Category: Forces / Motion / Physics

Tags: science, forces, motion, physics, glider, gliding, keystage2, keystage3

The foam gliders have come a long way since I made this video. For instructions and patterns, thin foam (or cut your own from scrap packaging foam), go here: http://www.sciencetoymaker.org/airSurfKit/index.htm A glider becomes a walkalong glider when you can create a wave of air and surf the glider on the wave indefinitely, which looks like magic. My middle school technology students have been making and flying paper walkalong gliders. But I've been searching for a walkalong glider design that's easier to make and fly, for first-time fliers. I found it in a Wisconsin college engineering student's work. Michael Thompson figured out how to slice ordinary white styrofoam--either recycled electronics packaging or insulation sheets from building supply stores---into very thin slices. Then he cuts and forms them into slow-flying gliders, including his famous Jagwings. Foam gliders are fast to make, slow flying--great for a starter walkalong glider. Michael sent me a glider and patiently taught me about them. Soon my students and I were making them, flying them and innovating variations, and you can too. It's too early to make instructions yet, but here are some notes of what I've learned so far. Mike Thompson has agreed to make foam sheets available inexpensively. For just a few dollars you can get plenty to experiment with. His e-mail is: flyingwingbat at yahoo.com Replace the "at" with @ (I do it that way to foil spambots). His prices include postage because he can send them in an envelope, and that makes it easy for him to fill orders outside the U.S. ABOUT THE VIDEO I've been experimenting with a simple hot wire foam cutter. This is the crude prototype I'm experimenting with. The hot wire is inexpensive nichrome, which is short for nickel chromium, 40 gauge, about 3 thousandths of an inch (or .076 mm) as thin as human hair. When you pass electrical current through nichrome wire there is resistance, electrical friction in the form of heat. Think of toasters. I don't get it hot enough to glow orange for longevity and safety, but it's hot enough to make a smooth, precise cut through foam. I found that two 9 volt batteries hooked in series to get 18 volts was the perfect power source for that length. I made a momentary foot switch so I don't drain the batteries when not actually cutting. To set the thickness at which the wire will cut the foam, I started with bare 20 gage wires at the edges. That's too thick, so I shimmed it with folder paper (oaktag?) and or printer paper, depending how much to shim. The wood base is protected from the how wire with aluminum foil (the wire will get stuck in the wood and break. Denser foams (electronic packaging) can be cut thinner than less dense foam (from building center). As a rule of thumb, I cut as thin as I can without ripping out holes in the foam when I try to separate off the thin sheet. MAKING A GLIDER Tape on a pattern in two places and cut on the line, cutting through the tape last. Separate the foam from the pattern. Cut out a thin strip of paper from the pattern and tape it onto the front. Decide which side will be up. Bend the back tips (elevons) up. Bend the sliver of paper down (what angle will will be one of the things you experiment with). If it goes down too fast and you can't correct it by changing the angle of the paper, you might have to cut off some paper. If it dips (stalls) and you can't fix it by changing the angle of the paper, you might have to add TINY bits of tape to the front end of the paper. If the glider turns slightly, don't worry about it, but if it turns hard, bend one elevon up more, the elevon opposite the way it's turning. You can also bend the leading edge up on that same side up. If the severe turn persists, try making the opposite bends on the other side. To fly the walkalong glider once you get it adjusted, see this video http://www.youtube.com/watch?v=7d80Mn8Rtik It's about flying paper gliders, but it applies to foam as well.

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