stress and strain in various objects - like cylinders, beams, floors, columns, etc.

Getting out my Singer "Stength of Materials" book. Looking on p 20 to see how to calculate stress in a thin walled cylinder.

If the cylinder was made of 1/4" thick aluminum, the hoop stress is only 2300 psi.

Aluminum is good for better than 30,000 psi

Working backward, you only need 0.019" thick aluminum to carry the hoop stresses from a 10 psi internal pressure.

You COULD build an airplane where the area under the floor is not pressurized and the area above is, but you'd have to add so much structure to support the floor and distribute the load to the fuselage skin, that you'd significantly cut into your payload capacity.

It's MUCH simpler, lighter and cheaper to just pressurize the whole cylinder - which is why airplanes are built that way!

You COULD just take the word of a degreed Mechanical Engineer [:D]





But of what value is it? As many times as I've been in the cockpit of an aircraft, I don't recall ever seeing a gauge marked "Hoop Pressure." Is this more of the info "never used outside the school?"


Wrong again, reindeer breath! (with appolgies to Johny Carson)

Why in the world would anyone measure the hoop, or circumfrential STRESS (not pressure - although the units are the same) in an aircraft fuselage? You DESIGN for it based on the internal pressure.

This is really, really basic simple engineering - several hundred years old. It is used ALL OVER THE PLACE outside of "the school". Everything from the water pipes in your house to the brake pipe on a frt car use this stress calculation. It's often called "hoop" stress because of it's application in barrel making.

You are either impossibly dense or just rattling my cage....

I feel like I'm stuck in the Bob and Ray "Komodo Dragon" radio play.[:)]

http://www.mindspring.com/~biohaz/komodo.txt


You seem to be impossibly inept at reading a question. What is the value of the 1.4 million pounds of force other than a exercise in mathmatics? Or trying to impress someone with insignificant numbers?

Reference your quote: "10 psi over an area of 100 ft x 10 ft (airplane floor) is 1,440,000 lbs. That would be SOME floor taking that load."

Exactly how would the floor be taking that large of a load, which is far above the cargo capacity of most aircraft, even if it were a pressure bulkhead? A small puncture in the fuselage would cause the plane to explode with that much force inside. Something already disproven on "Mythbusters."
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by oltmannd on Thursday, December 8, 2005 11:38 AM
QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

Yes, Fed-ex planes are pressurized and climate controlled.


The cockpit is necessary, but the cargo compartment is dependant on the design of the aircraft. It isn't necessary to pressurise or climate control a cargo compartment like it is a passenger compartment.


On commercial aircraft, cockpit isn't a pressure vessel. The fuselage is. You can't just pressurized the cockpit.


On commercial airliners, until recently, the cargo compartment, located right below the passenger compartment, wasn't pressurized, a reason many people lost pets when taking them along on an aircraft and checking them through in a pet carrier.

And trust me, if they're not heated in flight, they get MIGHTY cold in there.

An aircraft isn't a pressure vessel to the point of a steam locomotive, you're only talking abut 10 PSI difference.


The cargo area was pressurized, it wasn't HEATED to full cabin temp and the pets died of hypothermia. At 35,000 ft. nothing would ever survive the flight without pressurization.

10 psi over an area of 100 ft x 10 ft (airplane floor) is 1,440,000 lbs. That would be SOME floor taking that load.


Sounds impressive if your physics were anywhere near accurate. The wall or floor would have to maintain the seal against 10 PSI. An aircraft fuselage is only a thin aluminum.


ARGH! I don't even know where to start with you!

..only have to maintain a seal? Utter nonsense! The pressure differential acts on the whole surface. When you pressurize a cylinder, the stress on the skin is entirely tension and the entire skin carries the load. If you "sealed" the floor and then depressurized the area under it, the floor would be acting as a beam - top in compression, bottom in tension - with that 1.4M# load distributed on in it. That would be quite a floor!

Don't make me get out my strength of materials book.....



So you're saying that a 1/4 inch thick aluminum skin riveted to an inside framework can 1.4 million pounds of force? Impressive if the vessel was large enough, but the strength of materials book will give you ratings in pounds per SQUARE INCH, the same as the measurement of air pressure.

And I fail to see how the floor, reinforced to support the weight of the cargo or passengers would be weaker than the outside fuselage of the aircraft.


You are confusing the engineering discipline "strength of materials" with "materials science". Material Science deals with the properties of the materials. Strength of Materials is all about how to calculate stress and strain in various objects - like cylinders, beams, floors, columns, etc.

Getting out my Singer "Stength of Materials" book. Looking on p 20 to see how to calculate stress in a thin walled cylinder.

If the cylinder was made of 1/4" thick aluminum, the hoop stress is only 2300 psi.

Aluminum is good for better than 30,000 psi

Working backward, you only need 0.019" thick aluminum to carry the hoop stresses from a 10 psi internal pressure.

You COULD build an airplane where the area under the floor is not pressurized and the area above is, but you'd have to add so much structure to support the floor and distribute the load to the fuselage skin, that you'd significantly cut into your payload capacity.

It's MUCH simpler, lighter and cheaper to just pressurize the whole cylinder - which is why airplanes are built that way!

You COULD just take the word of a degreed Mechanical Engineer [:D]





But of what value is it? As many times as I've been in the cockpit of an aircraft, I don't recall ever seeing a gauge marked "Hoop Pressure." Is this more of the info "never used outside the school?"


Wrong again, reindeer breath! (with appolgies to Johny Carson)

Why in the world would anyone measure the hoop, or circumfrential STRESS (not pressure - although the units are the same) in an aircraft fuselage? You DESIGN for it based on the internal pressure.

This is really, really basic simple engineering - several hundred years old. It is used ALL OVER THE PLACE outside of "the school". Everything from the water pipes in your house to the brake pipe on a frt car use this stress calculation. It's often called "hoop" stress because of it's application in barrel making.

You are either impossibly dense or just rattling my cage....

I feel like I'm stuck in the Bob and Ray "Komodo Dragon" radio play.[:)]

http://www.mindspring.com/~biohaz/komodo.txt


You seem to be impossibly inept at reading a question. What is the value of the 1.4 million pounds of force other than a exercise in mathmatics? Or trying to impress someone with insignificant numbers?

Reference your quote: "10 psi over an area of 100 ft x 10 ft (airplane floor) is 1,440,000 lbs. That would be SOME floor taking that load."

Exactly how would the floor be taking that large of a load, which is far above the cargo capacity of most aircraft, even if it were a pressure bulkhead? A small puncture in the fuselage would cause the plane to explode with that much force inside. Something already disproven on "Mythbusters."



Did ever take any Physics anywhere? Even in High School? How about math? Algebra in 9th grade?

What part of 10psi x 10' x100' x 144sqin/sqft = 1.4M# is so hard to grasp? (# is shorthand for "pounds of force")

That's the load on the FLOOR! Do you think that the 10 psi might act on other surfaces of the fueslage? Which ones? What direction would that force act? How does that compare to the force on the floor?

You need to know this stuff if you're going to be able to get your Webelos "Scientist" badge at next month's pack meeting[;)]
http://www.usscouts.org/advance/cubscout/technology.html#Scientist

Why aren't propane tanks square? Wouldn't it they be more space efficient?

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by TomDiehl on Thursday, December 8, 2005 2:45 PM
Sorry, but juvenile name calling and other insults lead me to believe that I'm reading a large measure of the BS factor rather than pertinent facts and figures.

Taking math or physics in school was NOT the question, hence my statement that you can't read. I'm not disputing your mathmatics. The question WAS "what is the significance of the 1.4 million pound figure?" The pressure bulkhead, be it the fuselage or the floor, has to hold back 10 PSI of pressure differential between the inner and outer surfaces. Pulling a formula out of a physics book that yields a huge number might impress some, but I've seen the federal deficit, so "not impressed."

The most juvenile remarks have been yours. I guess an intellegent, mature question is beyond your grasp.
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by oltmannd on Thursday, December 8, 2005 2:55 PM
OK, I'll admit a cheap shot with the Cub Scout stuff!

I'm not the only one who told you that passenger airliners are completely pressurized. You don't believe them either?

Maybe I'm the only one stupid enough to argue with a fence post! (another cheap shot, I suppose, but at whom?)

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by TomDiehl on Thursday, December 8, 2005 3:53 PM
QUOTE: Originally posted by oltmannd

OK, I'll admit a cheap shot with the Cub Scout stuff!

I'm not the only one who told you that passenger airliners are completely pressurized. You don't believe them either?

Maybe I'm the only one stupid enough to argue with a fence post! (another cheap shot, I suppose, but at whom?)


And again you didn't read the question. I hope by the time you're old enough to take your SAT's you'll acquire that skill or the only career phrase you'll need is "Ya want fries with that?"

I never said they weren't pressurized, I said it WASN'T NECESSARY to pressurize or heat them.

The question was (now read this S-L-O-W-L-Y) "What is the significance of the 1.4 million pound figure that keep bringing up?" A pressure bulkhead, be it the floor or the fuselage walls, will have to hold back the pressure differential, no matter what the number is you wi***o assign to it.

It's like me asking "What's two plus two?" and you keep answering "fish."
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by Anonymous on Thursday, December 8, 2005 4:15 PM
What I still don't understand is why anyone would ever name a level of Boy Scouting anything remotely sounding like "We Blow"???

Is there even a merit badge involving RRs anymore?

LC
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Posted by Anonymous on Thursday, December 8, 2005 4:34 PM
So what is is? Are aircraft cargo holds pressurized or not? Heated or not? If they are not and there is a great possibility that my wifes little "kick dog," will pari***hen count me in! I want to know which airline has the worst record of live freight arriving safely so I can purchase a ticket and send the peeing, biting, barking little sucker on a one way trip to his little maker. Bye Bye Bennie! Hehehehe
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Posted by TomDiehl on Thursday, December 8, 2005 4:45 PM
QUOTE: Originally posted by Limitedclear

What I still don't understand is why anyone would ever name a level of Boy Scouting anything remotely sounding like "We Blow"???

Is there even a merit badge involving RRs anymore?

LC


Webelo (sp?) is a name for a sort of post-Cub Scout, pre-Boy Scout, a contraction of the words "We belong."

Scouting does still have a Railroading merit badge. Steamtown runs a program to qualify Scouts for it. Check with a local RR club or museum to see if they offer a similar program.
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by Anonymous on Thursday, December 8, 2005 6:04 PM
QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by Limitedclear

What I still don't understand is why anyone would ever name a level of Boy Scouting anything remotely sounding like "We Blow"???

Is there even a merit badge involving RRs anymore?

LC


Webelo (sp?) is a name for a sort of post-Cub Scout, pre-Boy Scout, a contraction of the words "We belong."

Scouting does still have a Railroading merit badge. Steamtown runs a program to qualify Scouts for it. Check with a local RR club or museum to see if they offer a similar program.


Tom -

Thanks. Although its been a few decades I understand what a Webelos scout is. I even was one a long time ago... I still think it is a lousy name.

As for the Merit badge, it's good to know they still offer it.

LC
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Posted by jeaton on Thursday, December 8, 2005 7:21 PM
Speaking of Badges-and Awards. I have decided to ask Bergie to establish a Trains.com "Forum Topic Hijacking Award".

Two members immediately come to mind as the first recipients.

Jay

"We have met the enemy and he is us." Pogo Possum "We have met the anemone... and he is Russ." Bucky Katt "Prediction is very difficult, especially if it's about the future." Niels Bohr, Nobel laureate in physics

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Posted by TomDiehl on Thursday, December 8, 2005 9:21 PM
QUOTE: Originally posted by jeaton

Speaking of Badges-and Awards. I have decided to ask Bergie to establish a Trains.com "Forum Topic Hijacking Award".

Two members immediately come to mind as the first recipients.

Jay


Only TWO?????
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by oltmannd on Friday, December 9, 2005 8:14 AM
How 'bout those Phillies!

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by oltmannd on Friday, December 9, 2005 8:20 AM
QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

OK, I'll admit a cheap shot with the Cub Scout stuff!

I'm not the only one who told you that passenger airliners are completely pressurized. You don't believe them either?

Maybe I'm the only one stupid enough to argue with a fence post! (another cheap shot, I suppose, but at whom?)


And again you didn't read the question. I hope by the time you're old enough to take your SAT's you'll acquire that skill or the only career phrase you'll need is "Ya want fries with that?"

I never said they weren't pressurized, I said it WASN'T NECESSARY to pressurize or heat them.

The question was (now read this S-L-O-W-L-Y) "What is the significance of the 1.4 million pound figure that keep bringing up?" A pressure bulkhead, be it the floor or the fuselage walls, will have to hold back the pressure differential, no matter what the number is you wi***o assign to it.

It's like me asking "What's two plus two?" and you keep answering "fish."


The 1.4M# figure is the load you'd have to design the floor for if you want it to be a pressurized bulkhead.

There are NO commercial passenger airliners that have their floor as a pressurized bulkhead.

If there are no planes with floor that can act as a pressurized bulkhead, then it is ALWAYS necessary to pressurize the cargo area.

You COULD build a car with 7 wheels, too, but why would you?

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by oltmannd on Friday, December 9, 2005 8:37 AM
QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by Limitedclear

What I still don't understand is why anyone would ever name a level of Boy Scouting anything remotely sounding like "We Blow"???

Is there even a merit badge involving RRs anymore?

LC


Webelo (sp?) is a name for a sort of post-Cub Scout, pre-Boy Scout, a contraction of the words "We belong."

Scouting does still have a Railroading merit badge. Steamtown runs a program to qualify Scouts for it. Check with a local RR club or museum to see if they offer a similar program.


My Webelos book says "WE'll BE LOyal Scouts". It's the last 1-1/2 years of Cub Scouting. My 5th grader "graduates" this January - I can finally stop being a Den Mother!

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by TomDiehl on Friday, December 9, 2005 10:09 AM
QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

OK, I'll admit a cheap shot with the Cub Scout stuff!

I'm not the only one who told you that passenger airliners are completely pressurized. You don't believe them either?

Maybe I'm the only one stupid enough to argue with a fence post! (another cheap shot, I suppose, but at whom?)


And again you didn't read the question. I hope by the time you're old enough to take your SAT's you'll acquire that skill or the only career phrase you'll need is "Ya want fries with that?"

I never said they weren't pressurized, I said it WASN'T NECESSARY to pressurize or heat them.

The question was (now read this S-L-O-W-L-Y) "What is the significance of the 1.4 million pound figure that keep bringing up?" A pressure bulkhead, be it the floor or the fuselage walls, will have to hold back the pressure differential, no matter what the number is you wi***o assign to it.

It's like me asking "What's two plus two?" and you keep answering "fish."


The 1.4M# figure is the load you'd have to design the floor for if you want it to be a pressurized bulkhead.

There are NO commercial passenger airliners that have their floor as a pressurized bulkhead.

If there are no planes with floor that can act as a pressurized bulkhead, then it is ALWAYS necessary to pressurize the cargo area.

You COULD build a car with 7 wheels, too, but why would you?


So back to the original question, why is the 1.4 million pound figure appliede to the floor when it's a pressurized bulkhead, and not applied to the fuselage walls when they are the pressurized bulkhead.

The "necessity" I'm refering to is based on the contents of the compartment. Cargo doesn't need heat or pressurization any more than most boxcars or enclosed trailers need it. When you're hauling passengers, the need changes.
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by TomDiehl on Friday, December 9, 2005 10:13 AM
QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by Limitedclear

What I still don't understand is why anyone would ever name a level of Boy Scouting anything remotely sounding like "We Blow"???

Is there even a merit badge involving RRs anymore?

LC


Webelo (sp?) is a name for a sort of post-Cub Scout, pre-Boy Scout, a contraction of the words "We belong."

Scouting does still have a Railroading merit badge. Steamtown runs a program to qualify Scouts for it. Check with a local RR club or museum to see if they offer a similar program.


My Webelos book says "WE'll BE LOyal Scouts". It's the last 1-1/2 years of Cub Scouting. My 5th grader "graduates" this January - I can finally stop being a Den Mother!


I was doing that from memory. It's been a LOOONNNGGG time since my son was that age (he's 28 now).
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by dharmon on Friday, December 9, 2005 10:23 AM
QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

OK, I'll admit a cheap shot with the Cub Scout stuff!

I'm not the only one who told you that passenger airliners are completely pressurized. You don't believe them either?

Maybe I'm the only one stupid enough to argue with a fence post! (another cheap shot, I suppose, but at whom?)


And again you didn't read the question. I hope by the time you're old enough to take your SAT's you'll acquire that skill or the only career phrase you'll need is "Ya want fries with that?"

I never said they weren't pressurized, I said it WASN'T NECESSARY to pressurize or heat them.

The question was (now read this S-L-O-W-L-Y) "What is the significance of the 1.4 million pound figure that keep bringing up?" A pressure bulkhead, be it the floor or the fuselage walls, will have to hold back the pressure differential, no matter what the number is you wi***o assign to it.

It's like me asking "What's two plus two?" and you keep answering "fish."


The 1.4M# figure is the load you'd have to design the floor for if you want it to be a pressurized bulkhead.

There are NO commercial passenger airliners that have their floor as a pressurized bulkhead.

If there are no planes with floor that can act as a pressurized bulkhead, then it is ALWAYS necessary to pressurize the cargo area.

You COULD build a car with 7 wheels, too, but why would you?


So back to the original question, why is the 1.4 million pound figure appliede to the floor when it's a pressurized bulkhead, and not applied to the fuselage walls when they are the pressurized bulkhead.

The "necessity" I'm refering to is based on the contents of the compartment. Cargo doesn't need heat or pressurization any more than most boxcars or enclosed trailers need it. When you're hauling passengers, the need changes.



Not really. What's the most a train or truck is going to see...sea level to maybe 6000 ft. Goods packaged under pressure..for example...air tight bags, plastic bottles, etc...will expand or contract with the altitude changes. I have seen potato chip bags burst at 6000' of cabin altitude. Add a rapid 60 degree temperature change (if it's not heated either), and we get more damage. Particularly liquids. Unless all you are hauling is books..you are going to have unhappy customers. And coming back down is equally destructive.....had a rapid loss of cabin pressuriztion at around FL180 in a descent. Never knew I had an abcess under a filling until in blew the filling and top of tooth off about two seconds after the pressure dipped.

Dan

So...I can not eat a Subway sandwich on a train,
and on Tom's cold airline I would refrain,
but not in Spain,
nor in the rain,
or to add to Jay's pain....
unless a merit badge I could attain.

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Posted by Anonymous on Friday, December 9, 2005 10:26 AM
So, does this thread name change indicate that the Cub Scouts will now be serving the Subway sandwiches on Amtrak???

Perhaps we can pressurize a few planes with all this hot air??

How 'bout that Southwest crash at Midway? Ouch. Some bad driving there....

LC
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Posted by chad thomas on Friday, December 9, 2005 10:41 AM
Or will the cub scouts be subsidizing pressurized Subway sandwiches on Amtrak?[:D]

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Posted by oltmannd on Friday, December 9, 2005 11:04 AM
QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by TomDiehl

QUOTE: Originally posted by oltmannd

OK, I'll admit a cheap shot with the Cub Scout stuff!

I'm not the only one who told you that passenger airliners are completely pressurized. You don't believe them either?

Maybe I'm the only one stupid enough to argue with a fence post! (another cheap shot, I suppose, but at whom?)


And again you didn't read the question. I hope by the time you're old enough to take your SAT's you'll acquire that skill or the only career phrase you'll need is "Ya want fries with that?"

I never said they weren't pressurized, I said it WASN'T NECESSARY to pressurize or heat them.

The question was (now read this S-L-O-W-L-Y) "What is the significance of the 1.4 million pound figure that keep bringing up?" A pressure bulkhead, be it the floor or the fuselage walls, will have to hold back the pressure differential, no matter what the number is you wi***o assign to it.

It's like me asking "What's two plus two?" and you keep answering "fish."


The 1.4M# figure is the load you'd have to design the floor for if you want it to be a pressurized bulkhead.

There are NO commercial passenger airliners that have their floor as a pressurized bulkhead.

If there are no planes with floor that can act as a pressurized bulkhead, then it is ALWAYS necessary to pressurize the cargo area.

You COULD build a car with 7 wheels, too, but why would you?


So back to the original question, why is the 1.4 million pound figure appliede to the floor when it's a pressurized bulkhead, and not applied to the fuselage walls when they are the pressurized bulkhead.

The "necessity" I'm refering to is based on the contents of the compartment. Cargo doesn't need heat or pressurization any more than most boxcars or enclosed trailers need it. When you're hauling passengers, the need changes.


You DO have a large load on all the pressurized fuselage surfaces. The direction in which those forces act and how the forces are carried in the structure are the key. A cylinder is a very efficient design to pressurize. A rectangle is not. It's why all pressure vessels are cylindrical or spherical. It's not that they COULDN'T be other shapes. It's just the cost and structural complexity aren't justified.

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by tree68 on Friday, December 9, 2005 11:05 AM
QUOTE: Originally posted by chad thomas

Or will the cub scouts be subsidizing pressurized Subway sandwiches on Amtrak?[:D]



How about if the Cub Scouts sell the Subway sandwiches on the trains...[:D]

LarryWhistling
Resident Microferroequinologist (at least at my house) 
Everyone goes home; Safety begins with you
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There's one thing about humility - the moment you think you've got it, you've lost it...

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Posted by jeaton on Friday, December 9, 2005 11:08 AM
BEERGIEEEE!!! NOW HARMON IS CHANNELING SEUSS!!!

"We have met the enemy and he is us." Pogo Possum "We have met the anemone... and he is Russ." Bucky Katt "Prediction is very difficult, especially if it's about the future." Niels Bohr, Nobel laureate in physics

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Posted by oltmannd on Friday, December 9, 2005 11:10 AM
QUOTE: Originally posted by Limitedclear

So, does this thread name change indicate that the Cub Scouts will now be serving the Subway sandwiches on Amtrak???

Perhaps we can pressurize a few planes with all this hot air??

How 'bout that Southwest crash at Midway? Ouch. Some bad driving there....

LC


I think it's the Cub Scouts that are pressurized, but I'm no longer sure.

I think that SW flight missed the arresting wire.

Midway is a scary place to fly in and out of in good weather. It's shoehorned into a residential area - a big square with the runways on the diagonals. I think it was built for DC3s with runways just barely long enough for small jets. A few more feet an the plane might have been in someone's living room (non pressurized, of course)

Now, did you know that there were some early attempts to propel subway cars using air pressure (pneumatic tubes)?

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by TomDiehl on Friday, December 9, 2005 11:33 AM
Now THAT'S how to hijack a post.
Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by oltmannd on Friday, December 9, 2005 11:37 AM
Could you pressurize a plane?
Could you pressurize a train?
Have you pressurized my brain?
Or stress relieved this sad refrain?

Subway food just isn't safe.
It makes the union collar chafe.
You need us, 'case the terrorists strafe
and with no job, a homeless waif.

If they serve you at your seat,
They won't ask you "white or wheat"
and they'll have to store it in the heat.
'Coz if it's frozen, that ain't sweet.

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by Mookie on Friday, December 9, 2005 12:44 PM
Dan - since we are hijacking topics - is San Diego still a thrill to fly into? Over the parking garage?

Moo

She who has no signature! cinscocom-tmw

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Posted by dharmon on Friday, December 9, 2005 12:53 PM
QUOTE: Originally posted by Mookie

Dan - since we are hijacking topics - is San Diego still a thrill to fly into? Over the parking garage?

Moo


Yeah baby! Nothing like peeping into the condo bedroom windows on final.......The big thing now is that the county wants the Marines to give up Miramar or allow it for joint civil / military use.....which doesn't work real well. What they proponents won't say is that ..yeah they want the airport, but they really want the upteen thousand acres of undeveloped government property surrounding it....which gives the locals an unrealistic sense of how quiet it is.....to exploit. It's the California way...I'm too stupid to do it right from the beginning..so I'm going to take what someone else has.

I'm beginning to feel a little pressurization in my caboose from the Subway sandwich I just ate....I may need to step outside before Weeblow

Dan

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