Hi, everyone. My name is Gus Posey. I'm the STEAM lead here at Wings Over the
Rockies Air and Space Museum. Today, I'm going to teach you a fun paper airplane
called the Cobra. Also pronounced the Cobra. And, as you're going through these
folds, I hope you have a good time with that, but I also want to stress this is a
plane that will really benefit from a nice symmetrical fold. So, as much as we
can keep that the same on one side as the other, the better this will fly.
At the end, I'll also teach you the secret launch technique for the Cobra, and I
think you'll have a lot of fun with that as well. As I often do, I'm going to start
with the 8.5 by 11 sheet here with my logo in the bottom
right corner, facing downwards, towards me. That'll put it on the wing, when we're
done folding. Now, the first fold here is going to be important, because I do want
this to be symmetrical. So I'm folding this across, as we so often do. The hot
dog bun fold. Just matching the corners carefully at the bottom and the top to
make sure they're actually the same. Perfection is elusive, but we do want to
see, if we can get as close as possible for the Cobra folds. Now, when I open this
up, we have a reference line here in the middle that will serve us well, as it so
often does. We take the top edge and the corner and just fold it right on to that
center line. It's important that I don't leave any space at the top. I want to
make sure these triangles are the same on both sides. So, one fold there and, as
this one comes across here, it's coming right down to that same edge, just like
that. So, again, kind of a traditional fold, that basic house shape to get us started.
Now, at the top of the triangle, we are going to fold this down but not very far,
just to the intersection of our center line and the bottom of our folded
triangles. So it's just coming down here, just a little bit, to match that edge.
Now, if you've done some origami or some other folding, you may know what's coming here.
But we need to reverse this to make it work a little bit better. So, right
here at the top of the program, we have kind of a tricky step. I'm going to open
up my triangle here. I'm going to open up my triangle here and here, just to see
my lines. And, hopefully, you can see on your video, here, my triangle is still
there in my creases. Right there at the top of the page.
Now, here's what that's going to look like. I need to fold this back down here, so the
point of the triangle is touching the center line. And now I'm going to reverse
these folds. So, using my fingernail, I'm just giving it a little bit of a scratch
here, a little bit of a scratch here, and that allows me to do this. The line is
now pretty flat against the paper, so I can go from the center to the next
corner and fold the next corner right to the top of the page. Now, half
the triangle is on the bottom, from the center to the next corner I can fold
that to the top of the page, as well. And now, the triangle which was on the top is
on the bottom, giving us a shape like this.
Once again, grab your marker, just giving me a little extra chance to flatten
these out. A nice sharp crease is always helpful. Now, with a shape like this, we're
going to go right to the top of the fold here and fold it straight down. Looks a
little bit like an envelope. Something kind of like that. Make sure I have a
nice flat edge across that top surface, going right out to the corners. Now, if
you have a shape like this, you're in good shape for the next fold. The corner
here folds from the edge out to that same intersection, so where the center
line just goes right to the edge of that folded shape. If you want to make sure
this is nice and flat, again a flattening tool of some kind is a great
idea. And, of course, I'll do that on one side and the other ones just match.
You put those corners together in the center line. Makes the same space at the top and
a very symmetrical pair of wings. As I did before, I'm just going to give this a
little extra crease here, a little extra crease here and believe it or not, we're
almost done. Now, with these in place, we have the beginnings of our wings, but,
once again, I'm going to do a little bit of a reverse fold on this, just to make it
work a little bit better. Specifically, I need to unfold my wing
here and unfold the wing here. I'm going to unfold this trapezoid shape but not
all the way, maybe about half way. It looks kind of like a bed. I've got a flat
part here and a vertical part here. Now, the reason I'm doing the vertical part
here, not all the way folded, is because I need it to be able to reach far enough.
So, if it's upright a little bit, it has enough space to reach. Let me show you
what I mean. Coming into these folds, hopefully you
can see, I have a number of creases inside. And the important crease here is
this one and this one. What I need to do is take my fingernail to the other side
and give it a little bit of a scratch. And I just want to reverse that same
crease, just like I did before. So coming up here to the corner,
that's going to fold right to that center line. Again, it's not going to work
if this is all the way flat, because it just won't quite be able to reach. So we
will need to make sure that's upright. The line is reversed, and the corner
folds right into that center line. Obviously, I'll do that on one side, a
little bit of a scratch over here, and then I can bring this corner in to match.
Now, believe it or not, this is called the Cobra because of this step.
That's supposed to be the hood of a striking Cobra. I think it looks kind of like a
shirt, but, hopefully, you get the idea. Now, if those corners are together, I can
bring this down and start to match that with the edge of the wing here and the
edge of the wing here. The shape should compress to the same shape that it has
underneath. Those should match here and here just exactly. Another great
opportunity for my marker just to slide that out to the edge on both sides.
Now, if you have a shape like this, you're almost done. Once again, we just want to
fine tune a little bit. Make sure everything matches the edge of the paper.
And then, we'll fold it all in half, going this way, leaving our folded edges on the
outside. This is a chance to match those corners, and, as I have mentioned so many
times, little extra symmetry never hurts. So, just making sure those line up and
are pretty close to the same is really going to help us, when we fly.
Now, for the last step, we're going to make the wings. And, as you saw in the
initial design, like our Nakamura, for example, we're going to use that same
principle. Take the leading edge of the wing, this long line not little short
line, the long line here and just pinching it, rolling it, bringing this
edge all the way across, so that it's parallel with the bottom of the plane.
That, again, builds in an angle on the wing, that deflects air downwards like
angle-of-attack. But it's built into the plane, so we can refer to that as an angle
of incidence just like you saw before. Now, once that's folded, I'll flip it over,
fold the other wing to match, just making sure that I'm following this bottom line
once again. And also, that the back edge here on my two triangles, they match as
well just for the wings. Now, in all these discussions, I've mentioned the word
dihedral, so, hopefully, you remember that term. And, as I bring these wings back up,
I'm going to add just a little bit of dihedral, that Y shape that helps
really give a little stability to our airplane, as well. Now, this is a great
airplane for a lot of reasons. It's a classic design, and it flies great. But it
also benefits from a secret launch technique, so, once we get out in the
hangar, I'll show you a little bit more about that.
Okay, everyone. Hopefully, you've had a chance to fold your Cobra. Now it's time
for some test flights. I just want to show you a couple things that I think
will make that flight work a little bit better, just in the tips department.
Number one, we do have a little bit of that dihedral on that wing, so the wings
are pointing up just a little bit like the letter Y. And also you can definitely
give this a nice straight throw. But I do want to show you an additional technique
for launching the plane. If I turn it upside down, so it's pointing at me and
the back is pointing away, upside down and backwards, my index fingers just go
right along the crease here and right along the crease here. Now, I can bring
this back just like this, and, in slow motion, it might look a little bit like this.
Just bring my fingertips to opposition, just like that. And, in fact, let
me show you a couple throws, just to give you an example.
Okay, thanks for watching, everyone. Join me again for more tutorials.
Thanks very much for watching. You know, we've got a lot of really great artifacts in this
museum, and we can hardly wait until the time comes, when we can open our doors
again, and you can come and see them in person.
Until that time, we're going to be working very hard to bring you new
content, new demonstrations, new workshops, all kinds of wonderful things for you to
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