Figure 4.25. Variable Inlet Guide Vane Angle of Attack.
The air bleed actuator, shown in figure 4.28, operates by
compressor discharge air (P3)which is extracted from a port on the
right side of the air diffuser housing.
The air entering the actuator assembly passes through a filter
to the underside of the relay valve diaphragm. A small portion of
this air, which is under the diaphragm, is bled through an orifice in
the base of the relay valve assembly to an external line which
directs it to a slide valve located on the fuel regulator housing.