About Front Weight

Why You Need Front Weight on "Flying Wing" Gliders, and What to Use

Notes: 

  1. I do not include weights when I send boxes of foam sheets because the sheets can be made into various gliders, requiring diffenent weights. But don't worry. You can easily make your own weights at no cost or almost no cost
  2. If a video would be helpful for figuring out front weight, then skip through this video until 6:32 (or 6:10 if you are unsure about folding angles too).

Why you need front weight.

Mosquito, Jagwing and other "flying-wing" type air-surf gliders--that are all wing and no tail--are the best to fly as walkalong gliders. Since they do not have a tail, they need weight in the front and flaps in the back for stable flight. Here’s how it works:

If you drop a glider with rear flaps but not enough front weight, it stalls.

If there is too much weight in front and/or not enough bend in the rear, then the glider dives.

When the rear flaps (elevons) and the front weight are balanced the glider does not stall or dive.

As per Newton’s 3rd law of motion (action and reaction), when air is forced up by the back flaps, the reaction is that the back of the glider is forced down, which is the opposite of a dive. When you get it adjusted correctly, the front weight and back flaps balance out each other perfectly. The weight prevents stalling and the flaps prevent diving. The result is efficient, stable, elegant gliding!

What to use for front weight: aluminum foil, copper wire

Aluminum foil

We think of aluminum as a lightweight metal--and it is compared to other metals--but it is still over twice as dense as water.

A strip of aluminum foil about 13 mm (1/2") wide, then crushed and rolled into a sort of wire, is an excellent front weight.

Aluminam foil is more widely available but it can be a lot of work if you are making lots of gliders.

Copper Wire

copper wire works better if you are making a lot and you want fast production.

The easiest way to adjust front weight.

Getting “flying wing” gliders adjusted will become intuitive and easy, but it can be confusing at first. I suggest starting by:

  1. Bend the back flaps (elevons) to about 45 degrees up, then…
  2. Add weight to the front until the glider does not stall in test flights. But it the glider dives, you might have too much weight. Then, when you are close...
  3. If the weight is long and thin, you can micro-adjust by bending it more forward if it stalls, or more back if it is diving. This shifts the "center of gravity" or balancing point of the glider. Bending forward is just like adding more weight. Bending backward is just like cutting off weight.

Contact me if you still have trouble with getting gliders adjusted.

Ultra Light Foam Ready to Fly Fleet




Temporarily out of stock -- We are making some changes to this. I'm also working on a video about Ultra Light Foam. 

At 6 to 7.5 kilograms per cubic meter density, Ultra Time Warp Asia is astonishingly lightweight--only about 5 times more dense than air! Because these gliders weigh less, they have a much thinner front wire. Time Warp Asia foam is more delicate and easy to tear, but if you can handle it carefully you'll experience almost magical, slow, efficient flight. I use gliders made of it both for teaching beginners how to fly--because the slow flight gives them time to think and react--and for advanced flight projects like hands-only flying because they are so light and efficient. Here is how to fly.
Here are tips about teaching groups to fly air-surf gliders.
Read these notes before ordering.

Back to Air Surf Shop
 

Slice Your Own Foam for Walkalong Gliders (Hotwire Cut Foam)

You can find more details here about steps covered in the Hotwire Cut Foam for Walkalong Gliders 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 .

Note: The names of the foam types have been changed.

  • Time Warp North America foam is now called Time Warp Foam.
  • Time Warp Asia foam is now called Ultra Light Foam.

We no longer sell the hotwire foam-cutting kit because now there are several good ways to cut precisely without the special bronze machined part. Learn more about here.

If YouTube is blocked at your school, video try this MPEG file (33 MB) file. Depending on your browser it might stream when you click, or you might have to right-click and "save as".

This is an add-on video to the video above. It shows how to make a hotwire foam slicer with common materials:

Introduction

1.) On this page you can find details about slicing your own sheets of foam for walkalong gliders—more text than can be put in the video. The numbers correspond to numbers in the top-left corner of the video.

2.) Walkalong gliders are so efficient that you can surf them on a wave of air, similar to the way that large birds can soar on updrafts of wind. But the gliders have to be efficient; you can’t just make them out of anything. Before showing you how to hot-wire cut foam, I will show why foam works better than paper, particularly for starting out.

3.) If cutting your own foam is too much, you can get thin sheets of foam cut on a robotic CNC hotwire cutter inexpensively from the Gliders and Foam Store.

4.) Or you can hot-wire cut your own foam sheets from scratch with an electrically heated ni-chrome wire, using recycled packaging foam and a common car battery charger.

Paper vs. Thin EPS Foam

5.) Everybody wants to use familiar paper at first. But thin sheets of common expanded polystyrene or (EPS) foam are many times lighter and stronger than paper. EPS is the white foam made from spheres or beads, that’s widely used for insulation and disposable packaging.

EPS foam can be as low as 6 kilograms per cubic meter. When you consider that air itself is about 2.2 kilograms per cubic meter, then you can see that EPS foam is only about 5 times denser than air! It almost floats and it is able to stay rigid.

6.) Let’s compare paper to EPS foam. 10 sheets of printer paper--cut to the standard size I use for gliders--are over 16 grams. 10 sheets of EPS foam only weigh 2 grams. Printer paper is 8 times heavier and still not stiff enough to keep from bending too much. It would take a thicker piece of paper to have the same rigidity as the sheets of foam even under ideal circumstances (dry air). When the air is humid, paper becomes even more limp.
The measure of 2 grams for 10 foam sheets is an average: 5 sheets each of the 2 kinds of foam that I work with. 10 sheets of Time Warp Asian (Ultra Time Warp) foam weighs a little less, 1.3 grams. North American (I call it Time Warp) foam weighs a little more, 2.5 gm. The point is, even the heaviest foam is many times lighter and stronger than paper.

7.) You can also see the difference between EPS and paper when you drop a piece of paper and a piece of foam.
The extra weight of paper creates a vicious spiral. Because the paper walkalong gliders are heavy, they fly faster.

The wind rushing other the wings creates fluttering in the paper, requiring even stiffer paper and more weight. The extra weight also requires a front weight that is much heavier, to balance the body. I also find heavier gliders to be difficult to adjust (trim).

Big Mouth Tumblewing
Paper Airplane Walkalong Gliders by Phil Rossoni
John on Conan. His paper designs—including the classic Tumblewing that he invented--are in his books.

How Kit Works

We no longer sell the kit because now there are several good ways to cut precisely without the special bronze machined part. (You can get nichrome wire here. Get 30 gauge for rough cutting and 38 gauge for the fine cutting.) Learn more about making your own slicer with common materials.

8.) The sciencetoymaker kit allows you to heat ni-chrome wire—the same kind of wire that you see in a toaster--first to rough-cut blocks of recycled foam, and then slice very precise sheets.

The kit supplies several difficult to find items, including ni-chrome wires, bronze threaded and machined parts that allow very precise cutting; while you supply the bulky but easy-to-find locally things: a flat board; threaded rod from the hardware store; a 12 volt car battery charger. The sparks look scary, but you can not get a shock from 12 volts unless you stick your tongue on the wires.

9.) Parts List (that you supply):

  • Smooth, flat board, preferably at least as big as 30 cm x 40 cm (12” x 16”). It should be at least 12mm (½”) thick. Thicker is better). You might be able to use something that you have around, like an old shelf or something
  • Threaded rod—at least 6 mm (¼”) diameter. In North America, threaded rod usually comes in 36” lengths at hardware stores and costs a couple of dollars. Perhaps 1 meter lengths of M6x1 are available in other countries.
  • 12 volt car battery charger (or hook directly to a car battery). Although these will make impressive sparks if you click the leads together, you can NOT get a shock from 12 volts unless you lick them—even if your hands are wet. 2 amp or higher car battery chargers are definitely powerful enough. I tried the cheapest 1 amp charger that I could find and it worked. If you don’t want to buy one, you probably know someone who can loan you one. Or you can get them at auto parts stores or department stores.

Tools You Will Need:

  • Drill, drill bits, hack saw, pliers, screwdriver.

10.) You rough-cut blocks of foam with the thick ni-chrome wire. Then you fine-cut the foam into precise sheets with threaded, notched bronze “L” pieces and fine ni-chrome wire. You fine-tune the thickness by turning the Ls in or out.

Make the Hotwire foam Slicer with Common Materials

Full Transcript of the Add-On Video

The best source for small amounts of nichrome wire is Jacobs Online. Get 30 gauge for rough cutting and 38 gauge for the fine cutting.

Hi it’s Slater. This video is an add-on to a detailed video about hotwire cutting foam paper. That is, making thin sheets from blocks of expanded polystyrene foam for walkalong gliders; or thicker ones for dragonfly helicopter wings. Getting the right foam thickness for the gliders requires very precise positioning of the hotwire. In the past video I featured a special bronze part for doing that. A machined groove lifts and lowers the hotwire. It works well, but wouldn’t it be good if you could use an ordinary, cheap, bolt that’s available locally? This video shows two ways to do that.

You cannot just have a bolt that’s threaded in, like this. When the bolt is turning and going down, the wire against the thread is moving up—so it doesn’t actually move at all. One strategy that does work is to drill out the holes a little bit too big for the bolt—it slips through. But the hole has to have a bottom—here I’ve flipped the board over and I’m gluing coins on the bottom. I also made some hot glue feet so it’s stable.

The bolts slide in. When rigged with the wire, the turning bolt does not move up or down; but the wire against the thread does. You can hook the car battery charger directly to the bolts. Here I’m cutting a thick piece for a dragonfly helicopter wing.

These are actually ¼” or M6 threaded rods. A finer thread like this would give more precise adjustments.

A different strategy—even a bit more precise--is to add a screw that’s flat on the bottom here and usually has a round-head on top. The wire is always a little higher up on this outside screw. When you turn this inside screw right next to it, it places the wire very precisely to the right height—both down and up.

As with all hotwire cutters, the resistance wire is kept under some pull tension, in this case rubber bands. I hook the car battery charger to the outside screws—drywall screws.

The sharp ends of the round-head screw are sticking out the bottom, so again I’m making little hot glue feet to raise the bottom up

Thanks to Sekino san in Japan for coming up with this design.

Here is Mr. Hirohisa Sekino's hotwire foam slicer page.

Thin nickel-chromium resistance wire is very cheap and you could even scavenge it from a broken soldering iron.

You should be able to adjust the tension. I think it’s easier to make adjustable rubber loops than it is to move these anchor screws. I cut and tie into an overhand knot. If you try to move the knot, it will probably break. But if you rub in some slippery soap, you can pull next to the knot and move it.

We attach the wire by kind of hooking around, then twist. If you don’t twist enough, it will pull off. Spreading the wires as you twist helps prevent that.

I hook on at one end. Then I stretch the rubber at that end as I hook the other end on or else it could break getting it on.

This is just an update. It does not replace the other video that talks about foam vs paper, how foam is not all the same, calculating density, how to rough-cut foam blocks first, how to control heat, where to get foam, etc.

I know this will sound self-serving, but even if you plan to cut your own foam—and I encourage that--it’s still a good idea to buy a few gliders. Most people bumble around and waste time trying to figure out the right thickness and rigidity for gliders.

(End of the Add-on Video Transcript)

Make the Rough-cut Part

11.) Cut the piece of threaded rod in half.

Drill two holes in the board about 38 cm (15”) apart in the middle of the board as shown, using a 6 mm (1/4”) drill bit. If you are not using am M6x1 or 1/4" threaded rod, then you will have to figure out what size hole to make for the rod to thread into.

Note: The rod is sturdier if it threads into the board. A ¼” or 6 mm drill might seem too big since it’s the same diameter as the rod. However, I’ve found that wood fibers have a little “give” and the rod still threads in (easily).

Slant the drill a bit away from the board. Otherwise, the rods tend to lean in when the ni-chrome wire and rubber bands pull them inward.

Having the rods stick out is dangerous. At the least you should put something on top to protect against getting accidently speared or poked in the eye. I just bent the threaded rod over, but don’t bend so tightly that they break.

Thread the rods in until they are sturdy.

12.) Cut a piece of the 30 gauge (thicker) ni-chrome wire [about 30 cm (12”) long]. Note that with wire, the lower the wire gauge number, the thicker the wire is. This is counterintuitive, having to with how many steps it took to draw the wire through holes to make it thinner and thinner. So 30 gauge is the thick wire; 38 gauge is the thinner wire. Twist the ends of the wire onto rubber bands so that the rubber bands are always stretched when strung on the rods. In the video my rubber bands were too long so I folded in half.

Ni-chrome wire always has to be under some tension because it expands a little (gets longer) when it heats up. You might have to fiddle a little with where to connect the rubber bands before you get it right. You can tie knots in or double-up the rubber bands if they are too long.

Rough-Cut Foam

13.) Hot-wire cutting releases irritating smoke. You could do your cutting on top of your stove if the fan discharges outside (some just recycle the air back). Or you could cut in a garage with the big door open. The smoke rises, so keep your head to the side so you don’t stick your nose in it.

I have not found reliable information that smoke from hot-wire cutting is particularly toxic or carcinogenic in the way, say, hexane or asbestos are. But it’s never smart to breath smoke.

You can reduce the amount of smoke/fumes generated by lowering the temperature of the cutting wire. The longer the distance of the ni-chrome wire between the alligator clips, the cooler the wire will be. It will then take longer to make each cut. Experiment.

Always remember that the foam has to be completely dry. Just a drop of water will stop the cutting cold.

The clamps of the car battery charger are too big, so attach the smaller alligator clips that come with the kit. Then simply clip onto the far ends of the ni-chrome wire— not too close to each other. If you need to, you can control how hot the wire gets by moving the alligator clips closer to each other. But when the wire glows orange, it’s much too hot and can break.

Measure where you want to make the cut and make sure the foam is flat on the board as you cut. It’s that simple. I cut my blocks to about 10 cm by 22 cm (3 ¾” x 8 5/8”) for both small Mosquito gliders and double big Mama Bug gliders, but you can cut whatever size you want.

Make the Fine-Cut Part

14.) Cutting the actual foam sheets for gliders requires more precision and a finer wire.
The finer 38 gauge wire breaks easier.

I suppose you could just use the thicker 30 gauge wire for your foam sheets and avoid the hassle, but it melts a bigger kerf. That melted plastic has to go somewhere. It gets deposited on the foam sheets, making them heavier. But if you hate the fine ni-chrome wire because it breaks easily and it’s hard to see, then try the thick wire even for fine cutting.

Drill two holes for the bronze “Ls” to thread into, 15cm (6”) apart, between the threaded rods as shown. Use a 3 mm (1/8”) drill. If any wood fibers stick up, scratch them off with a fingernail until it is flat around the hole so.

Unlike the rough-cutting wire where you could adjust the heat by sliding the alligator clips, you don’t adjust the heat for fine-cutting. If you are using very heavy, dense foam that cuts very slowly, you could make the bronze “Ls” closer to each other to increase heat. Or, if you want to make the wire cooler to minimize smoke when you cut—or cut a very wide piece of foam—then you can add a hole that’s farther away from the first.

Screw in the Ls until the groove is close to the board.
15.) Cut a piece of the thinner 38 gauge ni-chrome wire about 23 cm (9”) long. Twist the ends onto rubber bands at least 5 turns so it does not come off.

The ni-chrome wire will bend around the bronze Ls at about a 45 degree angle, and rubber bands will hook onto woodscrews. Hold the wire this way with the rubber bands stretched a medium about and try to guess where the screws should go. If it’s not the right amount of tension you can put the wood screws in a different position. Half of the maximum stretch of the rubber bands is good. If your wire keeps breaking, try less tension.

16.) Push the wire into the L grooves. Notice that when you rotate the L, it lowers or raises the wire very precisely.

Calibrate the wire level so it cuts slices that are the same thickness on both sides. Do this by screwing in the bronze L in until the ni-chrome wire just barely touches the board (that’s why you used your fingernail to scratch off the wood fibers when you drilled the hole); on both sides. Then screw the Ls out (counter-clockwise, so the wire is no longer resting on the board) exactly one turn. In the future, when you adjust the cut thicker (counter-clockwise) or thinner (clockwise), turn both sides the same amount.

Fine-Cut Sheets

17.) I’m going to start out with the worst EPS—molded packaging foam. It’s usually hard so it cuts slowly; and it’s heavy, as foams go. It looks like you could get some good flat sheets from it, but there are so many voids that you won’t get much. Yet, as bad as this stuff is, it’s easy-to-find and it’s still many times better than the best paper.

I hook up the alligator clips to the Ls and try cutting a slice. The first one or two cuts are never good so don’t get discouraged. Push the foam forward gently so as not to deflect the wire a whole lot. This heavy foam is a little wavy, but it will work.

18.) Here I’m going to try a lighter (lower-density) foam. Notice how it cuts faster. But it’s cutting a little too thin now, so let’s turn out both bronze Ls one quarter turn out. With lightweight foams I raise the wire a little. Perfect!

You decide what thickness to make foam. Too thick is too heavy. Too thin isn’t strong enough. A good slice has some flex, but not too much. The screw threads in the “L”s advance 1/32” (about .8mm) in each turn. That means that each time you twist the Ls 45 degrees, you lift or lower the wire by 1/10th of a millimeter.

However, if you have raised the wire .8 mm above the board, that does not mean that you will make sheets that thick .8mm thick. Some foam will be melted away (the “kerf”). How much is melted away depends on how dense the foam is; how hot the wire is; and how fast the foam travels. I find that the ni-chrome wire makes a wider kerf in lighter foams. So that means I have to turn out the Ls a little more—making the wire higher—to get the same thickness of light foam compared to heavier foam. All of this will become intuitive as you cut foam.

Measure Thickness

19.) You might not need to know a numeric measure, depending instead on getting a feel for how stiff it should be.

You can’t measure the thickness of a sheet of with a ruler. A dial gage is expensive, about $100 U.S. If you do get one, make sure that the part that touches the foam is wide, or it will crush the foam. That would give you an inaccurate measurement.

A workaround for an expensive piece of equipment is to cut 10 squares and stack them together. If 10 sheets measure 6 millimeters, then 1 sheet is 1/10th of that: .6 or 6/10 of a millimeter.
.6 mm (6/10 mm) is a good thickness to start with. If it’s too rigid and heavy, go thinner. If it’s to flimsy, go thicker.

Finding Foam

Lets step back a moment and disambiguate the common polystyrene foams. The foams made from the spherical beads are EPS - expandable polystyrene. Sometimes it is called "bead board". It is used in a lot of cushion packaging (for appliances, computers, etc.), in many hot drink cups and in thermal insulation, usually all white. It is closed cell foam. Egg cartons, meat trays, clam shell food service, some cups (with a seam down the side), and some insulation (e.g. blue and pink board at Lowes or Home Depot) are XPS - extruded polystyrene foam. It is also closed cell foam. I think that "Depron"--a common material for making model airplanes--is also extruded polystyrene.

The egg cartons, meat trays, and clam shells are first extruded into large foam sheets. Subsequently, these sheets are thermoformed into the final end-use articles. The extruded foam cups are typically two
pieces - with the side (with a seam) and the bottom being separate pieces.

I've given the strict definitions. People are sloppy on web sites and in their advertising and incorrectly use EPS, XPS, and Styrofoam names. Some people even call polystyrene "styrene" which is completely wrong. That doesn't even get into the spongy, open cell foams like polyurethane, which is used for seat cushions; and sprayed foams. There is also some kind of paper-like foam used to wrap delicate parts for shipping. Everyone thinks it will make great walkalong gliders, but is not rigid enough.

20.) Expanded polystyrene foam (EPS) foam all seemed about the same to me at first, but with experience I become aware of the diversity: heavier stuff, lighter, big beads and smaller beads. Any EPS foam will work far better than paper, but some foams are clearly better for gliders than others.

I’ve already mentioned why I don’t use molded packaging foam (heavy, slow-cutting, full of voids) anymore, but it will work in a pinch.

21.) For a long time I used discarded shipping boxes from the seafood department of grocery stores. However, these boxes are made to be strong and impermeable, so the foam is heavy and slow-cutting. Still, it was the first recycled foam that I could that would give me nice flat sheets without a lot of waste. If you don’t mind gliders that fly a bit fast, seafood packages work well. If you stick your nose up to the gliders, you get a slight whiff of the ocean!

22.) Eventually I discovered the discarded packaging foam from a furniture and appliance store. There were big pieces and then I stumbled on some foam from China that was much lighter than anything I’d seen before! At 6 to 7 kilograms per cubic meter density, it’s only 4 times more dense than air. I call it Time Warp Asia foam. When you are that close to floating, the aeronautics become different—in a good way. Glider flight is astonishingly slow and easier to adjust.

There is some foam from China that is even lower-density: between 4 and 5 kg/M3. However it has large beads (spheres) and—correspondingly—large gaps in between. The gaps do not seem to hurt the gliders. Indeed, they fly very well, but having big holes in the gliders puts some people off.

By comparison, the lowest density foam that is manufactured in North America is heavier: 11kg/M3. However is a bit less prone to ripping.

Time Warp Asia (I now call Ultra Time Warp) foam is very small part of the waste stream, but if you can make connections with a conscientious furniture/appliance place, you might find it. I get from Beiters, which has several stores in central Pennsylvania. Rob Beiter is a very conscientious person who goes out of his way to support community projects and he diverts the ultra-lightweight foam to us. I don’t know if you will be lucky enough to find someone like that but it’s worth a try. Perhaps taking some gliders in and showing what you’re doing would help.

23.) In my experience, only the bead foams work well for beginners. People do make gliders out of disposable foam plates, egg cartons, meat and produce trays (also extruded polystyrene XPS) but—as is also true of extruded blue and pink building insulation--that foam is heavy even when sliced thin. The resulting flight is fast, which is difficult for beginners to learn with. However, the heavier gliders are more durable and are better at flying outside, when there is a slight breeze. If you don’t mind trotting to keep up with it, try it. Tyler MacCready’s design used Depron-like foam.

Phil Rossoni shows how to use already thin foam to make a walkalong.

Measure Density

24.) Knowing the density of foam is the most important thing, in my opinion. I can pick up foam, feel the weight, feel the softness or hardness (lower density foams are softer—not spongy, but noticeably softer). From handling it I can make a guess of the density. But even after years of working with foam, some of my guesses are off sometimes, so I never fail to measure density the proper way and figure out the number.

To calculate density, you weigh the foam block and measure the width, length and height; dividing the former by the latter. W x L x H / Wt

In North America, foam is measured in pounds per cubic foot, but it’s easier to just figure it out with metric measurements and convert it if you have to. It’s usually expressed in kilograms per cubic meter (kg/M3). So when you are calculating, enter 6 grams as .006 of a kilogram. 22 cm is .22 of a meter; 95 mm is .095 of a meter, etc.

To give you an idea of ranges, in North America ¾ lb/ft (=12 kg/M3) density is light (one or two N.A. companies make it as low as .7 lb. density); 1 ½ lb/ft3 (=24 kg/M3) density is heavy; one pound density foam (16kg/M3) is average. But if you are fortunate to find foam from China (Time Warp Asia) you can find density of 6 or 7 kg/M3. Light foam cuts faster and easier as well as flying more efficiently and slowly. I send a sample of Time Warp Asia with the foam cutting kits so people know what it is.

Once you have thin sheets of foam, anybody can cut and fold them into walkalong gliders. So you can practice a kind of aeronautical alchemy; transforming scraps of packaging foam into gossamer flyers that soar like birds.

There are many more videos and text pages in this series about walkalong gliders: How to fly them; how to make the small and big gliders; how to mass-produce gliders; how to repair gliders; and how to go about designing your own gliders.

 

 


Odds and Ends

Here is an earlier web page and video about hot-wire cutting foam for walkalongs, via WayBack Machine. Some of it's out of date, but you might glean something from it.

Here is an even earlier web page and video about hot-wire cutting when I was still using batteries, from 2011! (again, via WayBack Machine)

And this was my first foam glider from 2010!

All links about how to make walkalong gliders when you have the thin foam sheets, where to get thin sheets if you don't want to make them, how to fly the gliders, what you need to know to create new walkalong glider designs, etc. are here.(Instructions and patterns are linked there.)

Jim Annerton's design solved the problems that I was having with shims.
Jim Annerton's design solved the problems that I was having with shims.

Jim Annweton's Design: I got some really interesting DIY cutter feedback from Jim Annerton of Huntsville, Alabama. Years ago I started adjusting the distance between the board and the hotwire with shims--and I hated them. They would slip and compress and generally cause problems, so I was happy to leave them when I discovered that I could use screw threads instead of shims. But Jim's design avoides the problems I had with shims by piling up very thin brass washers (some as thin a 0.005") which are skewered on upright clevis pins. So unlike my shims that would slip and slide, Jim's stay put. Then, a compression spring is also skewered on the clevis pin and is held under compression with a cotter pin at the top. So the wire always stays at the right level.

Jim's design might not be for everyone. Jim had the stuff around his shop, but if you have to buy the special brass washers (though knifemakers suppliers), then you could be getting into some money. But it's a brilliant design and it solved the issues I had with shims. Jim reports that when he flew his gliders, "My two granddaughters (aged 7 and 4) loved to watch and try them. The first words out of their mouth when they saw them was, "How are you doing that?" :)" And Jim is already scrounging for foam at his local furniture store and experimenting with Asian foam.

I'd like to know how this project goes for you. I'm happy to answer questions about it. Feedback from you is an important way for me to know what works and what needs clarification.

All About Foams for Walkalong Gliders

How EPS Foam Stacks up Against Paper for Gliders

It is difficult for people to understand that paper is very heavy when compared to foam. But imagine how heavy these stacks would be if they were books or newspapers instead of foam! The foam is cut into thin (0.6 mm) sheets, many times lighter than a sheet of paper of equal rigidity.

What is EPS foam?

EPS (expanded polystyrene) foam is the ubiquitous white foam made of spheres (beads) that appear as circles when cut, used to make everything from foam cups to foam coolers to molded electronics packaging to sheets of rigid insulation. It is made from hard, dense plastic polystyrene beads that are “puffed up” (expanded) like popcorn or puffed rice: mostly air. The expanded spheres are fused together.

Expanded Polystyrene foam is made in different densities (the ratio of weight to volume). In North America, density is usually still measured in pounds per cubic foot. In most of the rest of the world it is measured in kilograms per cubic meter.

There are lots of other kinds of foams—and I have experimented with many—but EPS always comes out on top, because it has the highest strength/weight ratio.

Why is EPS foam better than paper for walkalong gliders?

Not only is the sheet of printer paper 8 times heavier than sheet of foam with the equivalent surface; the paper is still not stiff enough to keep from bending too much. Everybody has wishful-thinking that paper will work well for walkalong gliders. It doesn't. And thin .6 millimeter foam is inexpensive to buy, or you can even slice your own.

Everybody wants to use paper because we are so familiar with paper airplanes and origami. But to match the rigidity of a .6mm slice of EPS foam requires a thickness of paper that is many times heavier. Weight is bad for gliders, at least when you are starting out. Heavy gliders fly fast. That’s ok if are good at walkalong flying and you want to race but bad for beginners, who need time to think and react as they learn to fly. There is an exception. The rotating kind of paper glider invented by John Collins (the Paper Airplane Guy)that he calls the “Tumbling Wing” and uses the Magnus Effect, flies more slowly. However, most people find the paper spinning gliders more difficult to launch and fly than foam gliders; and in humid weather, paper becomes limp and useless. But paper is free. You can see some paper designs here.

What is Time Warp Foam?

The lowest density EPS foam made in North America is custom made for me, specifically for gliders. It weighs 0.58 pounds per cubic foot (9.3 kilograms per cubic meter). For comparison, the lowest density EPS foam commonly available in North America (usually as insulation, sold in building supply stores) is 1 pound per cubic foot (16 kilograms per cubic meter). And it can be even denser.

I have to get the low-density foam a truckload at a time (shipped as a bunch of giant blocks measuring 3’ by 4’ by 8’) because there is no commercial use for it in North America. I do not mean to discourage do-it-yourselfers who want to cut their own foam.  Even commonly available white insulation foam is much lighter than paper. And if you can find a furniture store where they import from China, you might be able to find lower density foam there (see below). It is used as packaging/padding for the furniture. You can see how to cut your own foam here .

Unless otherwise specified, the gliders and foam sheets sold by sciencetoymaker.org are Time Warp. UltraLight foam (see next entry) is even less dense, but it has to be imported.

What is UltraLight Foam?

There is also a special foam called UltraLight. In Asia (particularly China; I've heard maybe also in India) the manufacturers are allowed to use much higher concentrations of the bead-expanding agent, pentane. Pentane is regulated in most other industrialized countries. This EPS foam from China can have density as low as 4.5 kg/m3. If you consider that air itself has a density of about 1.225 kg/m3 (depending on altitude, temperature, etc.) then it’s is only about 4 times heavier than air, which is quite remarkable! By comparison, water is about 800 times more dense than air and paper is over 500 kg/m3 density.

So I call this extremely low-density foam that can only be made in other countries “UltraLight foam”. It is slightly less rigid than Time Warp foam and also a little more delicate to handle (rips more easily). But if you can handle it gently, the gliders made from it fly so slowly it's like magic!

Ultra Light foam is not actually one foam, but many similar foams from 4.5 to 7 kg/m3, manufactured throughout China. Each kind has it’s own personality and cuts differently. I do not usually make the foam that’s less than 5.5kg/m3 into gliders because that stuff has very large beads with very large gaps in between. The gaps do not affect the flight, but it does rip even a little more easily. Perhaps I will make it available to experimenters if there is interest.

So where do I find this royal class of extremely low-density UltraLight foams? In the recycling bin!! My good friend Rob Beiter manages several furniture/appliance stores in central Pennsylvania and has better things to do than collect foam scraps from packaging. And yet he kindly directs the rare bits of UltraLight foam from imported furniture packing my way because he supports recycling, science education and non-profit organizations like the Physics Factory.

Although Rob gives us the foam gratis, there is still a lot of processing. So recycled UltraLight takes lots of time for me to sort through, test density, custom cut, etc. (and there's not much of it), so it’s therefore more expensive. If you decide to cut your own foam, you might be able to find and recycle it locally—I recommend that highly

Under ideal circumstances (dead still air, people who can handle it very carefully) the ultra low-density UltraLight foam flies so slowly that it will take your breath away! That slow motion gives beginners lots of time to think and react, so I like to use it when teaching people how to fly. And again when learning to fly with hands-only deflecting the air up. You have to keep your hands at exactly the right place relative to the glider for hands-only flight, constantly recalibrating. That’s easier to do if the glider is moving slowly. Warp gliders are also superior when flying in small, cluttered rooms.

I see pinholes in my sheets of foam—is that a problem?

EPS (expanded polystyrene) foam is made of spheres (beads) that appear as circles when cut thin. The holes between the circles rattle some people, but do not affect flying. Foam gliders are superior, both for beginning and advanced flight.

EPS (expanded polystyrene) foam is made of spheres (beads) that appear as circles when cut thin. Because EPS foam is made of expanded spheres, fused together, there are tiny voids between the beads. When we slice the foam very thin, the voids appear as tiny holes. I have experimented with solid foams like Depron that do not have voids, but invariably they are less satisfactory because they weigh much more.

The pressure differential between the top of the gliders and the bottom is very small. The relative viscosity of the air going through tiny holes is high. So the pinholes might be an esthetic problem, but not a flight problem. The lowest-density Asian foam (4.5 KG per Kilogram) has bigger beads, and therefore bigger voids (again, they do not negatively affect flight but do rip easier).

Can you slice your own foam?

Yes, you can collect and slice your own foam. This page and associated video show how. Flying even with heavy foam is many times better than flying with the lightest paper gliders. And if you can find packaging foam from China (see Ultra Light foam section) you will love it. Cutting foam is quite easy when you have Nickel-Chromium (ni-chrome) wire, which is special for two reasons. It is high resistance, so it creates heat instead of a short circuit; and then it stays strong even when hot (unlike regular steel wire). Almost all electric heating devices--from hot plates to water heaters, soldering irons to coffee makers--use ni-chrome wire. It's the stuff that glows orange in toasters, although we don't use it that hot to cut foam.

Hot wire cutting produces some smoke. You are responsible for cutting in a well ventilated place, such as a garage with the big door open; or under a stove exhaust hood.

Paper vs. EPS foam: The numbers

Flying even with heavy foam is many times better than flying with the lightest paper gliders. And if you can find packaging foam from China (see Ultra Time Warp foam section) you will love it. Cutting foam is quite easy when you have Nickel-Chromium (ni-chrome) wire, which is special for two reasons. It is high resistance, so it creates heat instead of a short circuit; and then it stays strong even when hot (unlike regular steel wire). Almost all electric heating devices--from hot plates to water heaters, soldering irons to coffee makers--use ni-chrome wire. It's the stuff that glows orange in toasters, although we don't use it that hot to cut foam.

Hot wire cutting produces some smoke. You are responsible for cutting in a well ventilated place, such as a garage with the big door open; or under a stove exhaust hood.

10 sheets of paper weigh over 16 grams.
10 sheets of thin-cut EPS foam weigh only a couple of grams, and the foam is still more rigid than the paper.

The density of EPS foam is as low as 6 kg/cubic meter (Ultra TW foam). Time Warp foam is 11 kg/m3 (and stronger). Paper is 540 kg/m3. That's not really fair because paper is thinner than foam sheets used for gliding.

So lets set up a fair comparison. 10 sheets of EPS foam, cut to the standard size that I use for both Baby Bugs and big Mama Bugs (219 mm by 96 mm) weigh 1.3 grams (Ultra Time Warp) or 2 grams (Time Warp). 10 sheets of printer paper cut to exactly the same size weigh 16.6 grams. That's more than 8 time heavier than even the heavier foam.! Furthermore, the foam is much stronger. Holding the end of a piece of foam so that it sticks out horizontally like a diving board, foam bends just a little bit. But paper cannot hold itself rigid at all. You can say that all you have to do is fold/bend the paper so as to increase its rigidity, and many people have done just that: developing clever designs to maximize the strength of paper with folds. But in the end, paper walkalong gliders are far heavier, much more difficult to trim (adjust) and they fly so fast that it takes hours for newbies to be able to fly. And that doesn't take into account the fact that paper becomes even more limp and useless in all but the lowest humidity air.
10 sheets of thin-cut EPS foam weigh only a couple of grams, and the foam is still more rigid than the paper

I started with paper gliders because I did not know about thin foam gliders. It was frustrating to try to teach my students how to fly walkalong gliders. It took a long time and many students never got it. It only worked in winter when the air was very dry. When I started using foam, I could get everybody flying. Some kids still worked harder and excelled more than other students, but everybody got into the air. I have not worked with paper gliders for years, and I don't miss it.

Measuring foam density

Density is weight divided by the volume (length x width x height) of the foam block. In North America it is expressed as pounds and feet, but I (and the rest of the world) prefer metric kilograms per cubic meter. You can easily convert to pounds/foot if you need to.

I use a triple beam balance to measure weight but you could use a postage scale. I express 6 grams as .006 of a kilogram in my equations; 22 cm as .22 of a meter; 95 mm as .095 or a meter, etc.

Foam Store is Open

These are exciting times! On one hand our foam sheets are much better than ever before: 45% thicker without any added weight. The sheets and gliders are still thin, but it's not like handling soap bubbles anymore! On the other hand, the instructions for making the gliders have not kept up. Better directions are in the pipeline. So if you have flight experience or are a repeat customer, I think you'll love the new foam sheets for making gliders. If you are new to flight, then you might want to stick to ready-to-fly gliders--which are better than ever--until I can finish the new instructions. GOOD CHANGES COMING SOON!

Teaching Groups to Fly with Air Surf (Walkalong) Gliders Original

Does it seem like I'm trying to get someone elected? Actually, the election signs are old, but they make great air deflectors: large, lightweight and durable. Pizza boxes and other pieces of cardboard also work well.

So you've seen a video of air-surfing, AKA walkalong gliding. It looks really cool and you're thinking how much you'd like to do it with your school students/ scouts/ camp/ learning festival or homeschool group. But you want to know what you're getting into. You want some details, like what age groups will it work with, how to start, how much time and space are needed, how to prepare, etc. You've come to the right place. For the past 8 years I've been happily obsessed with walkalong gliders. I've taught lots of people how to fly in schools, science museums and events; learn from my experience (translation: learn from my mistakes)!

Consider trying simple paper walkalong gliders first ("free and frustrating").


Paper gliders are easy to make and a complete pain in the neck to adjust, launch and fly--but worth the effort!

From my own experience and from years of getting feedback from people, I noticed something: groups who struggle with paper gliders first tend to do exceptionally well when they switch to foam gliders. And I do mean “struggle”! Paper gliders are much heavier and difficult to launch. The bend angle has to be just so. Expect moaning and gnashing of teeth. But they seem to gain something by trying (hmmm, sounds like a metaphor for life). Furthermore, newbies wreck gliders with their nervous fingers and general carelessness. But with paper gliders it doesn’t matter! They are quick, easy to make and cost essentially nothing. If YouTube is blocked at your school, you can still view this compressed video instructions. The video starts with lauching the gliders up in helicopters, but there are also instructions for flying them as walkalong gliders. Here is the transcript of the narration, plus some additional details.

Emphasize to the group that the foam/gliders are very delicate.

All other challenges can be corrected, but if a kid mangles their foam glider, it is difficult to repair (see start with paper, just above). The Achilles heel of light foam gliders is their fragility. Kids, and even adults, do not naturally show the amount of care that is needed. Then imagine that you are a kid in a group of peers, and that you are about to try a new physical activity where you might look awkward, and somebody might laugh at you. They get NERVOUS HANDS, clenching anything they hold with a death grip!

Without some forewarning, a group will have the gliders in shreds in minutes. I say things like, "It's like having a pet butterfly". I tell them to always be aware of what their hands are doing and relate how I have the same problem. I tell them about how careful they have to be before they actually handle the gliders and continue to remind them throughout the session.

Feeling how to fly is better than being told.

I could yap on and on with flying tips: keep the deflecting board more vertical like a wall, keep the glider high on the board; don't let the glider get ahead; gain altitude and steer...nobody can keep so many things in mind at once! I have learned that teaching how to fly is best done tactile-kinesthetically. My most effective teaching is walking next to people--whether it is little kids, teenagers or adults. I tell them that we will both hold onto the board but let me actually control it. I launch the glider, since that's yet another thing to think about. After flying together for a bit I say, "It's all yours" and let them take over. I observe how they crash it. Did they steer it into the wall? Did the glider just slowly keep losing altitude? Did they flatten the board instead of keeping it sloped? Whatever the problem is, I walk with them again. I do a little of whatever they did wrong, then correct it and again hand it off. After a few such walks many people are flying well in minutes--not because they understand or remember all the tips, but because they are gaining an unspoken feel for flying. Of course, this means that you have to learn how to fly ahead of time. I urge you to do this anyway. Someone in the room should actually know how to fly walkalong gliders; it will save a lot of frustration.

Teaching people to fly walkalong gliders is easier than actually building the gliders. Teaching people to fly, but not build, might be better at some events.

I love to make things, and I love to set up teaching situations where people are making things. And I have bent over backwards (an idiom) making written instructions and video about how to make walkalong gliders. However, from experience I know that there are some situations where teaching a group of people to fly with already-made gliders works better than making gliders. If you don't have much time, (perhaps 1 1/2 hours) think twice before getting yourself into a situation where you are frantically trying to finish. That will just lead to chaos. Another thing to think about is the age of the group. Many kids starting at age 10 or so have acquired the hand/eye coordination to fly gliders. But I would not make the gliders with a group unless they were at least teenagers (and even many teenagers have difficulty following directions). It's a different dynamic when you are working with just a few people, but this article is about working with groups.

If you are not sure, consider this possibility: Perhaps you can set up one event where you just teach the group how to fly. Then, if that goes well, you can have another event where they make the gliders. You will have had a chance to get to know your group. Were they gentle with the delicate foam gliders when flying? If not, constructing is going to be even more difficult.

In my opinion, kids under the age of 9 or 10 do not usually have the coordination to fly solo.. ... but if they let you copilot then they can still enjoy flying. At the same event the Boy Scouts were teaching mall-goers how to fly after I taught them.

Even if you do decide for the group to actually make the gliders, have your group fly some gliders first. Make them only after they have flown. Have some gliders ready to go.

I know that sounds backward. You would think that it makes more sense to make, then fly, right? I did it that way for years. Here's why I switched.

Flying is easier than making. When you fly first, then building gliders makes more sense. Even if people have experience with origami, there are many parts of constructing the gliders that are counterintuitive. But if they fly the glider and see how the glider is made, then they are less likely to make a mistake when building. Instead of one giant step (building and flying), you break it down into two easier steps--flying, which is easier; then building, which is made easier by the first step of flying.

Practice flying before the event.

I know, we're all busy, but I think it's a good idea for people to know what they are doing before teaching others. Maybe that is obvious, but I often see people try to figure it out at the same time people are depending on them for direction. If you are making gliders with the group, make a couple of gliders before.

I can think of a possible exception to the "practice ahead" rule. If you are working with a group of sharp high school or college students--and you know that they can follow instructions--then they might be able to figure it out themselves with the video or written/ illustrated instructions. But I think middle school and younger students will need more of your guidance.

Consider the ratio of students to you, the teacher.

When I hear from someone who is very enthusiastic but does not have much teaching experience; and they tell me that they plan to get 30 kids making and flying gliders, I see disaster ahead. It is not even enough to have some other helpers in the room. In my opinion, they have to be helpers who have practiced ahead of time, just as you have.

But once you know that, amazing things are possible! I got some wonderful feedback from Shannon Babb with Utah State University Extension and STEM coordination with Utah County 4-H. Through teamwork, Shannon reported that they got nearly a thousand people flying.

"Oh my goodness, the event went so well. The teens had so much fun learning how to make the gliders and caught on so quickly, that they wanted to teach some of the younger youth how to fly gliders at the aviation event that was open to all ages later that evening. I will admit I was a bit nervous about doing the activity with a young age group, but the high schoolers really stepped it up and worked one on one with the younger kids. By the end of the evening, everyone was thrilled to have interacted with the gliders whether they had the skill to figure out how to fly them or not.

"Now that we have an experienced teen volunteer base that are interested in teaching all ages how to fly, and older youth and adults know how to build the gliders, I have a feeling that they are going to worm their way into a lot of future activities.

"Honestly if the teens hadn't taken charge there is no way that the walk-along glider activity would have worked without their leadership."

Be aware of the psychology of your group. Some adolescents are terrified of being in situations where they might look stupid.

Most of the time I see nothing but unbridled enthusiasm when I am teaching people to fly. However, air-surfing gliders is a physical activity, and a very new physical activity at that. Like all new things, sometimes we look a bit awkward and silly until we get it. I find that at about 13 or 14 years of age, some kids become very extremely selfconcious when they are in groups, and this can be a very destructive group dynamic when trying to get them to do something new. When adolescents feel vulnerable to judgment or teasing, some shut down and stop trying. Obviously, you will want to create an emotionally safe atmosphere and nail teasing before it starts.

Some people will disagree with me about this next tip, but I also try to start with low expectations. I tell them that it took me days to learn air-surfing (true) and that I don't expect them to be able to do it in just one day. So if they don't get it, they retain some dignity. If they do get it, then they are quite happy (and sometimes you see the other side of insecurity: obnoxious bragging). So maybe you won't use my methods; but do be mindful that with some age groups, psychology can be a force to be reckoned with.

Think about the space your group will need for flying. Be mindful of air turbulence (take note summer camps).

I do not live in a very windy region but, except at dawn and dusk or certain completely overcast days, it's impossible to air-surf outside. The very slightest breeze that you can barely feel on your face is too much. That does not mean that you need a gymnasium. With the very low-density foam I call Time Warp, the gliders fly slowly and are maneuverable even in small rooms. And for larger groups, the wide halls, lobby, cafeteria and auditoriums in public buildings work well. But, always scout out the location first. Many science museums and even some schools have aggressive ventilation systems. Be sure that there are calm places with still air, or else flight will be impossible.

Encourage your group to spread out.

Kids are very social, and they often clump together even when there is enough space. But it can be a problem even if they are not actually colliding. People moving through the air create air turbulence. Try flying a glider walking behind someone walking a few feet ahead of you. It's impossible because air swirls behind people in turbulent, circular vortices.


Links

This article is about flying walkalong gliders, and that opens up teaching moments about flight.

  • Walkalong gliders stay in the air the same way that hang gliders can stay up for hours; by flying in rising air. Although this video is about hang gliders, much of it applies to walkalong gliders.
  • I am starting to hear of people who are using walkalong flight as an analog for piloting, particularly cadets in CAP (Civil Air Patrol). It's a great way to get a feel for takeoff, flight patterns, turbulence, approach and landing. This is an old but still good video about aerodynamics and piloting.
  • Once people get a feel for flying, some will experiment with their own designs. One popular branch is bio-mimicry.
  • Like all good science discovery stories, walkalong gliding history is full of people with unconventional ways of looking at the world, catastrophic and fortuitous accidents, serendipitous insights, cross-pollination, community and collaboration. You can see interviews with the historical innovators here. And a little farther down the page you can see links to You Tube videos of other people doing interesting things with walkalong gliders.

Thanks for taking the time to show others how to fly. Please let me know of your successes and challenges. I don't have all the answers. If you have tips that worked for teaching with a group, share them.

Slater Harrison aka SciencetoyMaker

Make Dihedral Magnus Effect Gliders for Walkalong Flight and Payloading

 

If YouTube is blocked at your school, you can view this compressed Quicktime movie (30MB)

The embedded video above is about making and flying a simple kind of glider, or sending it hight up in helicopters.

Below is the transcript of the narration, plus some additional details. The numbers are time markers that tell you where to go in the video to see it. If you have a question, you can leave a message in the comments section at the bottom of this page or contact me about it and I’ll try to answer it on this page.

Although I have tried to be very forthright about saying that these paper gliders are harder to fly as walkalong gliders than thin foam gliders, I still think it's a good idea to start with paper gliders. It might be a struggle with lots of frustration, but it's a worthwhile struggle nevertheless. I've observed that groups that start with paper gliders do very well when they move to foam gliders. Maybe it's because newbies tend to crush gliders with their careless or nervous hands. But it's so fast and easy--and essentially free--to make new paper gliders as needed. Whatever the reason, it's a good idea to try flying paper gliders first; the effort won't be wasted!


0:00
Hi I’m Slater aka sciencetoymaker. These strips of paper tucked away in the helicopter: do they look like gliders? Let’s try them out in the Troposphere! When you become fascinated by things that fly, then you become aware that we live at the bottom of an ocean of air called the Troposphere. Here’s a good page about that.

And it’s even possible to fly this strange glider inside on a deflected wave of air.

An example of dihedral

0:35
The name, Dihedral Magnus Effect glider, is long, but it’s quick and easy to build.
But first, dihedral is the slight upward bend of airplane wings for better flight stability.  Without dihedral, the glider slips sideways. Then the Magnus effect is what makes spinning soccer balls curve as if by magic. Physics Girl did a stellar job of explaining the Magnus Effect in this video.

Even when  the glider is traveling so slowly that it seems like it ought to stall and dive out of the air, the Magnus Effect keeps giving it… almost magical lift.

1:10
And when I fly the Dihedral Magnus Effect glider like this, it’s called walkalong gliding. The upwardly deflected air lifts the glider up as much as gravity pulls it down—similar to the way hang gliders can stay in updrafts for hours, not just glide.

I don’t want to oversell these. Although Magnus gliders are easy to make and launch in a helicopter, the trade off is that they are not very efficient; and paper is actually quite heavy. So they’re difficult to launch and fly.  Fixed-wing walkalong gliders made of 0.7 millimeter foam are easier to fly.  But hey, paper’s here and free, so let’s make a glider now.

1:57
To start you’ll need some telephone book paper. Newspaper is a little heavier still, but newspaper can be ok too. Now here’s something interesting: all machine-made paper has a grain, so paper is much stronger one way than the other. I’ve cut two rectangles out of one phone book page; identical except that one is parallel to the text while the other one is long perpendicular to text. When you cantilever them off an edge, this one is clearly more rigid so we’ll cut strips parallel to the text. But test your assumptions! This small newspaper is strong parallel to the text; but this large newspaper is the opposite!

2:43
The strips should be about 25 mm wide by 155 mm long (1 inch by 6 inches).  To get the dihedral, you fold gently in half.  Folding in half before cutting means less cutting.  It also insures symmetrical halves, so it will glide better. You can save a lot at a time by folding and cutting lots of gliders at once.

3:11
You might be able to launch the glider now, but another fold will make it stronger. Origami people say that this is a valley fold. Make a gentle mountain fold perpendicular to the first fold, then mostly unbend it. That hint of a fold makes it less floppy and creates a crude airfoil that helps the glide a little.

If you have too much dihedral angle, then it will not fly. Just a little.

3:39
If you are sending gliders up as a payload in a helicopter, slide 3 or 4 under the rubber band at the bottom. The rubber band ejects them as it unwinds.  See this link to learn more about how to launch gliders.

4:01
For walkalong gliding, you need dead-calm air. That usually means inside, away from air vents. I’ve been in many science museums where it was all but impossible to fly because of air turbulence. However, usually I was able to find a hallway or something where the air was still enough to fly.

If you want to try walkalong gliding, your first hurdle is launching. Your glider should glide away from you, not toward you. Hold the glider from the back like this. There is only a slight dihedral.  Give a short push—really just a tiny flick of the wrist--and let go. You can also try launching like this. Practice launches and when 2 out of 3 glide straight, then you’re ready to fly. Experiment with dihedral angle.

4:38
The bigger your board is, the better. The top of a pizza box works well.  Hold the board almost vertical. It has slant a lot to deflect air upward. Launch high. Keep the glider level with the top of the board. Keep the board so close to the glider that it almost blows over the top.

5:05
To gain altitude, make the top of the board go so close that the glider goes over the top. Notice how it went higher just before going over. So this time, raise the board so the glider can’t go over; it gains altitude instead. Try pulses of getting closer to see where the sweet spot is.

5:35
You turn by pushing one side of the board closer to one side of the glider. You cannot make sharp turns with this glider and fast moves don’t work.  Keep your board smooth and steady.

5:50
I learned to fly with a similar Magnus glider and I struggled for weeks before getting it. It takes even longer for the pioneers who charge ahead without anyone to show you how to fly. Flying the glider is like riding a bike: it takes time and practice to learn, then gets easier.

6:23
Let’s tip our hats to John Collins, AKA the Paper Airplane Guy, for inventing the first Magnus Effect paper glider, which he calls the Tumbling Wing.

6:35
Very humid air makes paper limp and useless

Dihedral Magnus Effect gliders made from thin slices of foam are not affected by humidity; and they are so light that they fly slowly. In fact, I can fly them with just my hands deflecting the air. You can have a single piece of North American standard foam from sciencetoymaker.org, cut it in half and sliced into 13mm or ½ inch strips. They’re very easy to make but are still tricky to launch. Foam fixed-wing gliders are easier to launch but harder to make. Life is full of tradeoffs.

7:09
Besides being delicate—you need to handle them very gently--the foam gliders are even more sensitive to how much dihedral you have. If the glider seems to slide or it keeps tipping over like this, then you need more dihedral. If the glider is clunky or won’t glide at all, then less dihedral. There’s not much difference between too much and not enough, so you’ll have to experiment

7:39
Fixed-wing foam gliders are easier to launch and fly but harder to make. You can learn about foam gliders here and buy thin foam sheets here.


Welcome to Air Surfing!

(AKA Walkalong Gliding)

"Any sufficiently advanced technology is indistinguishable from magic." --Arthur C. Clarke

If YouTube is blocked at your school, try this 16MB MPEG file

How to Start Flying Any Design of Glider

Introduction to Walkalong Glider

The first time I encountered gliders levitated and controlled by an invisible wave of deflected air, it felt like magic! Surely this was going to take the world by storm, the way Mentos and Soda swept the world as a science activity a few years ago. But while researching the history of walkalong gliders, I was surprised to learn that the concept of surfing the gliders is decades old. Knowledge about them was cloistered within a few aerospace engineering and hang glider communities—definitely not in schools.

As an educator, I set about to make walkalong gliders accessible to regular people as a fun science activity by developing thin (1/2 mm) foam gliders that are an order of magnitude lighter than paper. Only a few times denser than air itself, they fly so slowly that beginners have time to think and react. If I walked beside you and we both held onto the board, then you could learn to fly in minutes because that way you gain a feel for flying. Soon you would be swooping around your house flying as easily as you ride a bicycle.

And the thin foam gliders are so efficient that advanced pilots (with practice) can levitate them with only their hands deflecting the air! The foam sheets are inexpensive to buy or slice your own--no one is excluded for lack of money. I find that kids around the age of 10 start having enough coordination to fly them.

So NOW the activity is going to catch fire, right? No. Any knucklehead can drop Mentos in soda, but walkalong gliders demand more. You don’t need to be flight savvy to start, but you have to pay attention to details. For one thing, the thin, light foam is also very delicate. The gliders won’t break from crashing into walls, but careless/nervous hands will wreck them in seconds. Even adults lack an analog for handling something that carefully--unless they’ve cuddled with a pet butterfly. Furthermore, the gliders need dead-still air, which usually means not outside except at dawn and dusk. Even aggressive HVAC systems and cause too much air turbulence inside. And although I can easily show people how to fly, being the first in your region with nobody to show you is more difficult.

Some people will be daunted by these eccentricities of walkalong gliders. But inspired pioneers--who care a little more about details and work a little harder to learn new things--are spreading walkalong flight in the world! Here are some tips for teaching groups to fly.

 Learn to Fly Walkalong Gliders

Flying an already-made glider is the best way to begin and all packages come with a couple of RTF (ready to fly) gliders. This video shows the best way I know of how to learn.

Teaching a group to fly? Here are some tips.

 Get Gliders and Foam Sheets

Using gliders made from thin, low-density EPS (expanded polystyrene) is the best way to get started. Foam is extremely lightweight and slow-flying, so you have time to think and react. Thin sheets of EPS foam are much lighter and more rigid than paper, and inexpensive, too. Get gliders and foam here.