14
❑
5) There’s one more thing to do before gluing the stabilizer
onto the fuselage! That is preparing the stab and elevators for
hinging. It’s a lot easier to do it now while you can still hold the
individual parts in your hands. Refer back to step 7 of the WING
ASSEMBLY (on page 5) for step-by-step guidance on installing
hinges. Note that there are 3 hinges per elevator. Go ahead and
permanently glue the hinges into the elevators at this point, but not
into the stabilizer. Let dry.
❑
6) The stabilizer can now be glued permanently in place on the
fuselage. Use slow-drying epoxy glue for this step. First apply glue
to the stab saddle area of the fuselage and then place the stab
squarely in position - use a weight to hold it in position. View the
airplane from the top, front and rear, making sure the stab is square,
without leaning one way or the other. Use a ruler to measure from
the outer trailing edge wingtip back to the stab's leading edge tip
and note the measurement and repeat this process on the opposite
side.
The two measurements should be the same.
Make
adjustments as needed. Tape and/or weight the stab firmly in place
to the fuselage, wipe off any excess glue with alcohol and allow the
glue to set. Remove the wing from the fuselage.
❑
7) Prepare the fin and rudder for hinging. Note that there are
3 hinges in the fin/rudder. Go ahead and glue the hinges in the
rudder at this point, but not into the fin. Let dry.
❑
8) Trial fit the fin in place on the fuse. The bottom of the fin
should sit on top of the stabilizer without any big gaps.
a. View and measure the alignment of the stabilizer to the entire
airplane from several different angles. Make sure that the fin is
absolutely 90
O
upright on the fuselage, and that it is aligned
straight with the centerline of the fuselage, not turned left or right.
b. When satisfied with the alignment, use a felt-tip pen to mark
the fin location on top of the stab. Take the fin off and carefully
remove the covering material from the stab just inside of the lines.
NOTE: Accurate alignment is ultra critical to the performance of
an aerobatic airplane like the EXTRA.
For that reason, we
recommend that you buy or borrow an accurate "incidence meter"
(like a Robart
®
Incidence Meter) to help with the final alignment of
the tail surfaces during the next steps.
❑
2) Use a ruler to find the exact center of the stabilizer at the
trailing edge, marking the location with a felt-tip pen. Use a 90
O
triangle to draw a centerline on the stab at this location.
❑
3) Bolt the wing in place on the fuselage. Attach an incidence
meter to the leading and trailing edges of the wing, near the
fuselage. Then prop up the rear of the fuselage until it is level
according to the meter, reading 0
O
. Place the stabilizer in its saddle
in the fuselage and use pins to hold it in place. With the stab in this
position, carefully remove the incidence meter from the wing and
attach it to the stabilizer, without jarring the position of the airplane.
Ideally the meter will again read 0
O
. If it does not, then the stab
saddle in the fuselage must be adjusted to seat the stab at 0
O
. Use
a sanding block to adjust the stab saddle as needed.
❑
4) With the stabilizer in correct alignment on the fuselage, use
a felt-tip pen to mark the location of the fuselage sides on the
bottom of the stab. Then remove the stabilizer and use a sharp
blade to carefully remove the covering material just inside of these
two lines, including where it contacts the fuselage at its leading and
trailing edges.
BE VERY CAREFUL NOT TO CUT INTO THE
BALSA WOOD!