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Building Straight |
‘shop talk
Steve Condon
Building Straight: The
secret to true flight performance
Anyone that's had one knows: crooked
models just never fly right. If you're a relatively new model builder, "pretty
close" may seem fine when you're up late at night and frustrated because you can't
quite get the parts to fit the way they're supposed to—but it's not. In those times,
it's better to stop and get a fresh look at the problem in the next building session.
Square alignment of wings to tail; a
straight fuselage; and the freedom from warps in the flying surfaces makes a significant
difference in the performance your glider will yield. So, how do you insure the model is
built straight? Here are 5 things you should do:
One
Take your time. Sight and check each axis twice before gluing. In short "Measure
Twice, Glue Once."
Take your time. Sight and check each axis twice before gluing. In short "Measure
Twice, Glue Once."
Two
Make sure your building board is straight and flat.
Three
Make sure molded or pre-built parts are not warped. If you sight down a glass fuse and
find a bow or twist, use a heat gun (carefully!) or very hot water (not boiling--150
degrees max) to soften it and carefully move it back to true. Having a second pair of
hands makes this much easier.
Four
Make sure that wings and tail are square. There are two methods: careful measurement, and
"eyeballing" it. I prefer to do a little of both. One thing that is difficult to
measure accurately is the squareness of the stab to the fin because both surfaces
generally have some taper to them.
Make sure that wings and tail are square. There are two methods: careful measurement, and
"eyeballing" it. I prefer to do a little of both. One thing that is difficult to
measure accurately is the squareness of the stab to the fin because both surfaces
generally have some taper to them.
What I have found to work quite well is to
line myself up with some of the cross-members on the inside of my garage door. Holding the
fuselage up at eye-level, line the fin-up with a vertical piece, and the stab with a
horizontal piece. This is a very good reference for the "eyeball method."
Of course, it is a good idea to check that
the cross-members on your garage door are square before you begin.
Five
The "careful measurement" method to ensure that the wing is square to the tail
is also good to perform. First, be sure the fuselage is straight. Then, square the stab to
the fuse by mounting it and measuring from each tip of the stab trailing edge to the
center of the nose. The distance should be the same. A piece of thread fastened to the
nose and pulled taut to the stabs works as well or better than a yardstick and is easier
to work with.
The "careful measurement" method to ensure that the wing is square to the tail
is also good to perform. First, be sure the fuselage is straight. Then, square the stab to
the fuse by mounting it and measuring from each tip of the stab trailing edge to the
center of the nose. The distance should be the same. A piece of thread fastened to the
nose and pulled taut to the stabs works as well or better than a yardstick and is easier
to work with.
Once you are satisfied that the stab is
square, remove it and mount the wings. Use a similar method as described above measuring
from the trailing edge of the wing tips (in the same exact spot on both sides) to the
tail-end of the fuse, or the nose, or both. Measuring to the tail will give you a more
accurate reading.
The most important thing to remember about
building a straight model is to take your time and make sure you get it right the first
time. Before I make any final installation, I make sure that all flying surfaces are true
to the others: vertical stab is perpendicular to horizontal stab; horizontal stab is level
with wings; wings are perpendicular to fuse; and wing tip to stab tip is equidistant for
each side. Only after all these surfaces are aligned do I make a permanent glue joint.
A straight plane takes more time to build but your
patience will be rewarded with true and accurate flight.
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