Walkalong Gliders from an Envelope
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Below, you can find more details here about steps covered in the video. Use the numbers in the upper left corner of the video to find the corresponding number here. If you still have questions, feel free to contact me . For illustrated instructions that you can print out, go here (PDF document).
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Illustrated, print-friendly instructions
1.) On this page you can find details about how get your flattened gliders from an envelope to fly—more text than can be put in the video. The numbers correspond to numbers in the top-left corner of the video. We like to send gliders in envelopes because people can try air-surfing very inexpensively; little packaging; and no customs hassles for for international order. However, the ready-to-fly gliders have to be flattened and sandwiched in protective cardboard. Here and in the video you can see how to un-flatten the gliders and learn to surf them on an invisible wave of deflected air. High school students of the Williamsport High School improv group, Without a Cue, present the information on camera better than I could.
To buy an envelope of gliders, go here. The price includes postage, and the money supports science education.
2.) Take the gliders out of the envelope. Be really careful because they are very delicate--easy to rip or scrunch. Walkalong gliders have been around for decades, but still they are almost unknown. Although the gliders can be made of more durable foam or even paper, those gliders are relatively heavy and fly fast. But as I have taught many students to learn to fly, we found that lightweight, slow-flying gliders are much easier to learn to fly. The foam in these gliders is only about 5 times heavier than air! It is worth it to learn to be careful when handling the gliders.
Static Cling Alert! Although we pay extra money so that the envelopes are not supposed to go through postal sorting machines, in reality it happens anyhow sometimes. The cardboard protects the gliders, but the sorting machines impart static charge to the outside rectangular sheets of foam, so they stick to the cardboard. This happens particularly in dry (low humidity) weather. It does not seem to affect the gliders, just the outside sheets of foam. If the static has not dissipated by the time you are ready to make more gliders from the sheets, then sprinkle some water on them and let them dry. Unlike paper, the foam will not warp as it dries.
3.) Know which is the top of the glider and which is the bottom. It is beyond the scope of these instructions to explain the aerodynamics of the glider (a video about that is coming soon) but the wire weight in the front of the glider keeps it from stalling. It is taped to the BOTTOM of the glider. For now, bend it down 90 degrees. Later, you will adjust it exactly.
4.) Reestablish the folds that were in the glider. If you look at the illustration of where the folds go, you might be able to see where they were on your glider. If you still can not tell where the folds were, then here is a pattern (print out with no scaling). Bend the front folds down about 30 degrees; bend the back flaps up about 30 degrees. The first time, you should check the angles with the angle gauge.
5.) Launch to see what adjustments are needed. You have to see how it flies and you need very still air--probably not outside and not near air vents. Hold the glider as shown, with only one finger on top. Two fingers on top tend to make the wings slant down--not good for stable flight. A thumb and finger on the bottom, with just one finger on top, tend to make the wings slant up slightly. That slight upward slant is called dihedral and it helps flight stability. You can give the glider a very gentle push forward, but you don't have to. You can just tilt the front downward little and let go. As it glides, notice how it is flying. Does it stall (bob up and down in peaks and valleys; does it dive (the opposite of stalling); does it turn continuously to the left or right? If it does any of these, air-surfing will be easier if you adjust the glider.
6.) Fix stalling or diving. How much weight is in the front determines whether the glider stalls, dives, or flies well. But you probably do not have to add or cut off weight. By bending the wire forward or backward you can adjust for stalling or diving. Just as an experiment, if you fly the glider with the wire tucked all the way back (the way it was folded when in the envelope), then it stalls massively when you launch it. But as you bend the wire forward more, it stalls less. Keep bending the wire forward until it does not stall anymore, or just stalls a little bit. You should not have to add weight;.but if you do, a little bit of tape on the wire should do the trick. But before you start adding tape, check to make sure your angles are correct.
7.) Fix turning. If the glider always turns in one direction when you launch it, and it keeps turning that way throughout the glide, then it needs to be adjusted. In the video, the glider keeps turning RIGHT, so we bent the LEFT back flap (elevon) UP a little. But if you have to bend it a lot, it is better to bend the other side down. So you could also bend the RIGHT back flap DOWN a little. If flaps get bent at too steep an angle, then they put too much drag on the glider. By the way, you might have to re-adjust the front wire a little after changing the back flap angles.
Learn to fly the glider with a board. It is best to have a large piece of cardboard, like a pizza box, to divert the air. If I could walk next to you with both of us holding onto the board, then you could get a feel for flying in a minute or two. But you are in a part of the world where such a thing has never been seen, with nobody there to help you. So it will take more time to learn, but it's worth the effort to be the first in your region to surf a walkalong glider. Following are some common mistakes people make when they start learning. There is also a video with more extensive visual hints for learning to fly.
8.) Keep the board tilted. If the board is horizontal, it just slices through the air. But if you walk with the board tilted, it forces the air to go up and over--creating a continuous wave of air to surf on. Most people unconsciously flatten the board, which is ok if you want to land the glider on the board, but it's not good for keeping the glider levitated. And do not swish the board. That just make turbulence.
9.) Keep the top of the board so close to the glider that it almost blows over. Another reason that gliders fail to stay up is that people do not keep the board close enough to the glider, so it goes down slowly. But if you know the trick, you actually make the glider gain altitude dramatically. If you practice getting the top of the board really close to the glider, you will see the glider bump up higher. It might actually go over the board--that's good practice. But instead of letting it go over, try to raise the board so the glider cannot go over. Instead, the glider gains altitude. Once you have that breakthrough of realizing that the top of the board must be closer than is intuitive, then flying will be dramatically better.
Related to that, do not let the glider get much lower than the top of the board, or it will be difficult to maintain altitude.
10.) Learn to turn. For beginners, the glider seems to turn capriciously to the left or right, but actually they control turning. If you learned the pervious step about keeping the top of the board close to the glider, then learning to turn will be easier. To turn the glider, push one corner of the board toward an outside corner of the glider. Tilting (banking) the board to the corner is actually higher than the glider allows you to make very sharp turns. In fact, you can turn so sharply 180 degrees that you will actually hit your own turbulence. See if you can fly through the turbulence.
11.) Learn advanced flying. There are lots of challenges that you do with walkalong gliders. Try landing on tables or steering around objects. Air jousting "dog fighting" is very challenging, but lots of fun.
It's also very challenging to divert the air with only you hands instead of the board, but looks even more magical. Before you even start, bend the front wire forward more, so there is no stalling at all. Then the trick--other than lots of practice-- is to find the sweet spot. I suggest that you launch the glider high above your head and try to touch the back edge of the glider with your finger tips. When you get close, you should see the glider bump a little. And you have to keep your hands in exactly the right place relative to the glider. If you get just a little too far ahead, the glider will stall and your hand will be even further too far ahead. If your hands are just a little too far behind, then it actually makes the glider dive. If you supplement your hands with your head or body, then you get more lift. I have seen young kids with small hands still manage hand flight by getting more lift that way. Steer by shifting your hands just a little left or right.
Flying with only your head is particularly difficult to steer.
Your envelope contained two rectangular sheets of foam that were not yet made into gliders. If they have static cling (sticking to the cardboard) then sprinkle a little water on and let dry. Here are some instructions to make gliders from the foam sheets.
12.) Repair your glider .Gliders can last forever once people learn to handle them gently, but accidents do happen. I love the challenge of repairing gliders. For rips, use VERY thin pieces of tape (red on the video, to show up) and use as little a possible. Then you might have to readjust or add a little weight to the front.
Nervous hands often put unwanted bends in the gliders. These are actually more challenging to fix than rips. Counter bend as best as you can. Putting the glider in a book, adding weight on top and leaving it overnight can help bring a glider back to flat. If a glider is being particularly difficult, I add both a little more weight to the front and a little more upward bend to the elevons (back flaps).
13.) Rate, subscribe and spread the word. If the video was worthwhile to you, give us a thunbs-up and subscribe for more science project videos. And let other people know about walkalong flight.
14.) Many thanks to Williamsport High School's Without a Cue acting students, directed by Mrs. Marie Fox, for presenting on camera. Performances are generally the last Friday evening of months, during the school year. The Without a Cue YouTube Channel is here (coming soon))))))))))))))))))))))))))