TEST CHAMBER ASSEMBLY
THEORY OF OPERATION
THEORY OF OPERATION (MODEL 452)
The test chamber components are arranged according to the schematic diagram. The air
compressor supplies compressed air at 40 PSI. It is used to cock the AR2 being tested and
provides controlled air pressure to the altitude chamber. The rate at which air is introduced into
the altitude chamber controls the simulated rate-of-fall of the AR2.
When in operation, if the air solenoid valve is opened by positioning the CLIMB/FALL/COCK
switch to COCK, compressed air flows into the air cylinder and forces the piston to the right. This
will cock the AR2. When the CLIMB/FALL/COCK switch is moved from the COCK position a vent
in the solenoid valve allows the compressed air behind the piston to bleed off, thus enabling the
AR2 to actuate under the appropriate conditions.
Compressed air is also available to the PRESSURE CONTROL regulator, which controls the rate
at which air is introduced into the altitude chamber. Outlet pressure from the PRESSURE
CONTROL regulator is registered on the pressure (PSI) gauge. Air thus regulated passes
through a restrictor and on into the altitude chamber. By controlling the pressure, the simulated
rate of fall of the AR2 may be varied.
The vacuum pump is connected to the altitude chamber through the ALTITUDE CONTROL
regulator, which allows selection of any desired altitude up to 35,000 feet. When the
CLIMB/FALL/COCK switch is moved to the CLIMB position, the climb solenoid valve opens.
Turning the ALTITUDE CONTROL regulator knob allows selection of the desired altitude.
Turning the knob counterclockwise will increase altitude. When the CLIMB/FALL/COCK switch is
moved to the FALL position, the climb solenoid valve closes and the restrictor in the line from the
PRESSURE CONTROL regulator allows controlled air pressure to enter the altitude chamber,
causing the altitude to gradually decrease.
The RAPID FALL dump switch (push button) controls the dump solenoid valve. When the RAPID
FALL dump switch is pressed the dump solenoid valve opens, and air from the compressor is
introduced directly into the altitude chamber for rapid descent.
The ON/OFF switch controls power to both the air compressor and vacuum pump. When the air
compressor and vacuum pump are running, the indicator light will illuminate. It will extinguish
when the ON/OFF switch is positioned to OFF.