MIL-DTL-8790F
TABLE VI. Impulse cycles.
Maximum impulse cycles
Minimum impulse
Minimum average
Hose
that can be used to
impulse cycles 1/
cycles per hose
size no.
compute average 2/
4
100,000
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5
100,000
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6
100,000
---
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8
75,000
100,000
150,000
10
50,000
75,000
100,000
12
35,000
50,000
70,000
16
45,000
55,000
75,000
1/ The average of the test samples shall not be below the values listed in this column.
2/ When test samples impulse cycles are averaged, the maximum cycles that may be used to
compute the average shall not exceed the figures given in this column. This column is giving
a limit to the number of impulse cycles that are allowed to calculate the average. While testing
is in progress the test operator will take a reading of the impulse cycles completed. If it's
higher than the value in column 4 the test operator would use the value specified in the table
not the higher (true) value from the reading.
4.9.7 Low temperature flexibility test. Hose when subjected to low temperature flexibility testing shall
meet the requirements of 3.7.6. The following details shall apply:
a. Two samples of the lengths specified in table I.
b. One sample shall be unaged, while the other shall be oil aged prior to testing.
c. Samples shall be filled with fluid in accordance with MIL-PRF-5606, MIL-PRF-83282, or
MIL-PRF-87257 and then exposed for 24 hours in a chamber at a temperature of -65°F ±2°F
(-53.9°C +1.11°C).
d. After the 24 hour exposure and while still at the specified temperature, the samples shall be
flexed through 180° at each extreme travel (see figure 2), considered as one cycle, to the
applicable inside bend radius specified in table I.
e. Each sample shall be subjected to one cycle only, the duration of which shall be no greater
than four seconds.
f. After the flexing cycle (see figure 2), samples shall be removed from the cold chamber and
subjected to the proof pressure test (see 4.9.3).
FIGURE 2. Flexibility test set up.
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