The invention concerns an aircraft propulsion control system in which a gas turbine engine has an actuable flow opening for control of flow to or from a portion of the engine. One or more sensor is arranged to sense a condition indicative of vapor trail formation by the exhaust flow from the engine. A controller is arranged to control actuation of the flow opening so as to reduce the efficiency of the engine upon sensing of said condition by the one or more sensor. In one example, the flow opening is a variable area fan nozzle.

A system includes an engine configured to generate power to drive a load. The system also includes a power augmentation system configured to augment a power output of the engine when the power augmentation system is activated. Additionally, the system includes a controller operatively coupled to the power augmentation system. The controller is configured to estimate a potential change in the power output of the engine caused by activation of the power augmentation system using a power augmentation model and an engine performance model.

A bleed valve for an air plenum includes a valve body having a poppet seat, a poppet supported by the valve body and movable relative to the poppet seat, and piston slideable relative to the poppet and movable relative to the poppet between an extended position and a retracted position. Gas turbine engines and methods of bleeding fluid from gas turbine engines are also described.

A system for adjusting a variable position vane in an aircraft engine is disclosed. The system comprises a servo valve operatively connected to the variable position vane and configured to cause adjustment of the variable position vane based on a pressure of air pressurized by a compressor of the aircraft engine.

A system includes a blower, a blower sensor, and at least one processor. The blower sensor is operably coupled to the blower and configured to obtain blower operational information. The at least one processor is operably coupled to the blower and the blower sensor, and is configured to determine an operational-based power using the blower operational information; determine an operational-based density using the operational-based power; and control the blower using the operational-based density.

A method is provided during which an aircraft powerplant is provided. The aircraft powerplant includes a combustor and a water recovery system. The water recovery system includes a condenser and a reservoir. Fuel is combusted within the combustor to provide combustion products. Water is extracted from the combustion products using the condenser. The water recovery system is operated in one of a plurality of modes based on likelihood of contrail formation. The modes include a first mode and a second mode, where the water is collected within the reservoir during the first mode, and where the water passes through the water recovery system during the second mode.

There is provided a system and a method for controlling a tip clearance between a turbine casing and turbine blade tips of an aircraft engine. At least one operational parameter of the aircraft engine is obtained. Based on the at least one operational parameter, a current value of the tip clearance and a target value of the tip clearance are determined. A limiting factor to be applied to the target value of the tip clearance is computed. The limiting factor is applied to the target value of the tip clearance to obtain a tip clearance demand for the aircraft engine. A tip clearance control apparatus of the aircraft engine is controlled based on a difference between the current value of the tip clearance and the tip clearance demand.

A propulsion assembly for aircraft includes a single-shaft engine turbomachine including a combustion chamber and a rotatably mounted shaft that turns at a turbomachine rating; an electrical generator coupled to the shaft; and a control system. The control system includes a fuel pump that brings fuel into the combustion chamber at a fuel flow rate which is a direct function of an ambient pressure and of the turbomachine rating, and power electronics that are coupled to the electrical generator and that control an electrical power drawn off the electrical generator so as to attain a target turbomachine rating.

A bleed valve for an air plenum includes a valve body having a poppet seat, a poppet supported by the valve body and movable relative to the poppet seat, and piston slideable relative to the poppet and movable relative to the poppet between an extended position and a retracted position. Gas turbine engines and methods of bleeding fluid from gas turbine engines are also described.

A fuel cell system includes a control unit that is configured to perform highland control for increasing an amount of electric power generated per unit time by a fuel cell and increasing a rotational speed of a compressor such that an operating point of the compressor falls outside a surging region, in comparison with a case where a highland condition that an outside air pressure determined from an outside air pressure-associated information is lower than an outside air pressure threshold determined in advance is not fulfilled, when the highland condition is fulfilled in starting electric power generation by the fuel cell.