Great Planes Spectra Electric Sailplane Kit - GPMA0540 - Manual (Page 25)

supplied 1/16" Hex Wrench (WRENCH01). Push the hub
onto the motor shaft until it stops. At this point there should
be at least a 1/16" gap between the spinner backplate and the
nose cap. If there is not enough clearance you can either sand
back the nose cap or you can move the hub out 1/16" on the
shaft (but do not move it out any more than 1/16" from its
"fully on" position). When satisfied with the clearance,
remove the prop assembly until after the plane is covered.
FINAL ASSEMBLY
BALANCE THE AIRPLANE LATERALLY
SPECIAL NOTE: Do not confuse this procedure with
"checking the C.G." or "balancing the airplane fore and
aft''. That very important step will be covered later in the
manual.
Now that you have the basic airframe nearly completed,
this is a good time to balance the airplane laterally (side-to-
side). Since the wing is the major factor on a sailplane, we
will only be concerned with it. Here is how to do it:
D 1. Set the wing on a flat surface and hold it so that both
wing tips are level. Let go of the wing and notice which wing
tip drops. Do this several times and if the same wing tip keeps
dropping push a thumb tack or small nail through rib W10 into
the wing tip that keeps rising.
D 2. Perform this test several times until the wing bal-
ances or the same wing tip does not drop every time and then
glue the tacks or nails in place with a drop of thin CA.
FINAL SANDING
D 1. Harden the balsa in the area of the control horns (on
both control surfaces) by poking several holes with a pin, then
applying thin CA glue.
D 2. Check over the entire structure carefully, inspecting
for any poorly glued joints, gaps and "dings". Apply addi-
tional glue and/or balsa filler as necessary, then sand the
entire structure smooth using progressively finer grades of
sandpaper.
COVERING
There are many different types of covering materials
available these days but the iron-on type coverings are by far
the easiest to use and in most cases the best suited for the job.
There are also several different brands of iron-on coverings
available. We recommend you use Top Flite S uper Monokote
for covering your SPECTRA due to this covering's higher
strength. Sailplanes, which usually have higher "aspect
ratio'' wings (long and thin), gain a great deal of strength from
the covering. This is evident by gently twisting the wing
before and after it is covered, it is hard to believe the
difference. Because of this, the higher strength coverings are
best suited for sailplanes.
The following are some covering tips we have learned
over the years but you should follow the instructions in-
cluded with your covering material.
• Sand the surfaces as smooth as possible before starting to
cover the plane. The finished covering job will only be as
smooth as the surface you started with.
• Use a fresh single-edge razor blade or hobby knife blade
and replace the blade as soon as it starts showing signs of
dulling.
• Set the iron to the proper temperature by first applying a
"test strip" on a scrap of balsa.
• Work outward on sheeted surfaces, start by tacking the
covering in place at the comers and then start in the middle
and work your way out to the comers, gently pulling any
wrinkles out as you go.
• Securely seal all edges! Make sure the edges are firmly
sealed down to prevent the covering from pulling away at the
seams when shrinking the covering over open structures.
NOTE: When covering the fin, begin by applying a 1/2"
wide strip of covering on each triangle. Next, cover the rest
of the fin with pre-cut pieces that have a straight edge to
overlap (1/8"+ overlap) the strips you previously applied.
This is a tip you should remember as it makes it a lot easier to
cover "compound" curves.
Because the fin has to glue on top of the stab and the stab
must later be glued to the fuse, you do not want to cover where
these surfaces will glue to each other. The following instruc-
tions will explain how to do this.
D 1. Position the stabilizer on the fuselage and measure
to get it centered. Hold it in place and mark along the
fuselage/stabilizer joint with a felt pen to show where not to
cover.
D 2. Position the fin in place on top of the stab. Make sure
it is centered and pointing straight ahead, and mark around the
base with a felt tip pen.
0 3. When applying the covering to the top and bottom
surfaces of the stab, do each side with two pieces of covering.
Do not cover between the lines. Cut the covering to fit around
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