I can’t believe how much of my past weekend was absorbed with super thin pieces of styrofoam foating oh-so-magically through the air. I have been a Radio Control (RC) nerd for over 15 years now (thanks, Dad!), but I believe I may have found the highest bang:buck ratio in all things flight:  Walk-Along Gliders

walkalong glider

Notice 5 bends: 2 elevons (in the rear), 2 cambers (front/leading edge) and dihedral (in the middle). Thin wire attached to the front for adjusting center of gravity.

The key to these little gliders is their incredibly light weight.  Paper is way too heavy!   And even the thinnest commercially-available styrofoam is 10x too thick.  So, you’ve got to either buy custom-sliced foam from a really talented tech teacher named Slater Harrison in the USA, or make it yourself.

All flying machines require lift in order to counteract the downward force of gravity.  Airplanes do this by utilizing an airfoil, which, when moved through a fluid such as air, provide a differential in pressure (low pressure above the wing).  This results in a net upward force.   The key is that the wing must be moving relative to the air–and to do that, thrust is needed.

Engine-powered gliders obtain thrust from the engine.   By definition, gliders don’t have his luxury.  Once the glider has been towed or winched into the sky, it’s only ability to generate thrust is by converting the potential energy that it has accumulated into kinetic energy as it glides downward, trading height for distance.

Glider forces

Thanks to Slater Harrison for this illustration and his fantastic website

Walk-Along Gliders refer to a class of aircraft that rely on the ‘pilot’ to provide a steady stream of rising air, which keeps the aircraft aloft. Essentially, they are operating on the same principle that allow paragliders to stay up indefinitely  (assuming favorable winds), but instead of finding natural updrafts, the “pilot’ creates one by pushing a large, rigid board through the air. When air hits the board, it is forced to divert around/above/below it, and by angling the board slightly backward, most of the air rises. A very light, carefully trimmed aircraft can essentially surf the wave of higher pressure air that is being forced upward.

Thanks to Slater Harrison’s very informative website:   http://www.sciencetoymaker.org/airsurf/index.htm You will find lots of support to build these contraptions.   Patterns, detailed build videos, and even crystal-clear instructions on how to build your own wire-cutting contraption (which worked perfectly!)

Mosquito glider plans

Mosquito Pattern

Mama Bug glider plans

MamaBugPattern

Here is how you can create super-thin slices of foam from whatever blocks of styrofoam you can scrounge up.

My home-made wire hot-wire-cutter.

My home-made wire hot-wire-cutter.  Rubber bands keep the wire under a moderate amount of tension.

IMG_0483

Thin is key!

Regular polystyrene (i.e.

Regular polystyrene (i.e. “Beer cooler foam”) can be turned into magically-thin slices.