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TIPS |
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TIPS |
HOW FLAGS FLY
This
article is written as an addendum to "COMPUTER GENERATED FLAGS" (6
"TIPS" back in the list), which describes making flags out of
Kleenex using a computer's printer. I tried several other types of paper (including onion skin
and rice paper) and found only two others that were as thin as Kleenex.
Those were gift wrap tissue and Silk Span, a paper used to cover flying
model airplane balsa framework. The
covering was then tightened using "dope" paint to shrink the Silk
Span. All three papers were measured with a micrometer and found to
be .001 7 in. thick. A bleeding
problem occurred with all three papers in my ink jet printer. It was solved somewhat by adjusting the printer
cartridge/paper distance. More
tests need to be run to find the optimum setting and this may be different for
each ink jet printer. Over all, the
Silk Span seems to give the best results thus far, although it is stiffer than
Kleenex.
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To stiffen the flag I used what I
had available, a clear matte Rust-oleum spray.
I sprayed the flag until fairly wet then created the desired shape with
my fingers and different sized drills to form folds.
The matte spray I used was tacky, making it difficult to manipulate the
flag. Out of curiosity, I also
tried water soluble matte medium. Since
the ink jet's ink is water soluble this approach completely smeared the flag's
colors. Thus a matte (not shiny)
spray lacquer must be used as the flag stiffener.
I'll try some other artist's matte sprays and report the results later.
Now I'd like to get into the main
subject of this article. Just how
do flags fly, i.e. what shape do flags take in the wind and why do they take
that shape? In considering this
question I discovered something that others probably knew.
All flags normally attached to a lanyard on a vertical (or near vertical
) Flagstaff will assume a certain changing pattern of folds relative to wind
velocity giving them a fairly consistent appearance. There is a reason for this consistency.
For a significant portion of a
flag's displayed life the flag experiences no wind and is in a drooped
appearance. To describe this in
more detail, assume the Flagstaff is on the left with the flag (if held out
straight) projecting to the right. As
the flag 'droops", the upper left corner is at the apex with the rest of
the flag draped naturally down from that corner into several narrow
"cones" (folds) with the cones' apex at the top corner and the round
"base" of the cones at different levels near the bottom (FIG. 1) .
These cone-shaped folds are set into the flag by the weather, i.e. soaked by
rain then dried by the sun, etc., so that as a breeze starts occurring, the
flag's folds start gradually moving to the right and upward.
As these folds are moved by the wind they take an appearance of slanting
from the upper left hand corner downward to the right at various angles. As the winds picks up, the folds undulate and shift somewhat
but they always take the direction from the upper left corner down to the right.
If there is only a slight breeze, the bottom left portion of the flag
will start to straighten out with the upper right portion remaining somewhat
folded together (FIG. 2). As the
wind stiffens, the remaining folds will start opening up and "flap"
back and forth. As the wind
velocity gets still higher, all the folds start to become visible, undulating
along the flag. However, even in a
hard wind, the undulating folds will still show a pattern from upper left to
lower right (FIG. 3).
By now one might raise the
question "Isn't this getting a little nitpicky"?
I suppose, in a way, it is. However,
have you ever looked at a flag on a model and commented "That just doesn't
look realistic. It looks more like
a toy" . Ever since I was a kid I've been fascinated by "miniature
realism", models that were so realistic that you couldn't tell if the
photograph was of a model or the "real thing".
So, when I make a model, I try, as far as possible, to make everything to
scale and as realistic as I can. Flags,
on many of the models I've seen, are not to scale (in thickness) and do not look
realistic. That's why I'm excited
about Bill's technique that allows us to make accurate, scale flags.
