Skins And Core - Bell OH-58A Technical Manual

PERSONNEL/TIME REQUIRED:
1 Soldier
. 2 Hours
MATERIALS/TOOLS REQUIRED:
. Drill with No. 30 Bit
Router
Metal Set (item 2, Appx C) or
Equivalent Filler Compound
2 Patch Plates
. Cherry Rivets (item 38, Appx C)
Rivet Gun
Solvent (item 47, Appx C)
PROCEDURAL STEPS:
Remove damaged skin and core using a
1.
router to route all damage on outer and
inner skins. Enlarge the hole on the
outer skin and honeycomb so that a 1
Inch rim surface of the inner skin is
exposed, as shown in Figure 4-26.
Make two patch plates. One patch
2.
plate is for inner skin; the other for
the outer skin, Figure 4-27.
Apply sealant to exposed surface of
3.
inner skin. Assemble patch plate to the
inner skin with cherry rivets.
4. Completely fill void with metal set
fill compound. Add slight excess to
allow for shrinkage.
Let harden. Sand smooth.
5.
sealant to the area between the outer
Assemble patch to outer
patch and skin.
skin with 1/8 cherry rivets.
6. Record BDAR action taken. When
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.
Damage Over 8 Inches to Both
OPTION 4:

Skins and Core.

LIMITATIONS: None.
PERSONNEL/TIME REQUIRED:
1 Soldier
2 Hours
MATERIALS/TOOLS REQUIRED:
. 2 Patch Plates
Cherry Rivets
PROCEDURAL STEPS:
Remove damaged skin and core, Figure
1.
4-28. Clean top and bottom skins 6
inches around holes with cleaner. The
maximum damaged area that may be cut out
is 12 inches.
2. Make two patch plates, 0.04 inch or
thicker, as shown in Figure 4-28. (If
damage is in an area where installing an
interior patch is not possible or where
sharp edges from rivets on an interior
patch might cause damage, a single
exterior patch plate, 0.05 inch thick,
may be used.) Make plates 2 inches
larger than the cutout. Lay out and
drill a rivet pattern, two rows, as
shown.
Assemble with 2 rows of cherry rivets.
3.
4. Record BDAR action taken. When
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.
OPTION 5:
LIMITATIONS:
for secondary structural areas, which
Apply have a honeycomb core between the walls,
where repair is required for aerodynamic
reasons or to keep water out of aircraft.
PERSONNEL/TIME REQUIRED:
1 Soldier
. 1 Hour
MATERIAL/TOOLS REQUIRED:
Patch Plate, 0.020 Inch (Minimum)
Aluminum or Steel
Cherry Rivets (item 38, Appx C)
Sealant (item 5, Appx C)
. Rivet Gun
Solvent (item 7, Appx C)
. Drill and Bit
TM 55-1520-228-BD
Secondary Structure Repair.
This option is recommended
AIRFRAME
4-65