MIL-DTL-87255 Valves, Pressure, Anti-G Suit, High FlowThis specification covers a high-flow, pressure regulating valve for inflating anti-G suits and providing a sense line signal for a g-compensated oxygen regulator \(if applicable\). It also includes details of inlet and outlet fittings required to interface the valve to specific aircraft.

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MIL-DTL-87255A(USAF)

4.5.12.2.4

Repeat test.

Repeat the tests of 4.5.12.2.3 using an onset and offset rate of 4 Gz per sec and ensuring that

the valve's performance meets the requirements of 3.5.2

4.5.12.2.5

Test for anti-chatter.

The valve shall be checked for anti-chatter by mounting an MXU-804/A or an MXU-805/A in the

centrifuge and connecting it to a standard anti-g suit. A profile that shall cause this valve to

chatter shall be run (approximately 3-5 Gz with an onset rate of 3 Gz per sec; the inlet to the anti-

g suit may need to be restricted to induce the chatter). After chatter has been induced in this

valve, replace the valve with the valve under test without disturbing the rest of the set-up. Run

the same profile that caused the chatter and insure no chatter shall be present in the valve

under test.

4.5.13 Endurance.

A tank shall be connected as specified in 4.4.4 during this test. A source of pressurized gas

shall be connected to the inlet and the valve shall be subjected to cyclic operations for the

number of cycles (see 6.4.3), under the conditions, and in the order specified in table VII. The

rate of cycling shall be approximately 6 cycles per minute. The outlet pressure at the maximum

force of each cycle shall be in accordance with 3.5.2 for the applied force. After completing all

phases of the cyclic operation, the valve shall be subjected to and pass the inspections

specified in 4.5.2 through 4.5.6; except that the minimum operating force can be between 1.25

and 2.0 Gz.

TABLE VII. Conditions of cyclic operation.

Inlet Pressure

Inlet Air Temperature

Applied Force

Number of Cycles

(psig)

(�F)

(Gz)

150

1 to 6 to 1

5,000

150

1 to 9 to 1

300

400

1 to 6 to 1

1,000

300

400

1 to 9 to 1

150

400

1 to 6 to 1

4,000

150

1 to 6 to 1

5,000

4.5.14 Disassembly and examination.

At the conclusion of all inspections specified herein, the valve shall be disassembled and

examined. The valve shall not show evidence of excessive deterioration or wear due to testing

which might affect the valve performance. The valve shall be disassembled and examined after

any test in which valve failure indicates faulty construction.