Cessna T188C - Page 405

MODEL 188 & T188 SERIES SERVICE MANUAL
adhesive to provide generous fillets at the core-to- give better adhesion.
skin junction, to repair the delamination.
d. Mix the filler material according
to directions
17-82. SUBSTITUTING BLIND
RIVETS FOR SOLID
furnished,
fill the
exposed
honeycomb
core and
RIVETS.
cavity, and complete the repair per Class II, steps
"d"
thru "1."
17-83.
GENERAL CONSIDERATIONS.
Where re-
placement of solid rivets is difficult due to limited
REPAIR
OF CLASS IV DAMAGE,
access
for proper driving and bucking,
blind rivets
a. Thoroughly clean the area
with acetone, ketone,
may be used within the guidelines
of these pro-
or
other similar solvent that leaves
no residue. cedures.
Blind rivets should not be
used in main
b. Carefully remove
outer skin, honeycomb core,
wing spars unless
specified in a Cessna Service Kit,
and inner skin to remove all damage and delamination. or when approved by the Cessna Service Department.
Remove additional
outer skin and honeycomb core
CR162, CR163, CR762
and CR763 rivets should
not
as necessary
to provide a two-inch bearing
area be used in structural
load carrying members
such as
around
periphery of opening in inner
skin. wing spars,
ribs, stringers and doublers
or fuselage
c. Cut out an aluminum patch
(. 025" minimum thick-
bulkheads, longerons and fitting
attachments. If
ness) to overlap the inner
skin opening one inch.
there is any question
concerning the use of these
Trim a piece of glass-fiber
cloth to overlap the inner
rivets contact the Cessna
Service Department.
skin opening two inches. Cut a hole in the cloth to
match
the opening
in the inner
skin.
17-84.
BLIND RIVET
SUBSTITUTION.
Blind rivets
d. Mix
the
adhesive
according
to directions
fur-
may
be
substituted
for
solid
rivets
on
a one-for-one
nished.
basis,
either
the same
size or larger,
provided
that
e.
Brush
the adhesive
around
opening
in
inner
skin.
restrictions
outlined
in paragraph
17-83 are
met,
Place
the ring
of cloth in
position and
thoroughly
wet
shear
strength of
the blind
rivet is
equivalent
or
with
the
adhesive
to
provide
a "bed"
for
the alumi-
greater
than
the
solid
rivet (see
figure
17-17),
and
num patch.
the rivet
edge margin,
spacing
and grip
length is
in
f. Clean
the aluminum
patch
with acetone,
ketone,
accordance
with figure
17-18.
When
substitution
on
or
other similar solvent that leaves
no residue, and a one-for-one
basis s not possible,
refer to para-
brush the contacting
area of the patch
with the adhe-
graph 17-85.
sive. Place
the patch
in position.
g. Mix the filler
material according to directions
17-85. DETERMINING
QUANTITY OF SUBSTITUTE
furnished.
BLIND
RIVETS.
When
shear
strength
cannot
be
h.
Fill the cavity,
flush
with the top
of the honey-
maintained
with a
one-for-one
substitution,
additional
comb
core,
with this
putty-like
mixture.
If a large
blind
rivets will
be required.
Determine
the
total
area
is being
repaired,
be
sure to
restore
original
number
of blind
rivets
required
by using
figure
17-17
wing contour.
with the following calculation:
shear strength of the
i. Complete
the repair per
Class II, steps
"d"
solid rivet size
multiplied
by the number
of solid
thru "1."
rivets
in the row
being replaced.
Divide this
total
shear
strength by the
shear strength
of the substitute
17-81.
REPAIR
OF GLASS-FIBER
CONSTRUCTED
blind rivet
size.
Round off
the answer
to the next
COMPONENTS.
Glass-fiber
constructed
components
highest
whole number
of substitute
blind
rivets
re-
on
the aircraft
may be
repaired
as stipulated
in Ser-
quired
for that
row. Maintain
edge
margin, spacing
vice
Kit SK182-12.
Observe
the
resin manufacturer's
and grip
length specified
in
figure 17-18.
recommendations
concerning
mixing
and application
of the resin. Epoxy
resins are preferable for
making 17-86. FASTENER
SUBSTITUTION. For approved
repairs,
since epoxy
compounds
are
usually
more
fastener
substitutions,
See figure
17-19.
stable and predictablt than polyester and, in addition,
SHOP NOTES:
Revision
1
17-43