Free Flight Sport - 2009/09

THE HEYDAY OF model aviation was in
the 10 years after Charles Lindbergh’s
historic crossing of the Atlantic Ocean via
aircraft in 1927. Tens of thousands of youth
built and flew model airplanes, and many
groups were developed to organize modelers
and promote model aviation.
One of those organizations was the
Junior Birdmen of America, which the
Hearst newspaper company sponsored.
There are many interesting photos of Junior
Birdmen memorabilia, as well as a brief
history of the organization, online. The Web
site address is in the “Sources” list at the end
of this column.
Cellulose-based glues have been the
mainstay of modeling for 80 years. They still
have their place. Three of the most common
brands currently available are Duco
household cement, Ambroid, and Sig-Ment.
Duco is generally available in hardware and
craft stores, Ambroid is available at some
hobby shops and A2Z Corp, and Sig
Manufacturing sells Sig-Ment.
As they come from the tube, most of these
glues are a bit too thick for our use. Many
modelers put the adhesive in an applicator
bottle (available from A2Z Corp) and thin it
roughly half with acetone. (That’s the way I
use it.) The blunt needle applicator on the
bottle allows good control, so you can put the
right amount of glue in the right spot.
These adhesives work better with double
gluing. Put a small amount on both sides of
the joint. Let it dry for a few minutes, reapply
a small amount to both sides of the joint, and
put the pieces together. The key to a strong
seam is having no gaps and using the least
amount of glue needed to do the job.
The cellulose types have several
advantages. They are extremely lightweight,
they give the builder a little time to get the
pieces in the right places before they set, and
the joints can be released with acetone if parts
need to be repositioned.
The lightweight characteristic is crucial
for building indoor models. When setting up
my scale aircraft, I like to tack-glue the
stabilizers in place for the flight-trimming
process, in case the stabilizer incidence has to
be changed.
Cellulose glues’ disadvantages are that
they take a bit of time to set up and that they
have a slight smell. You can minimize the
setup time by using the double-gluing method
and using no more adhesive than absolutely
necessary.
My current favorite glue for framing
stick-and-tissue models is Titebond II. Do not
apply it directly from the bottle. Dispense a
small puddle onto a handy corner of your
plans’ waxed paper covering and use a craft
pick or scrap-balsa stick to apply a minute
amount to both sides of the joint to be glued.
You can thin the adhesive 50/50 with water
or alcohol if you want.
As when using cellulose glues, it is
especially important that you double-glue
end-grain joints. Titebond will quickly soak
into the end grain, and there will not be
enough glue for a strong joint.
For crossmembers with end grain, dip the
end of the stick in the Titebond. Touch it to
the fuselage frame and wipe off excess glue
from both parts, but do not put them together.
Let the adhesive dry while you fit the next
crossmember. Within a minute, you can
reapply the Titebond to the crossmember and
fuselage frame, and put the piece in place. If
you have used thin layers of glue, the bond
will set quickly. It is fast, but you still have
time to adjust the part’s position.
The advantages of Titebond II are that it is
odorless, inexpensive, sets reasonably
quickly, and is easy to sand. I find it
especially useful for making wingtip and tailfeather
laminations.
One disadvantage is that it is watersoluble.
A couple of my models have had the
misfortune of landing in a puddle or spending
overnight in dew, and the laminations came
apart. That takes time to happen, so it’s rarely
a problem.
Sometimes I use medium CA when I am
in a hurry. Again, I place a small puddle on
the waxed paper, dip the end of the
crossmember in the glue, and put the
crossmember in place. Pregluing is
unnecessary; it is counterproductive.
Apply the adhesive to one side of the joint,
and put the pieces together. Do it perfectly;
there is little room for error. Adjustments need
to be made quickly.
If I need to apply a small amount of CA to
a part that I can’t “dip,” I use an applicator: a
2-inch-long triangle of waxed paper. I touch
the tip of the triangle against the puddle of CA
and apply the small amount it picks up to the
model.
Again, less glue is better. Use the smallest
amount you can to get a bond.
Thin CA wicks quickly into the balsa and
travels, or runs, along spars, so it can be a
problem. Even the smallest of applicator tubes
that can apply a single drop provide too much
glue for a typical stick-and-tissue model joint.
It is difficult to “reglue” a poor joint, because
CA doesn’t stick to itself too well.
Good joints are almost impossible to adjust,
because the wood will break before the joint. It
won’t bond well if there is a gap in the joint.
Thin CA is great for instant repairs.
I protect my plans with waxed paper. I have
heard complaints that waxed paper “ain’t like
it used to be.” However, I suspect that those
who are having trouble with its sticking to
balsa are using too much glue or thin CA. I
have tried parchment paper but can’t see
through it as well as I can see through
waxed paper.
Farrel’s Skyraider: Wally Farrel has been
flying his 19-inch-wingspan Skyraider for
many years. He built it from Tom Nallen
plans from Flying Aces Club (FAC) plans
packet 5. They were published in the May
2009 FAC newsletter.
The Skyraider has placed five times in
its last seven meets, with three firsts and
two seconds. It got a new wing after an
unfortunate crash at Geneseo, New York.
The model flies on two loops of 1/8-inchwide
rubber that are roughly 30 inches long,
turning an 8-inch Peck-Polymers propeller.
The flight pattern is usually left under
power and right glide. Wally has noticed
that when he uses larger propellers, models
tend to turn into a right-hand glide.
The lion on the side was carefully cut
from a computer-printed copy. The finish is
airbrushed acrylic paint. The aircraft’s
empty weight is 26.5 grams.
You can become a member of the FAC,
which includes the bimonthly newsletter,
for $18 in the US or $25 in Canada. In
addition to club news, each newsletter
includes three or four sets of plans—usually
for scale models.
George White built his 22-inch-span Mike
Midkiff-designed Fokker D.VII from the
RockyTop Models kit. According to
George, the kit is extremely well done.