Mythbusters: Giant Slingshot Episode

[Cyrus]

first they try to recreate the myth

Yeah exactly. So you tell me, if they can’t reproduce it time and time again, but 'in theory' it should be able to be done, how is that achieving the myth, gimme a breakkkkkkkkkkk.

 

[tribdog]

Yah but when they do it "by any means possible", that means the myth isn't correct!

and those myths are busted. but there are a couple that I don't think they busted, they simply showed they couldn't do them. Their experiments were flawed or they didn't explore all the possibilities.

 

[Cyrus]

http://video.search.yahoo.com/video/view?&h=240&w=320&type=msmedia&rurl=www.eng.uah.edu%2F%7Efrederic%2FBuffer&vurl=www.eng.uah.edu%2F%7Efrederic%2FBuffer%2Fbottle%2520rocket.wmv&back=p%3Dbottle%2Brocket%26ei%3DUTF-8%26fr%3Dslv1-&turl=re2.mm-so.yimg.com%2Fimage%2F1849296965&name=<b>bottle%20rocket</b>.wmv&no=1&tt=143&p=bottle+rocket&size=1.9MB&dur=68"


that looks fake as hell if you ask me.

 

[TheStatutoryApe]

http://video.search.yahoo.com/video/view?&h=240&w=320&type=msmedia&rurl=www.eng.uah.edu%2F%7Efrederic%2FBuffer&vurl=www.eng.uah.edu%2F%7Efrederic%2FBuffer%2Fbottle%2520rocket.wmv&back=p%3Dbottle%2Brocket%26ei%3DUTF-8%26fr%3Dslv1-&turl=re2.mm-so.yimg.com%2Fimage%2F1849296965&name=<b>bottle%20rocket</b>.wmv&no=1&tt=143&p=bottle+rocket&size=1.9MB&dur=68
that looks fake as hell if you ask me.

Sorry it was hurting my eyes.

 

[tribdog]

That's not true at all.

myths like the ones on the show where they can come up with experiments to prove or disprove them have some possiblity to them or what's the point of setting up an experiment. The ones that are flat out impossible wouldn't become wide spread. There has to be a kernal of truth or possible truth in them

 

[Pengwuino]

and those myths are busted. but there are a couple that I don't think they busted, they simply showed they couldn't do them. Their experiments were flawed or they didn't explore all the possibilities.

Well you need to realize that they DO do the experiments very thoroughly, it's just that you never get to see most of it. If you've ever seen like... dvd versions, on-demand discovery channel versions, and ESPECIALLY the re-visits, you'll realize that they do a lot of work on each myth and do try to approach in many different ways and do the experiments as best as possible.

 

[tribdog]

jesus christ okay. mythbusters are gods. I don't know what I was thinking. it is safe to pee on third rails and it is impossible to make a rocket using compressed liquid as the propellant. what was I thinking. you all win. you are all such smart people you know that there is no difference between difficult and impossible.

 

[Cyrus]

Well, I am glad were all in agree ment here.

 

[TheStatutoryApe]

YAY! I'm going to go pee on the third rail now!

 

[tribdog]

can't say I'm nonconformist

 

[tribdog]

you late night people are too confrontational for me. I'm going to bed

 

[Cyrus]

I will haunt you in your dreams MUAHHAHAHH!

 

[tribdog]

probably, but I'll hunt you down and kick your butt in real life

 

[Cyrus]

Bring it on old man!

 

[tribdog]

make up your mind, old man or woman?

 

[Cyrus]

Old Trany!

 

[DaveC426913]

I've had the same discussion in my house. What IS the philosphy of the show?

Some things to consider:

1] Myth vs. urban legend?
Myth = something seemingly common sense, no claim it ever really happened
Urban legend = the claim that some event actually happened and we're just trying to see if it is plausibly possible

2] Myth "as-told"
"if we change this or that, it will work"
"this is what has been claimed". Any change to it means is not the same myth (or more accurately, not as the urban legend claims it happened)

3] Theoretical vs. practical?
Can something be done in any *practical* way? Is something at least *theoretically* possible?

4] HOW busted is it?
If a zippo lighter won't do the deed, will a flamethrower?

 

[zoobyshoe]

I've seen at least two episodes where they didn't bust the myth, but claimed they had. One was when they tried to electrostatically charge a large piece of PVC pipe with a sandblaster. In the myth, this happened outside. In the recreation they did it in an enclosed space where a huge cloud of sand dust built up. Outside the sand would have been carried away by the breeze. Inside it was in constant contact with the pipe keeping it grounded to everything around -no way it could build up a charge.

In the other one they tried to split an arrow in a target from nock to tip with another arrow. They couldn't do it and declared the myth busted. They idiotically only used arrows and arrow substitutues that did not have grain that lead from the nock to the tip. Arrows made from natural materials like tree shoots or small branches of many kinds have uniform grain that can be split pretty much in half their whole length. Alot of arrows are made of reeds and cane, as well, both of which could be split from nock to tip. Instead, they consistantly used arrows and dowels milled down from larger stock whose length dimension didn't follow the grain of the wood. It's no wonder they couldn't split them in half. At no point though, did they even consider they might not be using the right shaft material, and never researched how pre-mass produced arrows were made.

 

[Moonbear]

I've had the same discussion in my house. What IS the philosphy of the show?

Entertainment and/or ratings. It seems to me if they wanted to more seriously bust myths than just provide entertaining stunts for the viewers, they'd be consulting experts on each project. With zooby's example, they should have consulted an archer, or even someone who sells arrows, about the choices of material available for both shaft and arrowhead. You're not going to use the same types of arrow to show off tricks on a target as you'll use to go deer hunting or for a novice to practice with.

 

[BobG]

http://video.search.yahoo.com/video/view?&h=240&w=320&type=msmedia&rurl=www.eng.uah.edu%2F%7Efrederic%2FBuffer&vurl=www.eng.uah.edu%2F%7Efrederic%2FBuffer%2Fbottle%2520rocket.wmv&back=p%3Dbottle%2Brocket%26ei%3DUTF-8%26fr%3Dslv1-&turl=re2.mm-so.yimg.com%2Fimage%2F1849296965&name=<b>bottle%20rocket</b>.wmv&no=1&tt=143&p=bottle+rocket&size=1.9MB&dur=68"
that looks fake as hell if you ask me.

Definitely.

Here's the problem with the experiment, as they did it. They have no attitude control. The thrust from each bottle should come pretty much straight out of the bottle. Any imbalance in the thrust will mean one side of the rocket will accelerate at a greater rate than the other - in other words, the imbalance induces a torque which causes the object to start spinning. As soon as the object starts spinning, none of the bottles are providing a force in the proper direction. Which is why you would expect the mannequin to routinely do face plants (the center of mass is always below the line of thrust since the bottles are strapped to the man's back)

The video shows the bottles did produce a torque which starts to rotate the man, but the off-line thrust doesn't affect his trajectory. Additionally, his pitch goes bad right off the bat, but instead of continuing to pitch end over end, his pitch more or less restores itself. The yaw acts the way you would expect - once you've started rotation about the yaw, there's nothing to slow it down.

The trajectory violates the laws of motion. The guy should experience a constant acceleration towards the ground. Instead the guy appears to experience a constant velocity towards the ground. He almost appears to float, but I think that's an optical illusion based on what we expect his trajectory to be.

First of all, the bottles need to be as close as possible to providing thrust in alignment with the center of mass. Instead of strapping many bottles to his back, a few bottles with very high pressure need to be strapped between his legs. A feedback system needs to be designed so the amount of thrust from one bottle controls how "open" the opposite bottle is. That way, if one bottle is providing more thrust than it's opposite counterpart, it's thrust provides a larger opening in the opposite bottle than the opposite bottle provides for it - imbalances become self correcting before the torques build up.

Edit: Actually, mounting the bottles on a cross frame and duct taping the man's hands to the frame and allowing him to trail the bottles will be a more stable configuration. A four fin configuration can be strapped around his bound ankles. Since the feedback system will require thrust from the opposite bottle to control the opening of each bottle, when there is no more thrust, all the bottles will remain closed, providing bouyancy once the man lands. Then he can be retrieved by boat and untied.

 

[Cyrus]

Then he can be retrieved by boat and untied.

If he does not drown first.

 

[moose]

Sometimes they try to test something to see if it has ever happened and they call it busted. Yet, sometimes, under perfect conditions, it would occur as myth says. It wouldn't be "practical" or happen all the time, but it is still possible... That is what I don't like about some as well...

 

[FredGarvin]

Oh my god. That water rocket clip was awesome! I am really laughing out loud.

 

[DaveC426913]

Entertainment and/or ratings.

Uh, well, yes. I mean secondary to that.

I'll modify the ? to say: how do they rationalize what they're doing?

 

[franznietzsche]

you want examples:
off the top of my head they say you can't die by peeing on the third rail. I've peed on an electric fence and got shocked so I know they are wrong

No, they said you could. They proved that one. What they said is that you'd either have to be real close or peeing real hard to get solid stream from your body part to the rail, making it unlikely, but their dummy got zapped when they messed with the setup enough.

the water bottle rockets obviously have enough power, they just couldn't get them all to fire at the same time so they said it couldn't be done.

Haven't seen that one.

 

[Pengwuino]

oh my god Jamie just said "Amperage" on mythbusters :O :O :O

 

[FredGarvin]

Uh, well, yes. I mean secondary to that.
I'll modify the ? to say: how do they rationalize what they're doing?

Coming from someone who has to endure the countless of idiotic e-mails my mother insists on forwarding me...I would hope there is a core belief in that show's producers to hopefully educate part of the populace out there enough to realize that 99% of the stuff they see out there is BS.