Page 184 - The Jet Engine

Fig. 16-4 Typical afterburning jet pipe equipment.

17. When afterburning is selected, a signal is afterburning, the nozzle area is progressively
relayed to the afterburner fuel control unit. The unit increased to maintain a satisfactory P3/P6 ratio. Fig.
determines the total fuel delivery of the pump and 16-6 illustrates a typical afterburner fuel control
controls the distribution of fuel flow to the burner system.
assembly. Fuel from the burners is ignited, resulting
in an increase in jet pipe pressure (P6). This alters 18. To operate the propelling nozzle against the
the pressure ratio across the turbine (P3/P6), and the large 'drag' loads imposed by the gas stream, a
exit area of the jet pipe nozzle is automatically pump and either hydraulically or pneumatically
increased until the correct PS/PS ratio has been operated rams are incorporated in the control
restored. With a further increase in the degree of system. The system shown in fig. 16-7 uses oil as the

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