Part 3
Make a Jagwing
Transcript of the narration below
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TRANSCRIPT
MAKE JAGWING

The “flying wing” designs—so called because they don’t have that typical tail section—are efficient and work very well for air surfing. But that tail section is what keeps most airplanes stable, similar to the way fins in the back of a rocket keep it from tumbling and the way fletching keeps arrows flying straight.

 

Without a tail section a foam wing waffles around and falls out of the sky. So the flying wing designs from here on will use some cool tricks to gain stable flight. Adding a wire weight to the front gives it direction, and bending flaps in the back—up—help keep it stable. If the glider starts to dive, the wind rushing over it is deflected up. For that action up the reaction is to push the back of the glider down, countering the dive. The up flaps are called elevons.

 

So here goes the jagwing. It’s fairly easy to make if you’re careful not to rip the thin foam.

 

 

So here goes the Jagwing.

 

An engineering student in Wisconsin named Michael Thompson designed the Jagwing points to create spinning vortices of air to create lift and give the Jagwing excellent pitch stability.

 

 

Rough-cut out the jagwing pattern. Cut pretty close to the solid line on the ends so you can see to center on one of the smaller pieces of foam, with an equal amount of peeking out the ends. Use any tape, but on these ends only. I sometimes color it to remind me not to accidently cut into it. Do not fold the tape over to the other side of the foam.

 

Cut exactly on the solid line in the back and snip out this little notch in the middle. Then cut the points. I cut them all one way then all the other way. Make sure some tape on each side remains to keep the pattern attached to the foam.

 

Stick the pattern and foam in a book so only the back and dashed lines peek out. Push down the paper pretty firmly to establish a fold on the dashed line. This is the elevon we talked about earlier. Turn 90 degrees so the middle dashed line peeks and fold down again. This middle fold makes “dihedral” in the wing which we’ll talk about in a minute

 

We’ve been working on the glider upside-down. To avoid confusion I’m going to mark the foam side “TOP” before I separate the pattern from the foam by cutting those solid side lines that I so carefully avoided cutting until now. Save the paper pattern for another glider. So this is the top of the foam glider. The back elevon should slant up. I like to carefully give it a little more bend up with my thumb.

 

Also make sure that your wing slants up slightly from the middle. This is called dihedral and almost all airplanes and gliders have a little dihedral to keep from slipping uncontrollably sideways. You only need a little bend. If you push one side flat, the wing tip of the other side should lift off the table about ½ inch or 12mm.

 

It doesn’t glide yet because—remember—we need to add weight in the front. Pull out one of the 4 short copper wires. Use a really small piece of tape to attach it to the front in the middle. I tape on the top but I don’t think it matters. It does matter that almost all the wire should stick out. Make a little bend in the other end so the wire doesn’t poke someone in the eye.

 

Start off with the wire bent all the way back, like this, unless it stalls. If it stalls, bend it out to the front more.

 

If all is well, you should be able to just drop the glider and it will fly. Most gliders would fall out of the sky at such a slow speed but that goes to show just how efficient these are. Pinching the very back between thumb and finger, tilting down slightly and pushing gently only to flight speed launches it even more smoothly and directionally. If it always turns one direction… let’s say it always goes to the right, then bend the most left point up a little to correct the turn.

 

FLYING FIXED WING WALKALONG GLIDERS.

 

I’m assuming you’ve already know how air surfing works and you have some practice with the tumblewings. If you prop the front of your jagwing up a little with the wire you might be able to take off from your board and land. It takes some practice; you have start walking forward and tilt the board at the same time.

 

The biggest problem people have is letting their gliders get ahead of the board, and it actually makes the gliders dive to the ground. Here’s why. If you’re walking along with the glider above and not far in front of the board, the upward air keeps it up like it’s supposed to. But if the glider gets ahead, the upward air mostly hits just the back. That makes the glider pitch down and chasing after it only speeds up the dive. Try walking into the launch, and launch high. Never let the glider get very far ahead of the board. In fact, if you go so fast that the glider goes right over the top of the board, you’re close to where you should be.

 

You can make your jagwing fly even more efficiently by curving the front of the wing. You might have curved one or two points UP to correct a tendency to turn, but here we curve all the points down, even ones you might have curved up earlier. (If the turn shows up again you can bend the point up again.)

 

How much bend? Well, if you cut out this gage—and I’m going to color it for contrast--it shows how much bend should be in those 2 jags next to the middle jag. You can see if your wing curve follows the gage curve from below or use the other half and gage it from above. Once you have these two curved, bend the other points similarly.

 

But now with the front of your wing slanting down, your glider might start to dive. There’s a paradox here: the curved-down front of the wing provides greater overall lift, yet it also makes the glider point down more. So if the glider starts diving or going down too fast, we should be able to snip off a little bit of the wire weight to get lighter, more efficient flying. If you snip off too much, though, so it stalls and waffles like this you’ll have add some weight back. Tape works well.

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