MIL-DTL-8777F
exceed 50° per minute. After maintaining this temperature for 4 hours, and while still at this low
temperature, the cable shall be wrapped around the mandrel for 180° without opening the cold chamber.
A revolving mandrel inside the cold chamber and operated by a control external to the chamber shall be
used. The time required for bending the sample around 180° of the mandrel shall be 30 seconds and the
bending shall be performed at a uniform rate of speed. The specimen shall then be examined for cracks
(see 3.4.4.4). The insulation shall be removed for a distance of 1 inch (25.40 mm) from each end of the
specimen and the specimen subjected to the test specified in 4.6.4.3.3 with the bent portion submerged.
4.6.4.5 Oil absorption. A specimen of untested wire not less than 24 inches (609.60 mm) long shall be
immersed to within 1.5 inches (38.10 mm) from each end in a liquid containing equal parts of kerosene
and aircraft-engine lubricating oil, and a temperature of 50° ±5°C for 20 hours. The specimen shall then
be examined for increase in diameter, after which it shall be successively subjected to the tests specified
4.6.4.6 Immersion. Separate specimens of wire, not less than 24 inches (609.60 mm) long, shall be
immersed to within 6 inches (152.40 mm) of each end, for a period of 20 hours at normal room
temperature, in each of the following fluids (using a separate specimen for each fluid):
a. Lubricating oil conforming to MIL-PRF-7808.
b. Hydraulic fluid conforming to MIL-PRF-5606.
c. Hydraulic fluid conforming to SAE AS1241.
d. Jet fuel (grade JP-4) conforming to MIL-DTL-5624.
e. Isopropyl alcohol conforming to TT-I-735.
Upon removal from the fluid, the specimen shall remain for 1 hour in free air at normal room
temperature. The insulation shall be removed for a distance of 1 inch (25.40 mm) from each end of the
specimen and the specimen subjected to the test specified in 4.6.4.3.3. During immersion tests, the
bend of the wire shall be not less than 14 times the maximum specified diameter of that particular size
wire.
4.6.4.7 High temperature endurance. The wire shall be subjected to the current loading specified for
single cables in free air as specified in the table titled "Current-carrying capacity of wires and cables" as
specified in MIL-W-5088, except that the ambient temperature shall be 150° ±5°C for 200 hours.
Separate samples of the wire shall then be tested as specified in and shall meet the requirements of the
4.6.4.8 Flammability.
4.6.4.8.1 Apparatus. A Bunsen burner having a 0.25 inch (6.35mm) inlet, a nominal bore of .0.375 inch
(9.53 mm), and a stem or burner length of approximately 4 inches (101.60 mm) above the air inlets shall
be used for the tests. The Bunsen burner shall be of the type having a needle valve for gas adjustment
built into the bottom of the burner. A wing-top flame spreader having a 0.0625 inch (1.59 mm) by 2 inch
(50.80 mm) opening shall be fitted on the tip of the burner. The air inlet valve and the gas needle valve
shall be adjusted so that a 2 inch (50.80 mm) high all blue flame is obtained having a temperature of 870°
±30°C at the top. It is optional to use a 2 inch (50.80 mm) high flame having an inner cone 0.33 inch
(8.38mm) its height, provided the tip of the inner cone shall have the specified temperature. The shape of
the 2 inch (50.80 mm) flame spreader and the flame shall be as illustrated on figure 1.
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