Great Planes Extra 300S 40 Kit - GPMA0235 - Manual (Page 38)

This step is optional but will enhance the scale
appearance of your Extra 300.
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3. Test fit the die-cut 1/8" plywood fuselage side
stringers in the fuselage sides as shown on the plans, then
use medium CA to glue them into position.
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4. Most of the model should be rough-sanded by now
with all the tabs and rough edges sanded even. Fill all
dents, seams, low spots and notches with HobbyLite balsa
colored filler.
❏
5. After the filler has dried use progressively finer grades
of sandpaper to even and smooth all the edges, seams and
surfaces. Remove all balsa dust from the model with
compressed air or a vacuum with a brush and a tack cloth.
Cover the model with Top Flite MonoKote Film using the
recommended covering sequence that follows. Before you
cover the fuselage, first apply 1/4" wide strips of MonoKote film
in the corners of the stab and fuse and the fin and the fuse,
then proceed to cover the fin and stab with pre-cut pieces that
meet in the corners and overlap the 1/4" strips. Never cut the
covering on the stab and fin after it has been applied
except around the leading and trailing edges at the tips.
Modelers who do this may cut through the covering and into
the stab or fin. This will weaken the structure to a point where it
may fail during flight. Since the tips of the elevators and stab
are squared off it is easiest to cover the tips before you cover
the tops and bottoms. Do the same for the fin, rudder and the
wing. Some modelers drill a small hole in each stab rib and the
trailing edge of the stab to allow expanded gas to exit while
heating the MonoKote film. This procedure keeps the covering
from “ballooning” and allows you to securely bond it to the
entire stab. The same thing can be done with the elevators, fin
and rudder.
When you cover the fuselage, use your covering iron to seal
only the top of the turtle deck in the center and the bottom
of the fuse. Use your heat gun to shrink the rest of the
covering on the fuselage, especially near the side stringers.
This will provide a realistic, smooth transition from the turtle
deck, over the side stringers, down to the fuse bottom.
Since the ailerons are long “strip” ailerons some modelers
prefer to cover the top and bottom with one strip of
MonoKote film by covering the bottom first, then wrapping it
around the leading edge over the top.
Fuselage
1. 1/4" strips at fin and stab as described
2. Aft fuse bottom
3. Forward fuse bottom
4. Fuse right side up to the top center of the turtle deck
5. Fuse left side up to the top center of the turtle deck,
overlapping by 1/8"
6. Forward fuse deck top
7. Fin tip, then stab tips
8. Stab bottom, then top
9. Fin right side, then left side
10. Elevator tips and root ends
11. Elevator bottoms, then tops
12. Rudder tip, then right side, then left side
Wing
1. Wing root spacers
2. Wing tips
3. Trailing edges of wing and inboard portion of tips and
center leading edges
4. Belly pan bottom, then sides
5. Bottom of right, then left panel
6. Top of right, then left panel
7. Aileron tips, then bottom, then top of aileron
Suggested Covering Sequence
Covering Technique
COVERING
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