A propulsion system for an aircraft having an aft end is provided herein. The propulsion system can include an electric propulsion engine defining a central axis. The electric propulsion engine can include an electric motor, a fan rotatable about the central axis of the electric propulsion engine by the electric motor, a bearing supporting rotation of the fan, and a thermal management system. The thermal management system can include a lubrication oil circulation assembly for providing the bearing with lubrication oil. The lubrication oil circulation assembly can be driven independently of a shaft of the electric propulsion engine.

A fan module includes a first casing, a driving motor disposed in the first casing, a first rotor connected to the first driving motor, a second casing, a second rotor pivotally configured in the second casing, at least one guiding member and a shift apparatus connected to the first casing and the second casing, the first rotor includes a first rotating shaft and a plurality of first blades, the second rotor includes a second rotating shaft and a plurality of second blades, the guiding member is disposed on the first blade and the second blade. The whole height of the blade is adjusted by adjusting the distance between the two group blades, then the efficiency of the fan is improved effectively to optimize the noise level and the air flow.

A control circuit for changing the angle of propeller blades includes a propeller control unit controlling a supply of oil to modify an angle of propeller blades, and a fixed-displacement pump providing the supply of oil from an engine oil return system to the propeller control unit. An oil cooling line extends between an outlet of the pump and the engine oil return system. The oil cooling line defines an oil leakage path leading to the engine oil return system for cooling the oil. A flow regulator between the pump and the propeller control unit is operable between an open position where oil is directed through the oil cooling line to the engine oil return system for cooling the oil, and a closed position blocking the oil cooling line and directing oil toward the propeller control unit to modify the angle of the propeller blades.

An air moving device includes an outer casing comprising an outer diameter, an inner portion defining a flow path, an inlet portion defining an inlet cross-sectional area, and an opposing outlet portion defining an outlet cross-sectional area. A motor assembly is disposed within the outer casing, and a hub and blade assembly is secured to a shaft on the motor assembly. The air moving device further includes a de-swirl vane package. The package includes a plurality of de-swirl vanes disposed in the flow path. The blades are characterized by one or more resonant frequencies, and a potential excitation source of the blade resonant frequencies is a flow path obstruction comprising a plurality of objects substantially equally spaced about the circumference of the flow path. The flow path obstruction is characterized by a periodic frequency. The periodic frequency differs from the blade resonant frequencies by a safety margin of at least 20%.

A system for controlling operation of first and second electric fans is provided. The system includes a microcontroller that determines when first analog multiplexer is malfunctioning or a first channel of the first analog-to-digital converter is malfunctioning based on first values obtained from the first analog-to-digital converter. The first values are associated with at least one of a first speed signal associated with the first electric fan and a first driving voltage for the first electric fan that are received by the first analog multiplexer. The microcontroller modifies a control signal to induce the second electric fan to operate at a higher rotational speed when the first analog multiplexer is malfunctioning or the first channel of the first analog-to-digital converter is malfunctioning.

A gas turbine engine includes a compressor section including a first compressor, a turbine section including a first turbine and a second turbine, a first shaft and a second shaft, the first shaft interconnecting the first turbine and the second compressor, and a geared architecture. The first shaft is supported on a first bearing in an overhung manner. A performance ratio is between 0.5 and 1.5.

A valve includes a housing with a mounting portion, a venting portion, and a cap portion. The valve also includes a piston in the housing with a shaft, a disc, and a flange, the piston being moveable between a closed position and an open position. The valve also includes a vessel that is in contact with the cap portion and the flange wherein fluid pressure contained in the vessel biases the piston into one of the opened position and the closed position.

A blower includes a housing, a fan, a motor, and a speed regulator assembly including a switch for controlling the motor operation, a control member, and an actuating member both enabled to control the switch. The actuating member can move between an off state and an on state. The actuating member can move to a predefined limit position. The rotational speed of the motor corresponding to the predefined limit position is a predefined rotational speed. When the actuating member is in the off state, the motor stops running. When the actuating member is in the on state, the motor rotates. The control member has at least a first control state and a second control state. In the second control state, the motor runs at a maximum rotational speed. In the first control state, the motor runs at an intermediate speed lower than the maximum rotational speed.

A fan device includes a frame, a stability maintenance assembly, a shaft, an impeller, and a driving assembly. The frame includes a base and a bearing seat protruding from the base and having an accommodation space. The stability maintenance assembly is disposed in the accommodation space and includes a bearing and a magnet arranged coaxially. The bearing is located above the magnet and magnetized by the magnet. The shaft is disposed through the magnet and the bearing. The impeller is fixed to the shaft so as to be rotatable relative to the frame via the shaft and the bearing. The driving assembly includes a stator and a rotor. The stator is sleeved on the bearing seat of the frame, the rotor is mounted on the impeller and surrounds the stator, and the driving assembly is configured to drive the impeller to rotate relative to the frame.

A fan device includes a hub and a plurality of fan blades. Each of the fan blades includes a driving surface, and the driving surface includes a first tooth column and a second tooth column. The first tooth column includes a plurality of first skin-tooth units. Each of the first skin-tooth units includes a first body. A first middle ridge and two first side ridges protrude from a surface of the first body, and a groove is formed between two adjacent first skin-tooth units. The second tooth column includes a plurality of second skin-tooth units. Each of the second skin-tooth units includes a second body and an extension element. A second middle ridge and two second side ridges protrude from a surface of the second body, and the extension element is located in the groove and includes an extension rib.