Fluid power in the hydraulic system of modern aircraft equipped with powered flying controls, is generated by a constant pressure/variable delivery pump. The control mechanism of the pump is arranged to maintain constant pressure at all flow rates up to the maximum flow rate, at which point pressure drops to zero. Practical considerations modify this ideal slightly, but pressure is kept as constant as possible, falling by perhaps 3,5 % between zero flow and 95 % full flow. Thus at all times in the flight envelope, the rated pressure will be supplied to the actuator package regardless of the load acting on the actuator. The actuator package consists of a hydraulic jack or motor plus a control valve which controls the rate and direction of motion. Regardless of the magnitude of the load to be moved, the control valve passes the demanded flow by adjusting its flow area appropriate to the difference in supply pressure (PS) and the pressure required to react the load (PL). The pressure drop PS - PL represents a wastage of power which converts into heat.
Development of variable pressure hydraulic systems for military aircraft utilising the 'smart hydraulic pump'
Entwicklung von Hydrauliksystemen mit variablem Druck für Militärflugzeuge unter Verwendung der 'intelligenten hydraulischen Pumpe'
1993
11 Seiten, 7 Bilder, 3 Quellen
Aufsatz (Konferenz)
Englisch
British Library Conference Proceedings | 1993
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