The Model 34E56 engine-driven variable delivery hydraulic Nozzle Control Pump is used on GE J79 augmented engines to provide a high pressure, fully flow reversible hydraulic power source for exhaust nozzle actuation. The pump delivers fluid at a rate proportional to a mechanical input signal. The unit includes a built-in boost element for servo and makeup flow.

• Replenishing shuttle valve system to make up fluid required by differential actuator volume
• Combination bleed and shuttle valve to return oil from the low pressure side of the system to the reservoir for system cooling
• Face-type carbon seal to prevent leakage from pump case to drive cavity
• Integral high-pressure relief valves adjustable to 4750 psi at each of the two discharge ports