MYTHBUSTERS 10th Anniversary Season

[Marc]

I was also disappointed that they didn't try to fire the RPG down and under the front of the SUV as shown in the movie clip.

I'm not sure this would even be possible with an RPG.

We're not talking about guided missile here. Allowing for the basic laws of physics, they basically fly and strike the target at the height it was fired.

to get it go off under the SUV would require it to be pretty much fired at the same height short of firing it angled down to strike the ground just under the front of the vehicle and detonate.

 

[Trekker4747]

Firing the RPG under the car, like shown in the clip, wouldn't have gotten any better or different results. Explosions "don't work like that", in essence. There's been countless times over the years they've tried to make things move by setting up explosions near them and it doesn't happen. Explosions consume things, not move them. Aside from maybe light objects that are probably within the blasting-power of the explosion.

 

[Christopher]

^Even so, it bothers me that they misinterpreted the myth. The clip clearly showed the RPG detonating under the SUV, not going into its front grille. So what they tested was not the myth from the movie. Which makes me wonder about their powers of observation. It's not the first time I've felt the M7 trio has done inadequate work or fallen short of applying due diligence, but this seems even more careless.

 

[Trekker4747]

Eh, I don't think they were trying to replicate that specific scene just the "movie trope" of an RPG exploding causing a heavy vehicle to flip. The clip they used was probably the "best" they could get to demonstrate the idea without resorting to the animations. Afterall, they never mentioned FF6 when setting up the "myth" just mentioned the movie trope of vehicles flipping when hit (or near) an exploding RPG.

But, I agree, there's plenty of times the Jr. team makes little errors like this. I've not watched the Aftershow for the episode maybe their reasoning is addressed there?

 

[Christopher]

^But that leaves an unanswered question for the viewer, namely: Are there any movies that do show an RPG hitting the front of an SUV and making it flip? In my experience, movie and TV scenes built around car-flip stunts usually have the explosion going off underneath the car, not within it, because even movie physics has some logic to it. I've seen one or two cases where an explosion went off under a car and made it flip, and the occupants of the car then climbed out, dazed but alive. (I'd love to see the Mythbusters test that one!) I think there's an example of that in the beginning of Iron Man, though I could be wrong.

So I'm just not convinced that the myth is what they said it was. My impression is that the clip they used (I though it was Fast Five, not 6) was closer to being the rule than the exception.

 

[Mr. Adventure]

If they weren't basing it on that specific clip it seems odd that they would choose shooting it straight in the front from a level position as the ideal way to try to flip the vehicle. Granted physics is not my strong point but I would think hitting it somewhere like a rear quarter panel or wheel would have a better chance.

 

[Christopher]

I'm watching the Science Channel's rerun of Adam & Jamie's Dangerous Toys right now. The sequence of Jamie decapitating those teddy bears to turn them into exploding teddy-bear robots was painful to watch. Who knew he had such evil in him? In the words of Kari Byron, "That is messed up!"

I think the "battle" scenes were somewhat staged, though. Jamie's basketball cannon had only four barrels but apparently fired more than four times (either they repeated things from different angles or they reloaded between shots), and there was no reason why the bears would explode when Adam's spear-arrows hit them.

 

[Trekker4747]

^But that leaves an unanswered question for the viewer, namely: Are there any movies that do show an RPG hitting the front of an SUV and making it flip? In my experience, movie and TV scenes built around car-flip stunts usually have the explosion going off underneath the car, not within it, because even movie physics has some logic to it. I've seen one or two cases where an explosion went off under a car and made it flip, and the occupants of the car then climbed out, dazed but alive. (I'd love to see the Mythbusters test that one!) I think there's an example of that in the beginning of Iron Man, though I could be wrong.

So I'm just not convinced that the myth is what they said it was. My impression is that the clip they used (I though it was Fast Five, not 6) was closer to being the rule than the exception.

Eh, I dunno. It wasn't an "interesting" myth eitherway for me since we've seen enough explosions on this show to know by now nothing was going to happen no matter what. And you're right, it was "Fast Five" the clip was from, not 6.

And I still say they should have tested the vault-hauling scene from Fast Five.

 

[Brent]

The last episode of Mythbusters failed on 2 fronts.

1.) The truck smashing through vehicles. Just go faster. They capped the test at 40MPH. If, in the movies, a bad guy was trying to get through a bunch of cars, he's floor it, going as fast as he could. If they were to have gone 60-70MPH, I bet they would have gone through the whole set of cars with the original bumper. It almost made it through at 40MPH, just a little bit more, it would have gone through.

They failed to even mention the impact that speed makes, and that it is a factor in this. They didn't give ANY reason for only going 40MPH and they did not mention that going faster could make it work. They did not test it. This is a fail in testing, and a fail in explanation.

The way I see it, that whole stunt was just so they could beam a thing on the front of the truck to plow through cars, it was all about that, nothing else. They wanted the result to get to that point to show it off.

2.) The flipping a car with an RPG. Why did the only try it from one angle? They only tried it directly into the radiator. In the movies though, I often see the RPG hitting right underneath the car, from the front, or side. They didn't try aiming the RPG at the ground, and letting the explosion lift the car. This is a viable test to do. They also did not try it from the side of the car, again aiming at the ground, right under the car. This is a complete fail of testing, not thorough enough, and not like the movies.

I see the whole point of that testing just to get to the point of replicating the myth in a "fake" way, with explosions.

Well you know what? If I want to see it done the "fake" way, I'll watch a movie. IMO, when replicating a myth, they should try to get it to happen within the realm of the myth. Perhaps using a more powerful rocket, not an RPG, or those JATO motors they can get, and fire that under the car. Again, all they did at the end was do it the way Hollywood does it, but I can see that in any movie, what I want to see is them try to flip explode the car in the nature of realm of the myth.

So in total, the episode was pretty fail. I think they are getting lazy, and just want to show off explosions and how they build things, instead of really getting at the heart of "myths" and testing them thoroughly.

This is not good, cause I really like Mythbusters, and want to continue liking it.

 

[intrinsical]

This is a heavy industrial truck we're talking about, not a car. These things are designed not designed to go fast. 40-50mph is the typical maximum legal speed limit for these vehicles in most countries. I'm not even certain it can easily reach 60mph without either some serious engine modification or a very long acceleration time.

As for the RPG, they're designed to shred and not push stuff around. The RPG hit straight on at a right angle, which simple physics will tell you is already delivering the maximum possible amount of force. And it didn't even nudge the car. Hitting at an angle, or at the ground simply results in much less push than hitting straight on.

 

[Forbin]

I need that truck for my morning commute!

 

[Christopher]

As for the RPG, they're designed to shred and not push stuff around. The RPG hit straight on at a right angle, which simple physics will tell you is already delivering the maximum possible amount of force. And it didn't even nudge the car. Hitting at an angle, or at the ground simply results in much less push than hitting straight on.

True, but that's exactly why they should've tested it that way. Mythbusters is supposed to be about demonstrating scientific principles. The physics assumption underlying this SUV myth, as well as a lot of other movie myths, is that explosions push things. The premise is that the explosion goes off underneath the truck and propels it into a flip. So they should've tested that in order to demonstrate for the audience that explosions don't push stuff in the way movies show. Sure, some of us already know that, but these tests are for the benefit of those who don't already know that. There's some real physics to be discussed and demonstrated here, and they totally failed to address it because they misdefined the problem. They didn't frame it in terms of a myth about the pushing power of explosions, and thus failed to test that principle.

This myth is crying out for a revisit, but they don't seem to do those much anymore.

 

[intrinsical]

As for the RPG, they're designed to shred and not push stuff around. The RPG hit straight on at a right angle, which simple physics will tell you is already delivering the maximum possible amount of force. And it didn't even nudge the car. Hitting at an angle, or at the ground simply results in much less push than hitting straight on.

True, but that's exactly why they should've tested it that way. Mythbusters is supposed to be about demonstrating scientific principles. The physics assumption underlying this SUV myth, as well as a lot of other movie myths, is that explosions push things. The premise is that the explosion goes off underneath the truck and propels it into a flip. So they should've tested that in order to demonstrate for the audience that explosions don't push stuff in the way movies show. Sure, some of us already know that, but these tests are for the benefit of those who don't already know that. There's some real physics to be discussed and demonstrated here, and they totally failed to address it because they misdefined the problem. They didn't frame it in terms of a myth about the pushing power of explosions, and thus failed to test that principle.

This myth is crying out for a revisit, but they don't seem to do those much anymore.

They have already repeatedly shown explosions do not push. In fact, they did this for another hollywood movie myth "Shock wave surf". My guess is they didn't want another hollywood myth covering the same topic.

I'll agree that they should have at least said something about this before moving on but I do not think a test on an already known fact is necessary.

 

[Christopher]

^But they've done many variants on established physics before. After all, there are only so many laws of physics and they underlie everything.

Remember, not everyone who watches the show is a physics expert, and not everyone who's watching today was watching it in the past. After all, the show is meant to be educational, so there are a lot of young people watching it, kids who may have been too young to be familiar with the earlier episodes. So it makes no sense to say they should never repeat a discussion of a physical principle. Even for those who do watch regularly, it's worth reinforcing the idea that the same physics apply consistently across many situations.


By the way, it occurs to me that the reason so many people believe that explosions push is that sometimes they do push -- they push bullets out of guns and push pistons in a car engine. The difference, of course, is that in those cases the explosion is confined and directed, while the force of an explosion in the open is dispersed in many directions and free to go around a heavy object. That's the principle they should've called attention to. The reason the air ram flips the truck is because all its force is directed one way. Perhaps they could've attempted to achieve the same effect with an RPG or its equivalent, by confining the blast within a heavy pipe under the SUV so that all the force went upward against the underside of the vehicle. That would be replicating the result in a way that still had some relation to the myth, rather than just demonstrating a special-effects technique.

 

[Brent]

This is a heavy industrial truck we're talking about, not a car. These things are designed not designed to go fast. 40-50mph is the typical maximum legal speed limit for these vehicles in most countries. I'm not even certain it can easily reach 60mph without either some serious engine modification or a very long acceleration time.

As for the RPG, they're designed to shred and not push stuff around. The RPG hit straight on at a right angle, which simple physics will tell you is already delivering the maximum possible amount of force. And it didn't even nudge the car. Hitting at an angle, or at the ground simply results in much less push than hitting straight on.

Some trucks have limiters for their speed, but not all, they don't mention if this one does or not. It isn't necessarily illegal for trucks to go faster than this, my dad's Semi truck had a limiter, but it was limited at 60MPH. I bet they could have gotten this truck on the show up to 60MPH. They can't assume we know these things. They are supposed to test it for us, that's the whole point, or at least mention it in commentary The speed issue was never even discussed, other angles from the RPG were never even discussed, let alone tested for our benefit to demonstrate things.

 

[Christopher]

Since they were on the runway at Alameda rather than on city streets, I don't think they had to worry about speed limits. They've done their share of high-speed and otherwise dangerous driving stunts on that runway, and of course it's where the fake freeway of The Matrix Reloaded was built, so it's evidently not a place where vehicles are constrained to follow traffic laws. At least, if one has the proper permits and clearances, I guess.

 

[Forbin]

Somebody had a lotta cleaning up to this week.

 

[Christopher]

Yeah, I do wonder what happens to the remains of all the cars and things they destroy. I hope there's some kind of recycling program in place.

 

[Trekker4747]

I'm guessing there must have been some safety concerns about driving that large truck into the cars at a high speed. That and to echo large trucks like that are either governed or otherwise incapable of going that fast. There may also not have been enough run-up space to get a good speed and still have stopping space afterwards. There's lots of reasons and issues on why they wouldn't or couldn't go that fast on the test.

 

[Christopher]

If the truck had gone faster, there may have been a greater risk of damage to the truck itself, not to mention the Mythbusters inside. Maybe 40 MPH was the most they figured it could withstand without taking serious damage.