THRUSH AIRCRAFT, INC – MODEL S2R-R1340
AIRCRAFT MAINTENANCE MANUAL
Effective: 01/01/08
7-25
B. Install
the
spar
web splice plate and
the upper and lower main spar cap
splice fittings in accordance with the
normal installation procedure
described previously. Torque all
nuts to specification per Table 7-3.
C. Install the wing attach bolts at the left
and right rear spars and torque to
specification.
D. On the 20243-3 wing attach angles
(outboard only), draw a heavy black
line from top to bottom so as to
bisect the forward face of the flange
when it is positioned on the aircraft.
E. Position these outboard angles so
that they mate flush with the
bushings through the vertical
fuselage tube, flush with the spar
web and contact the top of the lower
spar cap. Now raise the angle so
that there is approximately a 3/16
inch clearance between the angle
and the spar cap. Clamp the angle
to the vertical fuselage member.
F. Sight through the outboard vertical
row of ¼” bolt holes in the main spar
web and position the wings so that
black lines drawn in step “D” are
visible and that they appear
symmetrical between left and right
wings. This centers the wings with
respect to the fuselage. Repeat step
“E” if the 3/16 inch clearance has
changed.
G. Transfer the location of each of the
holes through the bushings in the
vertical fuselage member to the
attach angle by sliding a 5/16 inch
drill bit (preferably one that has a
pilot tip), through each of the four
holes in succession. Twist the drill
just enough to make a mark on the
angle. Do not drill these holes yet
because edge distance must be
checked.
H. Remove the angle and check to
confirm that the mark for the bottom
hole is at least 5/8 (2X hole
diameter) inch away from the lower
edge of the angle. If it is not, file the
bottom edge of the other leg of the
angle (which comes into contact with
the lower spar cap) in such a manner
as to allow the angle to be lowered
and yet provide clearance from the
lower spar cap. Repeat the hole
transfer procedure and recheck for
edge distance if adjustments had to
be made..
I.
When the wings are properly located
and edge distance is adequate, mark
the four fuselage bushing locations
on the outboard angles by using a
transfer punch through the bushings.
J. Remove the outboard attach angles
and drill the 5/16” holes in the
punched locations.
K. Place the inboard attach angles back
to back against the outboard angles.
Align and clamp the two angles and
transfer drill the 5/16 inch holes
through the inboard angles using the
holes in the outboard attach angles
as a drill guide..
L. Temporarily install the four wing
attach angles to the fuselage down
tubes and torque the 5/16 inch nuts
and bolts to specification.
M. Again sight through the ¼ inch bolt
holes through the main spar web and
confirm that the black lines appear
symmetrical between the left and
right wings.
N. Transfer the location of the ¼ inch
holes to the four wing attach angles,
using the main spar web as an
index. A few holes may be drilled
and bolts installed to keep the spar
web flush with the forward face of the
angles for transfer accuracy. Use
caution not to enlarge the holes
through the spar web.
O. Mark and remove the four attach
angles and drill and ream the ¼ inch
holes at the marked locations with a
drill press or milling machine
(.250”/.254”). Deburr all holes.
