.
Covering The Fuselage
The fuselage should be covered with six pieces in the order described here:
Fuselage Bottom - 2 pieces, front and rear
Fuselage Sides - 2 pieces, left and right
Fuselage Top - 2 pieces, top deck and stringers
All seams should overlap about 3/16". When covering solid wood surfaces like the front of the fuselage sides, better
results can be obtained by starting at the center and working toward the outer edges, allowing air to escape as you iron.
The trickiest part of covering the fuselage is the stringer area. Start by applying one edge of the covering to one of the
fuselage sides, overlapping 3/16" onto the side covering. Drape the material over the stringers, pulling out any major
wrinkles. Carefully tack the material to the other fuselage side,then trim off the excess, again leaving a 3/16" overlap. To
avoid slicing into the material underneath, slide a piece of thin cardboard under the excess stringer covering before cutting
it with a knife. Use a straight edge to make a nice, straight cut.
Go back over the side seams with your iron, then seal the material to HR at the front as well as F-6 and the tail fairing
blocks at the rear. Trim away the excess covering at the rear flush with the edges of the fairing blocks and F-6. At the
front, leave a 1/8" overhang forward of the headrest (HR) to iron around the corner. Seal down the overhang to the front of
HR (you may find that slits in the overhang every 1/4" or so will help during this step). Now you can use a heat gun or iron
to shrink the rest of the material over the stringers.
Covering The Tail Sufaces And Ailerons
The stabilizer, elevators, fin, rudder, and ailerons should each be covered with two pieces of material - bottom first, then
the top. Iron the material from the center out to avoid trapping air bubbles. Be sure to cover the back edge of the fin trailing
edge all the way to the bottom.
Covering with Sig Koverall And Dope
Koverall is a polyester-base, heat-shrinkable, synthetic fabric much like the covering used on full-scale aircraft, only lighter.
Its toughness and relatively low cost make it ideally suited to giant scale and giant sport models. One large package of
Koverall (SIGKV003, 48" x 5 yds.) is plenty of material to cover the Four-Star 120. It can be applied to the structure using
dope or Sig Stix-It, and heat-activated adhesive.
Surface Preparation
Whichever application method is used, you should first brush two coats of clear dope onto the framework wherever the
covering material makes contact (even the edges of the wing ribs). If you plan to use dope for the entire finish, use Sig
Lite-Coat (low-shrink butyrate dope) for the first two coats. If you plan to use enamels or epoxy colors, use Sig Nitrate
dope. Lightly sand after each coat to remove any raised grain or fuzz.
Applying Koverall With Dope
The bottom of an outer wing panel is a good place to start covering. Cut a piece of material about an inch larger all around
the panel, with the grain running spanwise. (The grain of woven materials runs parallel to the finished bias edge.) Lay the
Koverall on the wing, pulling out any major wrinkles. Koverall shrinks up considerably under heat - there's no need to
worry about such things as packaging fold creases because they will come out easily with the iron. Brush clear dope
around all the edges. This will soak through the fabric and adhere it to the dope already dried into the framework. Allow the
dope to dry before trimming off the excess material with a sharp razor blade. Check for any rough edges or places that are
not stuck down properly and apply more dope. Let dry.
Applying Koverall With Stix-It
Directions for using Stix-It are on the can. The basic procedure is to apply Stix-It around the edges of the framework where
you want the covering to attach. When dry, the fabric can be ironed-on around the edges where the Stix-It was applied.
Summary of Contents for Four-Star 120
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