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Episode 10: Explosive Decompression, Frog Giggin', Rear Axle

  • A bullet can cause explosive decompression in an airplane: busted
  • A bullet used as a fuse in a truck can fire and injure a person: busted
  • American Graffiti steel cable + police car scene: busted

The coolest segment from this episode was the explosive airplane decompression segment. Jamie and Adam drove out to an airplane graveyard in the Mojave Desert and found an old passenger jet that they sealed up and pressurize. They also placed crash test dummy Buster in a passenger seat at ground zero for their series of experiments: 1) Firing a handgun through the skin of the aircraft. Result: nothing happened. Buster didn't even flinch. 2) Firing a handgun through the window of the aircraft. Result: same as before, nothing happened.

At this point the segment was getting really interesting for me, because it had dispelled my Hollywood-driven belief that a firing a gun on an aircraft would puncture the skin, which would then expand into a large hole, sucking out the evil villain or unidentified extra.

Having demonstrated that the conditions for the myth were false, Jamie and Adam went bigger to try and get the actual result:

3) Blowing out the window of an airplane. Result: Buster's arm was sucked through the opening, and probably would have dismembered a real human being. However, the hole did not expand, and the other passengers probably would have been fine.

4) blowing out a large section of the plane. This was the traditional grand finale where Jamie and Adam go overboard with explosives. The explosive blew out a huge section next to Buster, causing a large roof-section to be torn off as well. It was really awesome. Buster remained seated on the airplane, though he was covered by seats that had been ripped towards the hole.

The other cool segment from this episode tried to replicate the scene from American Graffiti where a steel cable is attached to the rear axle of a police car. The police car takes off to make chase but the cable rips off the rear axle. Jamie actually built a remote control police car to do this. This seems to be a popular project idea for Discovery Channel shows (Junkyard Wars, Monster Garage). Jamie's R/C police car was easily better than the Junkyard Wars cars, which hardly functioned. As for the Monster Garage R/C car, the police car didn't have as big of an engine, nor could it shift gears, but it appeared to not have the steering issues that doomed the Monster Garage car. Then again, the segment focused very little on the actual building/driving of the R/C car.

The last segment was a short one about using a .22 caliber bullet as a automobile fuse. As the story kind of goes, some people were returning on a trip and shorted a fuse. They used a bullet as a fuse and continued driving. Later on, the bullet suddenly fired and hit the driver in a sensitive area. The story, as attributed, was apocryphal, but they discovered that if you do create a short in the electrical system, the bullet will fire. However, due to the housing, it doesn't fire with nearly the same amount of force as it would from a gun (Buster was fine afterwards).

Comments

MYTH BUSTERS ROCKS

send me lots of old milatiry airpaln myths

Explosive decompression is a bit tricky to simulate in that way.
Decompression in flight and on the ground are two separate aspects :

1 - On Ground : incidents have occured where crew have opened an aircraft door before pressure equalisation, with dramatic results. These range from ripped off hands(!) when the door suddenly blows open, to the crew member being litterally sucked out of the aircraft and flying quite some distance, unfortunately with fatal consequences.
Correct, you won't get a shredding effect around the opening in the aircraft, after all, this isn't a balloon ( ever tried pushing a pin into a blown-up balloon ? now put some adhesive tape over a spot and stick the pin through that - no explosion, just a gradual pressure release )

2- In Flight : here you have the added aspect that the aircraft is travelling at approx 800km/h, nothing to be sniffed at. Explosion will not occur, but you will get shredding due to the combination of pressure difference and travelling speed. This has happened quite spectacularly in a number of cases, with entire body sections being ripped off. In some cases, the aircraft can continue to fly ( once a boeing 747 managed to land in Hong-Kong with half the rear top fuselage missing due top a bomb explosion. A lot of the passengers did get torn out of their seats or with their seats, but most of them made it back in one piece and alive).
Working in the aircraft industry, these are facts, not myths, and the manufacturers do everything they can to prevent such destructive failures, and learn from past lessons.
Remember the old Comet jetliner ? it suffered a fatal design flaw (windows in the ceiling without rounded edges) which led to spectacular failures leading to decompression and the loss of a number of machines with all passengers and crew. The result was that these were pulled from service.

The myth from the movie American Grafitti where the diff was ripped out of the police car should have been tested on a car with leaf spring suspension as in the movie not coil spring.

once a boeing 737 ( Aloha Airlines)managed to land in Honolulu with half the top fuselage missing due to a failure of the stucture, the aircraft was not suppose to fly over a certain altitude so the differential pressure will be less than 4 psi all the passengers made it back in one piece and alive).
You will have to check with Aloha airlines
http://www.bootsnall.com/guides/05-09/aloha-airlines-flight-243.html

the police car used had coil springs the one in the movie had leaf springs