DB Cooper

[Hominid 0]

Quote

You do realise the pressure issues have not been
resolved - I sit and wait for some genius to do it -
Far-a-flung .... and No, I did not bring Hominid here?
(How would I and when?)

Long ago I brought Bernoulli up but 377 and Ckret
said no, so I abandoned that idea. Still something
accounts for the pressure differential when doors are
opened and closed etc in an 'unpressurised' cabin.

Lets see: pressure inside and outside the vessel the
same (at 10,000ft), traveling at 170 kts, must be
some kind of ram pressure involved, laminar flow
across the skin of that vessel, vacuum at certain
locations along the vessel (especially near the back
and underside back?), ..........

Sorry, Georger. No I didn't realize pressure issues remained. I thought you just accepted me saying that the pressure inside the plane was essentially just the outside air pressure. That is, "static" or still-air pressure. You mentioned ram pressure and airstream flow at the rear, so I'll address them.

First, if the plane had a big hole in the nose as it flew along, this would be a path for air to be rammed into the plane as a result of the plane flying through the air. Assuming the rest of the plane was closed off, this would raise the pressure inside the plane. The whole plane would be acting like a big pitot tube facing into the airflow.

That does not apply to the hijack situation because there wasn't that big hole up front. So, neither does ram air pressure.

The airstair hanging down in back would be the main cause of pressure drop when the stairs dropped. If it were just the open hole back at the airstairs the air flow would be almost parallel to the hole opening.
At the speed of the plane (well subsonic), and because of the streamlining of the aft end of the plane, the pressure drop produced would be very small compared to the static pressure. The aft end of the plane is sort of a flattened cone. The airflow would very closely follow the contour of the fuselage. The pressure drop would be most like the pressure drop caused by air passing by the static pressure pitots on the plane. Essentially zero drop.

When you drop the stairs, the stairs project out into the airflow. A vacuum is created on the downstream side. It's like, when driving a station wagon with the near-vertical rear end, a vacuum is created behind the car. And a semi rig going down the hiway makes a big vacuum behind the trailer.

Still the vacuum caused by dropping the stairs is not very large, for two reasons: the stairs are sloped (not perpendicular to the air flow); and the frontal surface of the stair is rounded. And the vacuum immediately aft of the stairs does not just travel up to the cockpit. In the flight test, dropping the stair produced a little drop seen on instrumentation but not big enough that occupants noticed it.

Speak up if you need more. I know R99 can answer such questions if he wants to.

[Farflung 0]

Case in point 377.

Hominid is a world class BS-er to try and fly a 20 atmosphere pressurization system off on this thread. He thinks that everyone is as shallow as georger and just as technically inept. Notice the silence from the Glimmer Twins?

Shame on them BOTH! SHAME!!! Do these senior citizens with marginal control of their bowels know the depths of their depravity? Clearly the answer is no and they don’t care to learn.

[Farflung 0]

Hello Hominid

Chantilly lace had a ……

[Farflung 0]

Have you heard?

http://www.youtube.com/watch?v=VBmhA6z6ieY

[Hominid 0]

Quote

I merely replied to a Hominid geek in geek terms. You invented the rest. Your problem with perfection is your own. Get a channeled reading from Vicky or JT?

I'm sorry, Georger. I don't want this to bother you, so I'll explain how someone can go back and pick out a thing or two from the past to support any idiot viewpoint.

ALL,

377 never invited me to dropzone. Shortly before I arrived I was watching the goings on relative to the analysis I had done and 377 had posted here. I noticed that PEK771 said something like it was interesting. I noticed that Georger said something somewhat complimentary about the analysis, mentioned that I might even be reading the goings on, and he said something like he hoped I would post something or answer questions or something. It was just an off-hand invitation. Although the post was under "naturehominid," Georger just referred to me as "Hominid." That's easier, so I just used that when I signed up. And I mentioned that when I thanked him for his earlier gracious comment. Why does this have to be explained as though it were something evil?

[Farflung 0]

Hey Hominid….

Lemme translate for those who don’t speak BS……

[Farflung 0]

Hey Hominid….

Would it be OK, if I may, if it isn’t too much of a bother. Because you are so honest and forthright, could I; like georger (who is so cool), quote a few of your sentences from your previous posts (which are so great)? Please say yes, all spontaneously and gee I’d sure like to wash your hair some day-y. That would give me a raging ‘diamond cutter’ if you would because you are so strong and cool.

http://www.youtube.com/watch?v=JchKa8Ox3Hs

Would you like some tea Homi-prissy-pants?

[Farflung 0]

Let’s all say ‘so long’ to someone’s credibility …..

http://www.youtube.com/watch?v=TjHJ_snG3RI

Not exactly a shock since he has consistently conducted himself like a troglodyte for years and years.

Let’s try and find something positive from such a reprehensible and repugnant person. Forgive those who trespass…. How generous for georger. The world is kinder without him. Otherwise he would have been more generous and less douchey.

Let’s all speak un-ill of the last remnants of georger’s credibility while he acts like he is utterly surprised by this announcement. He is consistent if nothing else (like honest, attractive, smart, fresh smelling).

[Robert99 50]

Quote

Quote

You do realise the pressure issues have not been
resolved - I sit and wait for some genius to do it -
Far-a-flung .... and No, I did not bring Hominid here?
(How would I and when?)

Long ago I brought Bernoulli up but 377 and Ckret
said no, so I abandoned that idea. Still something
accounts for the pressure differential when doors are
opened and closed etc in an 'unpressurised' cabin.

Lets see: pressure inside and outside the vessel the
same (at 10,000ft), traveling at 170 kts, must be
some kind of ram pressure involved, laminar flow
across the skin of that vessel, vacuum at certain
locations along the vessel (especially near the back
and underside back?), ..........

Sorry, Georger. No I didn't realize pressure issues remained. I thought you just accepted me saying that the pressure inside the plane was essentially just the outside air pressure. That is, "static" or still-air pressure. You mentioned ram pressure and airstream flow at the rear, so I'll address them.

First, if the plane had a big hole in the nose as it flew along, this would be a path for air to be rammed into the plane as a result of the plane flying through the air. Assuming the rest of the plane was closed off, this would raise the pressure inside the plane. The whole plane would be acting like a big pitot tube facing into the airflow.

That does not apply to the hijack situation because there wasn't that big hole up front. So, neither does ram air pressure.

The airstair hanging down in back would be the main cause of pressure drop when the stairs dropped. If it were just the open hole back at the airstairs the air flow would be almost parallel to the hole opening.
At the speed of the plane (well subsonic), and because of the streamlining of the aft end of the plane, the pressure drop produced would be very small compared to the static pressure. The aft end of the plane is sort of a flattened cone. The airflow would very closely follow the contour of the fuselage. The pressure drop would be most like the pressure drop caused by air passing by the static pressure pitots on the plane. Essentially zero drop.

When you drop the stairs, the stairs project out into the airflow. A vacuum is created on the downstream side. It's like, when driving a station wagon with the near-vertical rear end, a vacuum is created behind the car. And a semi rig going down the hiway makes a big vacuum behind the trailer.

Still the vacuum caused by dropping the stairs is not very large, for two reasons: the stairs are sloped (not perpendicular to the air flow); and the frontal surface of the stair is rounded. And the vacuum immediately aft of the stairs does not just travel up to the cockpit. In the flight test, dropping the stair produced a little drop seen on instrumentation but not big enough that occupants noticed it.

Speak up if you need more. I know R99 can answer such questions if he wants to.

Hominid, A few comments. Instead of the term "vacuum", I would use "reduced pressure" since there is not going to be a "vacuum" adjacent to an aircraft in the altitude and speed range that we are discusssing.

"Total Pressure" exists at a "stagnation point" on the leading edge of a wing, the vertical and horizontail stabilizers, or somewhere on the nose cone of the aircraft. I personally would distinguish between "stagnation points" and simple "dead air" points. A few eons ago, when flying my little Cessna in a very light rain, a "dead air" area would become visible when raindrops would actually stop in a very small area on the centerline of the windshield adjacent to the engine cowling. This area was only about 10 square inches but the airstream sweep the rest of the windshield clear of raindrops. [While this area may technically have been a "stagnation point", I would still prefer to call it "dead air".]

"Static pressure" is the pressure perpendicular to the free airstream velocity vectors. In the simplest versions, static pressure and total pressure are measured on the same pitot-static probe. But for various reasons these pressures may be measured at widely different points on an aircraft. In the higher performing aircraft, a great deal of work goes into doing everything possible to minimize, and hopefully completely eliminate, the "position error" for the static and total pressure probes.

By the time the airflow gets to the rear of the aircraft, the layer of air immediately adjacent to the structure has transitioned from a "laminar" to a "turbulent" boundary layer. This change is what puts the dust on the rear window of your station wagon when you drive down a dirt road. You can see the same process behind cars when driving down the highway when it is raining.

The static pressure in this "dead air" region is about the same as the pressure would be in the station wagon if the rear window was partially open. But a few more feet behind these vehicles the free stream air would be moving in, the local air situation would be mixing things up, and the atmosphere would be returning to a normal situation.

[georger 244]

Quote

Geoger : Please allow me to brush up on my reading techniques before you send any buisness my way. Im still trying to master spelling and keyboards. Is Chanelling that thing you do with a remote control the same unit that turns things Off and On? Hmmm!!!!! Jerry

No problem.

If you dont know about "spirit channeling" then you
havent missed anything.

Better I had never brought up.

[JerryThomas 0]

Geoger: As you may espect. Damned I forgot what I was going to say. I guess its my turn turn read the instructions on how to operate a remote controll. Jerry

[georger 244]

Why does this have to be explained as though it were something evil?

[Farflung 0]

Hey georger!!!!


http://www.youtube.com/watch?v=BGLR25EJtfE

Did you consider bringing this up??????

Don’t worry you come across as cool and not like a loser!!!! (not a loser)

Stay classy!!!!!! Please say yes.

[JerryThomas 0]

Farflung: Enough one simple word. Enough point made Check mate. Jerry

[georger 244]

By the time the airflow gets to the rear of the aircraft, the layer of air immediately adjacent to the structure has transitioned from a "laminar" to a "turbulent" boundary layer. This change is what puts the dust on the rear window of your station wagon when you drive down a dirt road. You can see the same process behind cars when driving down the highway when it is raining.

The static pressure in this "dead air" region is about the same as the pressure would be in the station wagon if the rear window was partially open. But a few more feet behind these vehicles the free stream air would be moving in, the local air situation would be mixing things up, and the atmosphere would be returning to a normal situation.

[Farflung 0]

Wrong AGAIN georger, that was Hominid that made that stupefying statement that you find charming. Perhaps this will refresh your memory.

If you need to see it again just say the word. Stay classy!!!!

[Farflung 0]

Really Jerry??? I didn't see ANY contrition. Perhaps you could direct me to a source?

[Farflung 0]

Why are you defending someone that was caught telling bigger lies than you have constantly accused others of making (read Jo)?

Sorry, but honor is a one way street in my world and you better learn the traffic patterns. Don’t come in charging others with lying or missing a polygraph then say that enough is enough when someone (your pet) gets caught doing just as bad or worse. Capiche?

There is a big old world out there and it isn’t as stupid as some may want or hope to believe.

Last word ever on this subject.

[JerryThomas 0]

Farflung: You and Geoger Both proved your points. Still it is obvious that the bone you pick has enough meat on it for all. Point being you both have made your points . Now the public can decide. Jerry PS and the winner is ( maybe it can be [posted on hominids web site Yahoo something or other. ) whats that web site again. Jerry

[Robert99 50]

Quote

By the time the airflow gets to the rear of the aircraft, the layer of air immediately adjacent to the structure has transitioned from a "laminar" to a "turbulent" boundary layer. This change is what puts the dust on the rear window of your station wagon when you drive down a dirt road. You can see the same process behind cars when driving down the highway when it is raining.

The static pressure in this "dead air" region is about the same as the pressure would be in the station wagon if the rear window was partially open. But a few more feet behind these vehicles the free stream air would be moving in, the local air situation would be mixing things up, and the atmosphere would be returning to a normal situation.

and to add: was not the rear door cracked (partially
open) upon tackoff from SEA, as per Cooper's
request. Stairs not out/down but rear door cracked. ?

Once the rear door is opened (fully) then what
happens to the pressure inside the cabin?

Are we correct in assuming the area immediately
behind the aircraft is a low pressure area - lower than
inside the cabin?

[JerryThomas 0]

Farflung: All I am doing is what you have done in the past . maybe some of what you have said in the past soaked in or who knows. Still Both of you are on the borderline, Take it to The PM side of this thread. It could be a better end result. Jerry

[Farflung 0]

You’re right…. Duane Weber was DB Cooper.

[JerryThomas 0]

Farflung: Do yoyu realy think I was not prepaired for that comment. I am suprised it came from you. My put downs on this forum are to those who make false claims. Not to those that argue certain points. Any one that claims that a airline pilot could have been Cooper has a serious problem with reality. Any one that claims that a person with the qalifications as galen Cooks Suspect has a problem understanding People. Still there are others that make up stories just to sell books and make Money. Then there are the fraudes or Scam artists these are the ones I expose. Now your comment was made out of anger and not that of the adult you have portrayed youself to be!. Attacking me is the wrong thing to do . I took sides with no one. Jerry

[georger 244]

Quote

Quote

By the time the airflow gets to the rear of the aircraft, the layer of air immediately adjacent to the structure has transitioned from a "laminar" to a "turbulent" boundary layer. This change is what puts the dust on the rear window of your station wagon when you drive down a dirt road. You can see the same process behind cars when driving down the highway when it is raining.

The static pressure in this "dead air" region is about the same as the pressure would be in the station wagon if the rear window was partially open. But a few more feet behind these vehicles the free stream air would be moving in, the local air situation would be mixing things up, and the atmosphere would be returning to a normal situation.

and to add: was not the rear door cracked (partially
open) upon tackoff from SEA, as per Cooper's
request. Stairs not out/down but rear door cracked. ?

Once the rear door is opened (fully) then what
happens to the pressure inside the cabin?

Are we correct in assuming the area immediately
behind the aircraft is a low pressure area - lower than
inside the cabin?

Georger, With the stairs closed and the rear door to the pressure hull open, the cabin pressure would be essentially the same as the free stream static pressure as the aircraft climbed to 10,000 feet. That is, the "cabin altitude" will be essentially what is shown on the pilot's altimeter.

When the stairs are lowered, the disturbances in the air flow will cause some slight change to the static pressure in the cabin but it will be essentially the same, if not exactly the same, as the static pressure in the "dead air" area.

Nature abhors a vacuum and the cabin pressure will attempt to equalize with any other pressure that it is exposed to.

[ClassClown 0]

Quote

Why are you defending someone that was caught telling bigger lies than you have constantly accused others of making (read Jo)?

Sorry, but honor is a one way street in my world and you better learn the traffic patterns. Don’t come in charging others with lying or missing a polygraph then say that enough is enough when someone (your pet) gets caught doing just as bad or worse. Capiche?




There is a big old world out there and it isn’t as stupid as some may want or hope to believe.

Last word ever on this subject.

Farflung with a left hook to the chin of Jerry Thomas.......and down goes Thomas, down goes Thomas