Designing Your Own Glider
There are many factors that come in to being when you attempt to design your own
glider. There is the wing shape, the wing size, the wing placement and the tail size. In this section I will attempt to summarize the major points of design so you can
successfully design and build your own glider.
Materials: The materials of a plane are one of the most important factors. Since
this glider we are building is going to be relatively small I recommend a light but
stiff material. Two good choices are high grade balsa wood or heavy oak paper. If
you use the balsa wood it may be necessary to be more concerned with the weight
of your plane. You will also need something to hold the plane together, I found that
model wood glue worked well for balsa wood an plain old glue is fine for paper. It
is important that in construction we don't use to much glue because glue is heavy
and it will weigh down your glider.
Design: The first major step in designing your glider is determining the wings
shape and size. I recommend a simple rectangular wing shape this shape makes for
the easiest calculations later. The wing size and shape also play a major role in
determining the dimensions of the rest of the plane.
The first calculation is for determining the size of the horizontal stabilizer. This
equation is: SH=(1.2) times S(T) divided by DCG.
Now, before you panic let me explain.
SH= The surface area for the horizontal stabilizer(cm. sq.).
S=Main wing surface area (cm. sq.).
T=Chord length of main wing (cm.).
DCG=Distance from center of gravity to the horizontal stabilizer (cm.).
So, basically the horizontal stabilizer is equal to the wing area times the chord
divided by the distance from the center of gravity times 1.2. Now enter your ideal
numbers into this calculation, my guess is that you will find that you tail is to big
for you liking. The best way to fix this is to reduce the length of you cord and make
the wings longer from end to end to preserve enough surface area.
The next step in the design is to determine the size of the vertical stabilizer. This
equation is SV=S times SP divided by DCG times .05.
S and DCG are the same as above.
SP= the wing span
SV=surface area of vertical stabilizers.
The surface area of the vertical stabilizer generally does not pose a problem.
Once you have your numbers and sizes all worked out you can begin
Wings: The wings, once they are cut out must be curved slightly so Bernoulli's
principle can work. After you have them shaped (paper you can just bend, balsa
wood has to be braced in the curved position and left over night) place them on
top of the body so that the center of gravity is about a quarter of the total wing
cord in from the leading edge. Make sure also that the wings have a dihedral of
about 5-15 degrees. The wings should also have a angle of attack of about 2
degrees. After this place the vertical and horizontal stabilizers as your
calculations determine. They should both be flat with no up down or left right
angle in them.
The plane will probably need to be adjusted to fly properly please see control
surfaces for further information.
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