Tail assembly. A steel pin through a G10/FR4 fitting. Templates are on the plan for the fittings and control horns.
The elevator is covered and the pin is inserted from the end and a bit of covering or white glue secures the pin.
Servo
installation. The servo arm is outside the fuselage on the elevator
servo, like a Ford Trimotor. Drag from the Kevlar control runs is
minimal. Rudder
servo is right on the
back of the firewall. You can see one of the corner gussets at the
top of the fuselage. Make sure you angle them down to clear the
center of the wing as
shown on the plan. I make the loops in the Kevlar with 4 or 5
square knots and then drop some thin CA on the knot, wicking
the excess CA
off with a paper towel so it doesn't run down the line. Perhaps it
would be better to use a wire loop to attach the Kevlar to the servo
arm so there is no
relative movement on the Kevlar when the arm rotates. I haven't
seen any fraying yet.
Tail assembly.
A steel pin through a G10/FR4 fitting. Templates are on the
plan for the fittings and control horns.
The elevator is
covered and the pin is inserted from the end and a bit of covering or
white glue secures the pin.
This is the center
elevator pivot. Another G10/FR4 fitting that sides into grooves on
the stabilizer spar and glued with CA.
The little ply block in front holds the
carbon fiber carrythough in position
against the fitting.
Note the other little blocks about the centerline on the back of the
stabilizer spar. The
fin rear spar
fits between them. The notch
toward the front of the stabilizer in the center is
for the front fin spar. The photo shows the slot for
the elevator control horn on
the right side but that is because in this photo the elevator is upside down. In final assembly the
control horn is on the same side as the pivot fitting.
The tail assembly is removable on the
prototype. The aft fin spar continues to the bottom of the
fuselage and is trapped between the sideframes. The forward fin
spar goes through the notch in the stabilizer and also continues through
to the bottom of the fuselage. Balsa shims are installed inside
the longerons to maintain
a center position. A 2-56
rod goes through the fin lower
rib and the stabilizer, and then through a 1/32 ply plate on the bottom
of the fuselage. In
final assembly
a self locking nut is used, not
the plain nut shown. Note the ply doubler
under the bent portion of the rod on top. Thick CA glue holds the
rod to the ply and the
end of the rod is also bent down
and is stuck into the balsa. The
screw retains both the fin and stabilizer. On
the rudder a slot has been cut to receive
the control horn. The top rudder
pivot is steel pin with a companion hole
in the rudder. The
ply plate on the bottom of the fuselage is
the
lower rudder
pivot, a screw is used there. The
bottom of the rudder has balsa fairings to match the fuselage contour.
