Jamie and Adam were to build gliders made from concrete. Jamie’s was clearly superiour, but crashed and burned. However, I was bugged by the way they released them. They determined “glide ratio” would determine the winner.
Adam rigged up some guide-wire thing with a pulley, and Jamie just threw his off the balcony. If they both had the guide wire thing, or both just tossed them, I’d think Jamie’s would have prevailed.
Of course shooting them out of a cannon would probably beat both of them. Yeah, I’m lame.
I agree that they should have decided on a launch method and used it for both gliders. But Adam’s glider did land flat, while Jamie’s emulated a lawn dart. So I’d say that Jamie did not calculate the cg correctly and his glider was nose-heavy.
They’ve also said on previous episodes that they film many more tests for each experiment, but of course a lot of their footage ends up on the cutting room floor. (In fact, I’ve seen at least one episode that was nothing but outtakes, showing tests that didn’t make it to the final cut.) So it’s possible, I guess, that those two methods were just considered to be the best way to show their findings. They do also respond to viewer questions/complaints if they get enough outcry over a particular experiment, so you could write and see if a future episode shows a “OK, so this is what you didn’t see about the concrete glider testing” segment, or a re-test.
Sticking that three foot rod out the front was wierd. I’m wondering if he misunderstood the Nasa guy or something, cause that pretty clearly threw off the COB.
I don’t think it was weird, per se. But it did seem too long before he launched. I would have added clay to the nose instead of a stick. And I would have done some testing first. For example, by tying a line to it and swining it to see if it was behaving as expected.
Jamie did great work keeping the weight low, but I was worried about the stability. At first, it looked to have horizontal stabilizers but no vertical. Later, I think they were canted up into a V-tail, but they were still wobbling on the wires they were mounted on. If it hadn’t nosed over, I think one wing would have lifted more than the other and it would have rolled in.
On something as specialized as this, I wish they’d have gotten more outside help. I love this show, but if Jamie and Adam can’t become master aeronautical engineers in three days that doesn’t mean a myth is busted. Let the NASA guy build a glider, too; I’d have loved to see what he came up with.
The problem I saw was that they were tossing the term “Glide ratio” around as if it were some important and meaningful constant, when in fact it is (as measured) totally dependent on speed-at-release.
Jaime’s, if you watch closely on the rapid descent, flipped upside down and came back about a foot.
I think the way Adam launched his made more sense. Considering it was a glider, it makes sense to give it a chance to get up to speed and stabilize before the actual ‘launch’.
Exactly what I yelled at the TV. I’m pretty sure that if I tied a brick to that line and released it after it gained speed, it would travel some short distance instead of going straight down. Just like the glider did.
That didn’t prove anything about his plane’s ability to glide, and all the mumbo jumbo about glide ratios sounded like he was just trying to make the data come to some good result.
Both gliders should have been launched in the same manner (preferably the way Adam did it), with about the same speed at release. Adam’s glider, as mentioned in the episode narration, had a weighted gondola added that tended to stabilize it in pitch. It flew, well, like a concrete glider, but remained level and therefore managed to achieve some distance due to its forward velocity
Jamie should have carried out more rigorous pre-flight testing to determine the correct balance and trim for his glider. Had he done so, and had he launched off the same guide wire, I’m fairly certain he would have won easily.
Glide ratio, more commonly known as L/D (lift/drag) does NOT depend on weight. Weight determines at what speed best L/D occurs at. Competitive sailplanes racing in strong conditions carry water ballast to increase thier speed. The added weight does reduce the climb rate in thermals however.
A very heavy glider NEEDS to be launched at high speed in order to be able to generate sufficient lift to support itself. A ballasted racing sailplane would need to be towed at perhaps 65-70 kt. while a lightweight training glider would be fine at 45-50 kt. Yet the racing glider can have a L/D > 40:1, while the trainer is in the low 20s.
Disclaimer: My comments are based soley on the content of this thread. I don’t have access to cable TV, so have never seen the show or series under discussion.
I don’t know diddly about glide ratios and such, but at a minimum, shouldn’t they have launched their models in the same way? One was launched on a system designed to maximize its ability to glide, and the other was just flung off a platform with no method at all.
That seems unlike the Mythbusters to do all that work building the models and then completely ignore how they would make the two tests comparable and measure the results. They looked like a couple kids throwing their models off the roof and saying “mine went farther!” Their results involved about as much science as that.
The concrete glider was pretty weak stuff. I expect it to be revisited. The cynic in me says they wanted it that way.
Anyway, having the winning glider be based on a 19th Century design seems a bit iffy. And Jamie’s just seemed like some randomly made paper airplane.
I think they should have paid more attention on how to strengthen the concrete (probably through some sort of light plastic rebar), as well on how a 20th Century engineer would design a glider.
Jamie just seemed disgusted with the whole thing by the time the launch came. He really seemed put off buy the “build off” aspect.
I have launched enough paper airplanes in my time to know that when you have a nose dive like that, it either needs more weight at the back or less in front. Since no mention was made of this, and no attempt was made to launch them in an equal manner, I wonder if Jamie had by that time just decided that he had already wasted too much time, and wanted to toss his glider away and go home.
I just have to throw this in whenever the Mythbusters come up: Not one person involved in the show is a scientist. They are actors and model makers, and very often their science is really, really bad.