MythBusters Episode 10: "Explosive Decompression, Frog Giggin’, Rear Axle"
Air Date: January 18, 2004
Explosive decompression can occur when a bullet is fired through the fuselage of a pressurized airplane, causing the hole to grow dramatically and possibly cause the plane to break up as seen in movies.
busted
The pressure is not high enough and the hole is too small. Explosive decompression only occurred when a hole the size of a window was made with explosives. Even then, the rush of air could not suck Buster completely out of the hole. Lastly, there are proven instances of explosive decompression where the plane was still able to maintain control and land.
(This myth was revisited in episode 38 and it was re-busted.)
A group of hillbillies use a live .22LR cartridge as a makeshift replacement for a burned-out fuse in their truck, but while the truck is driving, the bullet heats up enough to discharge, hitting driver in the groin and causing enough damage to require surgery.
busted*
The bullet did work as a replacement fuse, however when a short circuit was created, the wiring fried and the bullet did not fire. When the wiring was upgraded to a higher gauge, the bullet did fire out of the fusebox, but not with enough velocity to cause any serious injury.
*Though both Adam and Jamie admitted that the myth was plausible from their tests, they had to call it busted due to a lack of conclusive evidence, and the fact that they didn’t have a "plausible" verdict during the first season.
A steel cable, attached to both a street light post and the rear axle of a police car, will be able to yank the rear axle clear out from under the car when it tries to drive off, as seen in American Graffiti.
busted
The rear axle was able to be pulled loose, but only after several bolts securing it were removed. Additionally the axle was caught along the underside of the police car and could not clear the trunk. Adam and Jamie theorized that, in the movie, a ramp was used to give the car and axle enough of a boost to wrench the axle completely free.
Newer: Episode 11: "Sinking Titanic, Goldfish Memory, Trombone Explosion"
Older: Episode 9: "Chicken Gun, Octopus Egg Pregnancy, Killer Washing Machine"
Would the outside pressure of the plane not be the cause for a decompression on the inside.
From my understanding of planes is that the pressure on the inside is set to that of being on the ground, where you can breathe normally. But if you are at a high altitude the pressure on the outside is substantially lower. If you puncture that pressure, because the outside is so much lower and so much more in quantity it would be like a vacuum sucking it out??
If you reversed the scenario thus making the pressure on the inside substantially lower and you fire from the outside - you might have an explosion into the plane - if that makes sense … either that or I’m just not thinking logically and losing my mind.
July 23, 2007 at 9:29 AMPolice Car. It happened some years ago at Tamworth there was a highway patrol office that always was upsetting the locals. They padlocke a chain to a power pole and put a chain arounded the back axle. They also put the chain around over the tail shafte. When the ofice took of in pusuit the back axle was compltely removed from the police car
August 17, 2007 at 3:51 AMPolice car. I’ve never heard of it happening but it may happen with a 1960s period car a late model car has alot more support bars than a 1960s period car which only had leaf springs
August 27, 2007 at 2:37 AMI’m in agreement with Lara. A plane at altitude would have low pressure outside so the outward rush of air would be greater.
September 11, 2007 at 12:25 AMI agree With Laura and Shawn:
The matter is not the outside air speed that makes low pressure. At this altitude (plane cruise) the outside air pressure is already very low (even if the plane isn’t moving).
Their argumentation is deeply wrong.
THIS MYTH ISN’T BUSTED (yet)
September 26, 2007 at 1:28 PMtry harder next time.
I agree with Barry; When I first viewed the episode; I saw the late model car with the locating arms and knew it wouldn’t come free. A basic leaf spring rear suspension would stand a much more realistic chance of ripping out. Needs to be redone.
October 10, 2007 at 11:23 PMPlane:
October 19, 2007 at 2:12 PMI think the myth was not really busted.
In my opinion the speed of the plane causes a much more suction. When you drive your car and open the window, it´s possible that some loose things will flow out of the window…. and a plane is much faster than a plane (and there is the pressure difference)
Rear Axle. I agree a period car should have been used as these have a leaf spring set up which can actually rip out.( I hit a tree stump at about 60KM/hr and tore out the front spring mounting points). The car they useed has what is called a four link setup these are more robust and have stronger mounting points than the leaf setup. Needs to be redone
October 26, 2007 at 12:36 AMIf you watch the episode, they increased the internal pressure of the plane while on the ground to an equivalent internal to external pressure as a plane at altitude. Don’t assume they’d be dumb enough to forget the pressure difference.
December 3, 2007 at 4:30 PMI have been working on cars since 1972. I have seen cars go from points&codensors to distrbutorless sequential port fuel injection systems with anti-lock brakes&front&side airbags. I agree with Grant. The car in the movie was a early 60’s Ford, the car you tested was a late 90’s(or newer)Ford. I say this is like apples&oranges. The older car only had 4 u-bolts &2 shocks holding it, wereas the newer car had a 4-link rear suspension with coil springs & a sway bar & oh yeah 2 shocks holding it in place. I say you need to re-do your test with an older model car that has a leafspring rear suspension to find out if this really did happen in the movie, I think you will find out that it really did happen, because the older suspensions were’nt as stout as the newer ones we have today. Thanks Nutwrench(ASE master auto. tech. since 1981)
December 5, 2007 at 8:19 AMThe decompression myth was busted before it began. The B-24 Liberator was the first Allied military aircraft to benefit from a pressurized cabin. Hundreds of them were damaged by enemy fire, depressurized violently in flight, and survived, 20 years before a movie gave birth to the myth.
January 8, 2008 at 12:31 AMOf course, I believe it is the outside pressure that has an effect on the depressurization, and I believe it is an element that has not been properly investigated on the show. I know how they could test it properly though, email me if you need the details…
January 28, 2008 at 9:21 PMand I think the test they did was not to crash the plane but at least suck out a window9shot out from inside by a bullet) plus a buster or so…
January 28, 2008 at 9:23 PMrear axel, i worked in a suspesion shop for 12 years on everything from cars to cranes i agree with everyone else this one needs to b redone using a period car the one adam and jamie used is a lot newer and stronger lets do it again guys
January 30, 2008 at 12:10 PMThe myth that was busted Re:Rear axel, from the movie American graffiti needs to be revisited because the car used in your show had coil suspension and the police car used in the movie had leaf spring suspension. Cars from the 50s-60s era were made alot simpler. Give it another go guys !
February 27, 2008 at 6:52 AMRedo the american grafiti car stunt with an old school leaf sprung car. IF it got enough velocity it would likely work. It would at least pull apart the drive shaft slip yolk anf likely wrench the axle free, if not tear the spring shackles.
(Journeyman mechanic and wannabe mythbuster)
May 6, 2008 at 1:26 AMPlane: The fact remains that explosive decompression does occur. see: TV series “Mayday”, British Comet, Hawaian Airlines, others. Try explaining the “myth” to the family of the airline attendant or to the pilot that was partially sucked out the window.
July 7, 2008 at 5:16 PMthe explosive decompression can only be proved it the boys get a commercial jet, go to a altitude of 30,000 ft, and shoot out the window. There is no air pressure at that altitude. So if you have pressure on the inside greater to the outside, then you will get a vacuum effect. Remember, a plane pressurized at sea/ground level will not vacuum out. It will just equal out.
September 24, 2008 at 12:22 AM