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Old Sep 08, 2012, 02:01 PM
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Originally Posted by Edmond Hui View Post
I'll give you that. Or even at transonic speeds.
The dart design would do better with JATO. Each design has its advantages.
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Old Sep 08, 2012, 02:05 PM
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Originally Posted by Edmond Hui View Post
I've just today received some foam sheets from Slater and will be experimenting with those. I did see Tyler's TED talk when it was first put on the TED site. It was the first time I'd seen walkalong gliding.
It would be a natural to finish your next Paperang presentation with a walkalong glider flight of the slower flying paperang made with lighter material (and proportionally lighter ballast). Is there any other way of continuous propulsion of such a light design? We use forward pointing boom ballasts to further reduce the weight. With the Paperang you might have a small piece of tape instead of a staple and use a thin tie-wrap (wire) pointing forward of the nose as Slater does in his video (at 4 minutes and 25 seconds into the video):
Part 4 Air Surfing Kit (9 min 12 sec)
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Old Sep 08, 2012, 11:11 PM
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When I demonstrate the Paperang, I always have to ask the little kids to pick it up by the centre, otherwise they always grab a wingtip and bend it. They seem to have no concept that something I make to millimetre accuracy might work differently if they put a centimetre bend in it!
Sliced foam is amazing as a light weight and miraculously durable material. To get back to your point of using nonstandard materials (yes?), I just made a tumblewing out of a plastic shopping sack. It is hard to work with but holds its shape because of the folds and because it doesn't weigh anything. Blow too hard and it will crumple. I'll try and put together some data of the weight per unit area of the plastic films I scrounge up while shopping or in my hotel room. I'm always thinking back to the butterflies which skillfully evade danger rather than rely on durability for survival. And you can never be durable enough, armadillos don't even fly and they are becoming scarce because their strategy of rolling up into a ball is no match for a speeding car. So what you'd think wouldn't work because it appears to have no strength might just hold together and fly!
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Old Sep 09, 2012, 10:41 PM
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Originally Posted by x-surfer View Post
To get back to your point of using nonstandard materials (yes?), I just made a tumblewing out of a plastic shopping sack. It is hard to work with but holds its shape because of the folds and because it doesn't weigh anything. Blow too hard and it will crumple.
Plastic shopping bags (specifically the cheap, thin PET plastic) can even be held aloft by static electricity. I haven't tried it myself but this looks cool:

Walkalong Glider Goes Electric (2 min 42 sec)
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Old Sep 20, 2012, 09:43 PM
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Plastic shopping bags (specifically the cheap, thin PET plastic) can even be held aloft by static electricity. I haven't tried it myself but this looks cool:

http://www.youtube.com/watch?v=1-jRxBfo7cU
Yes, the lighter the materials you use, the easier they are to levitate with the electric field of static electricity between a like charged paddle and object. Then the air is just used to dampen the motion of the supported object. Walkalong glider pilots I know also play with static. It takes a keen sense of the forces involved to tell the difference between aerodynamic walkalong gliding and electrostatic levitation. With static, the object can hover, motionless and is "flown" by being pushed in the center of the paddle instead of the top edge (if the electrostatic force is enough to overcome the aerodynamic drag).
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Old Sep 22, 2012, 09:08 AM
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An even easier static levitation trick is to find a milkweed, dandelion, or thistle fluff, break off the seed, then let it attract to a charged styrofoam board. Shake the board edge-on through the air to let the airflow "roll" the fluff aross the board so it takes the same charge, then watch it jump off and levitate! You can't get any slower or lighter than this, unless you have some aerographite to play with, maybe.

With that said, although levitation is fun, the upper weight limit for statically levitated objects is much less than for aerodynamically supported gliders, given our current methods. My heaviest levitator is maybe 100 mg, whereas the heaviest walkalong glider is around 2 oz (Phil's Jumbo glider, aka "Nuclear Winter")
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Old Sep 22, 2012, 10:55 AM
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An even easier static levitation trick is to find a milkweed, dandelion, or thistle fluff, break off the seed, then let it attract to a charged styrofoam board. Shake the board edge-on through the air to let the airflow "roll" the fluff aross the board so it takes the same charge, then watch it jump off and levitate! You can't get any slower or lighter than this, unless you have some aerographite to play with, maybe.

With that said, although levitation is fun, the upper weight limit for statically levitated objects is much less than for aerodynamically supported gliders, given our current methods. My heaviest levitator is maybe 100 mg, whereas the heaviest walkalong glider is around 2 oz (Phil's Jumbo glider, aka "Nuclear Winter")
That's fascinating that electrostatically levitated objects need to be lighter than aerodynamic soaring supported gliders. Nature always wins with super light geometries which maximize aerodynamic drag for seed dispersal in the lightest wind.
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