18.104.22.168 Cuff heating area. The heating ele-
22.214.171.124 Fittings. Straight thread fittings
ments shall heat the leading edge of the cuff for
shall be in accordance with Specification MIL-
its entire length and at least 20 percent of both
cuff face areas emanating from the leading
3.20.4 Compound ice control system.
126.96.36.199 Compounds. The compound used
shall produce a surface which will prevent ice
188.8.131.52 Blade heating elements. Heating
adhesion when applied to the spinner, cuff, or
elements for propeller blades not equipped with
blade surface as applicable. No damage to the
cuffs shall be continuous throughout their
protected surface shall occur from the solution
length. The heated area shall approach as near
resulting when the compound comes into con-
as practicable the juncture between the blade
tact with water. The kind of compound used
and spinner or hub. Heating elements for pro-
shall be specified in the model specification.
peller blades equipped with cuffs may. be of
184.108.40.206 Protected blade area. The blade
two pieces with the cuff element and blade ele-
area to be protected by the compound shall not
ment separate, but compatible and designed for
be less than 75 percent of the blade length on
a single electrical supply circuit. The non-
inboard section and transversely from the lead-
heated length between cuff and blade elements
ing edge to include approximately 25 percent of
shall not exceed 2 inches. The external heating
element installation shall result. in no distor-
320.4.3 Protected cuff area. The cuff area
tion of the propeller airfoil contour.
to be protected by the compound shall be at least
220.127.116.11 Spinner heating area. The heating
20 percent of the cuff area on both cuff faces
elements shall heat the entire area of the rotat-
along the entire leading edge.
ing spinner surface.
18.104.22.168 Protected spinner area. The entire
3.20.23 Power requirements. The power re-
spinner surface shall be protected by the
quirements of the ice control system depend
on the mission, performance and design of the
3.20.5 Gas ice control system. Gas ice con-
specific aircraft application and shall be spec-
trol system shall produce sufficient heat to melt
ified in the model specification. Heating ele-
the layer of ice adhering to the surface of the
ment wattage shall be calculated after reducing
blade, cuff, and spinner, as applicable, which
will permit ice removal by action of centrifugal
drop in the complete circuit to each heating ele-
force or produce sufficient heat to prevent ice
ment. The type of phase loading, overload and
formation on the blade, cuff, and spinner, as ap-
open circuit sensing devices shall be described
plicable, and shall not affect the functional
in the model specification.
operation of the propeller or produce any un-
22.214.171.124 Cyclic heating controls. A cyclic
desirable structural or aerodynamic effects.
126.96.36.199 Ice control pattern. The system
control unit shall be provided as a component
shall accomplish a pattern of heat on the pro-
part of the system. The schedule of the cyclic
peller blades, cuffs, and spinners as necessary
c o n t r o l shall be specified in the model
to provide satisfactory ice control under the
conditions of table I.
3.20.3 Fluid ice control system.
188.8.131.52 Heat requirements. A complete def-
184.108.40.206 Fluid flow pattern. The system
inition of the heat source and heat requirements
shall accomplish a flow pattern of the fluid on
of the system shall be specified in the model
the propeller blades, cuffs, and spinner, as neces-
sary, to provide satisfactory ice control under
220.127.116.11 Controls. Protective devices sup-
the conditions of table I.
plied as part of the propeller system shall be
18.104.22.168 Fluid. The fluid, flow rate, and
specified in the model specification.
pressure shall be specified in the model specifica-
3.21 Connection identification. The pro-
peller shall be permanently marked for instru-
22.214.171.124 Connecting lines and fittings.
mentation and electrical and hydraulic connec-