Birdy paper
Birdy paper
glider
glider By Jose German Tapia
Building a catapult glider doesn’t have to be complex or expensive!
PHOTOGRAPHY: JOSE GERMAN TAPIA I
always have been mesmerized by (nat- ural or man-made) gliders, perhaps because, by their own nature, they represent the purest form of flight.
Now adays, model gliders have evolved from the old time stick and tissue flyer to the use of high-tech electronics and com- posite materials.
I am not at all a model airplane guru, but rather an enthusiast. I have been building pa- per gliders for a while, the type designed by Y. Ninomiya, T. Yoshida, E.H. Mathews, and others, from whom I got some ideas and hints. Tired of buying special materials, taking one week to build and one minute to crash, my idea was to do exactly the opposite: to build a glider using only the most common materials, available anywhere and anytime; that is, paper and white glue, at a minimal cost, of minimal construction time, and yet with decent glide characteristics. The only building tools would be scissors, ruler and a ballpoint pen for scoring, for building a glid- er coming out straight from the printer or photocopier.
I went minimalist; I didn’t want to resort
to the use of balsa for the fuselage, paper clips or coins as nose ballast or numerous paper nose cones. I wanted to make a lami- nated paper glider using just paper, and not even different types (I had tried that also), but a single kind of paper for the entire plane in order to maximize simplicity. And there I had my first quest.
32 The paper
I started with a simple laminated paper glider design which (after multiple modifica- tions) was the base for the final glider. Thinking on easily replicating the glider, one limitation I imposed on myself was that any piece or part of the plane had to fit within the limits of a letter size sheet, that is, 11 × 8½ inches, and even more, within the limits of a photocopy area, which is about one centime- ter (1⁄4 inch) less at every side around. I started by using 90-gram per square me- ter or 90 g/m2 (25-pound) paper, a bit stur- dier than the regular paper of 75 grams (20- pound) used all around for copying and printing. It was certainly light, but it was also too flimsy. Things were not much better when using 120-gram paper. I kept on try- ing different thicknesses (up to cardboard) and finally the best compromise between strength and weight was the white 176 g/m2 (65-pound) cardstock.
About a dozen gliders later, I stumbled on a pack of colored 175-gram Wausau card- stock, and I decided to give it a try. To my surprise, the colored paper turned out to be more firm than the white one. This was then the obvious choice, offering the additional appeal of rendering a multicolored glider. From there the name Birdy.
The parts
We all know cardstock is a heavy material for gliders. In the quest for the proverbial
AT A GLANCE Type:
Construction: Wing span: Wing area: Length: Weight:
Wing loading: F/F glider
Wausau cardstock 10 inches
16.66 sq. in. 7.875 inches .25 ounces .426 g./
sq.in.
wing load ratio of 0.5 grams per square inch or smaller used in balsa gliders, I thought it sensible to make the biggest wing possible within the area of the paper.
The wing, which is the largest component in a glider, could not be longer than 12 inches if you position it diagonally in the page. True to my own rules, I would not have the wing in two parts and glue them together. At the end, all the glider parts fit on two sheets. The wing required a reinforcement glued on its top for it not to bend upward with the wind force when catapulted. For the sake of simplicity, the reinforcement had to be an integral part of the wing, which obliged a partially straight leading edge as folding “hinge” for the reinforcement; that is, a semi-elliptical wing.
April 2013
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