Mythbusters, I think I just watched them make an illegal machine gun!
- Thread starter Exposure
- Start date
- Status
progunner1957
member
Sorry, no suckage like in "Goldfinger"
I am a "Certificated Airframe and Powerplant Technician" in FAA speak - an A&P mechanic or jet mechanic. I formerly worked for U.S. Air Express and worked on their 50 passenger commuter jets, Embraer 145s.
Every jet has a device called an outflow valve - actually, a pair of them, one for backup. This valve is located in the aft pressure bulkhead; it opens and closes (modulates) to maintain cabin pressure. In the case of the Embraer 145, the hole in the aft pressure bulkhead in which the outflow valve is seated is aprox. 10 inches in diameter. When the valve opens, you have a 10 inch diameter hole in the aft pressure bulkhead. Nothing gets sucked out of this hole except for air.
One of my instructors in A&P school was a flight engineer on a Navy P3 Orion subchaser aircraft. He experienced multiple cabin depressurizations during his career, some caused by "other nations" using his P3 for air to air marksmanship practice. Again, nothing was sucked out except air.
One interesting thing that happens with depressurization caused by a bullet hole or other small hole is that the oxygen molecules exit the pressure hull breach much more quickly than do the water molecules in the air, creating fog in the cabin. That is about as much drama as you get with a hull depressurization, along with the oxygen masks deploying.
No - that's more Hollywood hogwash.
I am a "Certificated Airframe and Powerplant Technician" in FAA speak - an A&P mechanic or jet mechanic. I formerly worked for U.S. Air Express and worked on their 50 passenger commuter jets, Embraer 145s.
Every jet has a device called an outflow valve - actually, a pair of them, one for backup. This valve is located in the aft pressure bulkhead; it opens and closes (modulates) to maintain cabin pressure. In the case of the Embraer 145, the hole in the aft pressure bulkhead in which the outflow valve is seated is aprox. 10 inches in diameter. When the valve opens, you have a 10 inch diameter hole in the aft pressure bulkhead. Nothing gets sucked out of this hole except for air.
One of my instructors in A&P school was a flight engineer on a Navy P3 Orion subchaser aircraft. He experienced multiple cabin depressurizations during his career, some caused by "other nations" using his P3 for air to air marksmanship practice. Again, nothing was sucked out except air.
One interesting thing that happens with depressurization caused by a bullet hole or other small hole is that the oxygen molecules exit the pressure hull breach much more quickly than do the water molecules in the air, creating fog in the cabin. That is about as much drama as you get with a hull depressurization, along with the oxygen masks deploying.
Flyboy
Member
Ahem. Any further discussion of "explosive decompression" and the danger thereof needs to be held in the context of this photo:
The aircraft (Aloha Airlines Flight 243, 28 April 1988--it's a Boeing 737) landed safely, with only one fatality: the stewardess who was standing in the front of the cabin, (obviously) not wearing a seatbelt, who was, in fact, sucked out. Other passengers were injured, but survived.
Find me a gun that can remove an 18-foot long section of the cockpit, and we'll have a legitimate danger. Otherwise, James Bond should stay in Hollywood.
The aircraft (Aloha Airlines Flight 243, 28 April 1988--it's a Boeing 737) landed safely, with only one fatality: the stewardess who was standing in the front of the cabin, (obviously) not wearing a seatbelt, who was, in fact, sucked out. Other passengers were injured, but survived.
Find me a gun that can remove an 18-foot long section of the cockpit, and we'll have a legitimate danger. Otherwise, James Bond should stay in Hollywood.
Attachments
Movie and television studios and production companies are routinely licensed for Class III weapons. In CA they are the only ones who are granted state licenses for full-auto guns so that they can make movies (which usually trash gun rights). So even if they created a machinegun it was probably legal for them to do it.
Father Knows Best
Member
progunner1957 said:
I have to nitpick this statement.
Water molecules leave at the same rate as everything else, including the oxygen and nitrogen molecules that together make up 80+% of the air. What happens is that rapid depressurization causes a decrease in temperature. Think about what happens when a CO2 tank is punctured -- it gets cold due to the dropping pressure. That's also the same way refrigerators and air conditioners work. They compress a gas and then allow it to expand rapidly, causing it to cool. As the air cools, relative humidity rises because cooler air cannot hold as much moisture in gaseous form. This causes the moisture in the cabin air to condense, forming fog.
The same thing happens in air compressors. If you have one, you know it has a drain valve in the bottom, and you need to open it periodically to let the water run out and keep the tank from rusting. The water is there because every time you let air out of the tank the pressure drops and moisture in the air condenses. For the same reason, some air powered tools require driers in line between the compressor and tool to keep excess moisture out of the tool.
I know you didn't really want to know all that, but I have this strange compulsion to explain things scientific even when nobody cares. It's just my lot in life ....
Rosstradamus
Member
jlbraun said:
That contradicts tests the Navy Bureau of Ordnance conducted, as cited in Hatcher's Notebook. Pages 405-408 in my 1966 edition.
molonlabe
Member
I think they said 3 feet of water shot at a 30 degree angle. That transposes to about 6 to 9 feet of water. but OT
Rosstradamus said:
Well, I saw the video. They put the ballistics gel under water only a few feet from the surface. The bullet disintegrated into tiny shreds which slowly fell to the bottom, and the ballistics gel was untouched.
Note that I wouldn't ever try this, but theoretically you're safe behind that little amount of water.
What does the manual say? I'm interested.
twoblink
Member
bogie said:
Jamie is firearms savvy, Adam is.. well, Adam!
I love them! I have every single episode!
Flyboy
Member
...which makes it subject to the very same regulations as a machinegun.
Please pardon my brevity; I was under the impression that the sheer insanity of regulating a piece of string as a automatic weapon would be adequately conveyed without going into extensive technical detail.
Further, given the BATFE's creative license with the idea of "constructive posession," it makes anybody with an AR and a spool of twine a potential felon.
LMAO At this.
There have been several devices over the years that attached to the trigger and via a crank, would depress the trigger thus firing the weapon.
These have all been determined as to the best of my knowledge to be classified as a nothing. You have not altered the firearm to cause more than one shot to be fired at a time with a single depressing of the trigger.
You are simply pulling the trigger faster.
Been in the business a good many yrs with my own Class III toys.
But it has been fun reading the opinions an entertaining as well.
5.56
There have been several devices over the years that attached to the trigger and via a crank, would depress the trigger thus firing the weapon.
These have all been determined as to the best of my knowledge to be classified as a nothing. You have not altered the firearm to cause more than one shot to be fired at a time with a single depressing of the trigger.
You are simply pulling the trigger faster.
Been in the business a good many yrs with my own Class III toys.
But it has been fun reading the opinions an entertaining as well.
5.56
Exposure
Member
You have been in the businees "a good many yrs." and you still think electric driven crank triggers are legal?
Here is an excerpt from a letter written by Edward M. Owen, then Chief of the tech branch at BATF .
"using an electric motor to fire the weapon instead of hand cranking, would
be classified as a "firearm" and a "machinegun" as defined in Title
26 U.S.C., Chapter 53, section 5845(b), the NFA.
Electrically driven machineguns such as the M-134 Minigun are
firearms and machineguns subject to the provisions of the NFA."
Therefore yes, hand cranks are legal. Electrically driven cranks are not.
Might want to get your facts straight before laughing your a$$ off and commenting on the "entertaining" opinions given here at THR.
Last edited:
- Status
