This invention discloses an improved wind turbine suitable for mounting without a wind turbine tower. The wind turbine is based on a rotor with appropriately selected blades. A nozzle and diffuser in the wind flow increase the amount of wind energy available to the rotor. One or more wind turbines can be grouped together in a common housing. The lack of a wind turbine tower and the general compact design allows the wind turbine to be used in close proximity to or on buildings.

Methods and systems are provided for a branch communication valve in a twin turbocharger system. A branch communication valve may be positioned adjacent to a dividing wall separating a first scroll and a second scroll of the twin turbocharger. In an open position, the branch communication valve increases fluid communication between the first scroll and the second scroll and in a closed position, the branch communication valve decreases fluid communication between the first scroll and the second scroll.

A first electrical machine is operated according to a first mode and a second electrical machine is operated according to a second mode. A power split of operation of the first electrical machine and the second electrical machine is determined. The operation of the first electrical machine and the second electrical machine are controlled according to the power split. The power split is optimized to protect operating constraints of the components of the engine and the aircraft while delivering required thrust to the aircraft.

A compressor vane is provided. The compressor vane may include a first surface directed toward air introduced into a compressor, a second surface directed in a direction opposite to the first surface, and two tangent lines in which the first and second surfaces meet, wherein a rate of change, with respect to a height of the compressor vane, of a maximum separation distance, between the first surface and the second surface, divided by a distance from one to the other of the two tangent lines in a cross-section at one position of the height of the compressor vane in a direction starting from a portion of the compressor vane closest to a center tie rod and toward a compressor housing varies with the height of the compressor vane away from the portion of the compressor vane closest to the center tie rod.

A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

A system is provided for alternating starter use during multi-engine motoring in an aircraft. The system includes a first engine starting system of a first engine. A first controller is in communication with a second controller that controls a second engine starting system of a second engine, the first controller being configured to intermittently direct power to the first engine starting system to alternately accelerate and decelerate the first engine during motoring with respect to the second engine.

A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

Embodiments of the disclosure are directed to a ducted fan engine configured for providing thrust for an aircraft, in particular an aircraft having vertical take-off and landing capability. The ducted fan engine includes a shroud, a stator, and a rotor rotatably supported by the shroud. The shroud has a substantially circular cross-section. The stator has at least one substantially radially-extending stator vane. The rotor comprises at least 19 rotor blades, in particular at least 25 rotor blades.

A geared turbofan engine includes a first rotor, a fan, a second rotor, a gear train, a fan casing, a nacelle and a plurality of discrete acoustic liner segments. The fan is connected to the first rotor and is capable of rotation at frequencies between 200 and 6000 Hz and has a fan pressure ratio of between 1.25 and 1.60. The gear train connects the first rotor to the second rotor. The fan casing and nacelle are arranged circumferentially about a centerline and define a bypass flow duct in which the fan is disposed. The plurality of discrete acoustic liner segments with varied geometric properties are disposed along the bypass flow duct.

A combustor of an embodiment includes: a cylindrical combustor liner; and a fuel nozzle which is provided at one end of the combustor liner and jets a fuel and an oxidant into the combustor liner. The fuel nozzle includes: a plurality of fuel supply passages which each supply the fuel; and a plurality of oxidant supply passages which each supply the oxidant. Flow rates of the fuel supplied to the respective fuel supply passages and flow rates of the oxidant supplied to the respective oxidant supply passages are each individually regulated.