S e c t ion VI.
a dual purpose coating to be used as a thermally
reflective coating on exterior laminated plastic
N A T E MATERIALS.
parts where protection from rain erosion is
required. For economic reasons, the thermally
a. Sandwich-type laminate parts in aircraft
reflective coating will be used only where both
are coated for several reasons with the type of
thermal and erosion protection is an established
coating being chosen for the specific application
of the part. Plastic parts such as radomes are
normally coated primarily for rain erosion resis-
a. Rain erosion resistant coating systems,
tance. Paints shall not be applied to radomes or
Military Specification MIL-C-83231.
antennas unless specifically directed in 6-17.
b. In repairing sandwich-type laminate parts,
(1) Class A, Type I, is a rain erosion
the final step is to refinish the part with a finish
resistant coating furnished in complete kit form.
identical to the original finish. (Refer to drawings
(2) Class A, Type II, is a rain erosion
and applicable specifications of the parts).
resistant coating with antistatic surface treat-
charging of the coated surface furnished in com-
plete kit form.
There will be no protective coating
sprayed upon radomes for prevention of
b. Thermally reflective coating system, Mili-
scratching or marring during transport"
tary Specification MIL-C-83445, are classified as
tion. As previously emphasized, items
require special handling at all times to
(1) Class I rain erosion resistant thermal
prevent damage. Addition of protective
coating furnished in kit form complete with pri-
coatings for prevention of such damage
mer, erosion resistant (electrically nonconductive)
would not prevent major damage and
component, and diluting solvent.
would tend to reemphasize special
handling precautions. Surface will be
(2) The coatings are intended for exterior
protected by covering with paper or sim-
laminated plastic parts of aircraft for protection
from rain erosion and thermal energy while the
aircraft is in flight. These coatings cannot be used
PROTECTIVE COATINGS FOR
on radomes and other plastic parts that have a
R A I N EROSION. F i b e r g l a s s l a m i n a t e d s u r -
requirement for protection against static
face located on the frontal areas of aircraft are
electrical charges because they are not electri-
subjected to considerable erosive action when
flying through rain. These areas must be
protected to prevent severe damage to the fiber-
c. Provide rain erosion protection on wing
glass surface. Rain erosion coating systems con-
tip assemblies and other aircraft parts con-
forming to Military Specification MIL-C-83231 and
structed of fiber laminates which present an in-
MIL-C-83445 applied to affected surfaces will pro-
flight angle of impact of 15 degrees or more. Do
vide protection from the effects of rain erosion.
not provide rain erosion protection on Ieading
These materials will protect the fiberglass surface
edges and areas of radomes and antenna hous-
indefinitely, providing the coating is replaced or
ings unless specifically directed in 6-17. Head-on
repaired when inspection indicates such work is
impact of a flat surface is defined as a 90-degree
necessary. Thermally reflective elastomeric coat-
ing system, Military Specification MIL-C-83445 is