An engine system includes a turbine engine having a high pressure spool and a low pressure spool. A transmission includes an input shaft connected to one of the high pressure spool and the low pressure spool, and an output shaft. A clutch is arranged between the input shaft and the output shaft. A generator is connected to the output shaft. A clutch controller activates the clutch when one of the high pressure spool and the low pressure spool, and the generator are operating at a selected speed range.

In an asymmetric operating regime, a first engine is operating in an active mode to provide motive power to an aircraft while a second engine is operating in a standby mode and de-clutched from a gearbox of the aircraft. In response to an emergency exit request, the second engine’s speed is increased, at a maximum permissible rate, to a re-clutching speed while increasing the first engine’s power output at a maximum permissible rate. When the re-clutching speed is reached, the second engine’s power output is increased at a maximum permissible rate. In response to a normal exit request, the second engine’s speed is increased to the re-clutching speed at a rate lower than the maximum permissible rate. When the re-clutching speed is reached, the second engine’s power output is increased at a rate lower than the maximum permissible rate.

A fan assembly including a base arranged to support the fan assembly on a surface, an air flow generator that is arranged to generate an air flow, and an air outlet that is arranged to emit at least a portion of the air flow from the fan assembly is provided. The air outlet is arranged to be oscillated relative to the base. The fan assembly further includes a controller that is arranged to control the oscillation of the air outlet relative to the base. The controller is arranged to vary an oscillation speed of the air outlet for each oscillation.

An electronic controller for an engine and a propeller, a control system and related methods are described herein. The control system comprises the controller having a first channel and a second channel independent from and redundant to the first channel. Each channel comprises a control processor configured to receive first engine and propeller parameters and to output, based on the first engine and propeller parameters, at least one engine control command and at least one propeller control command. Each channel also comprises a protection processor configured to receive second engine and propeller parameters and to output, based on the second engine and propeller parameters, at least one engine protection command and at least one propeller protection command. The control system comprises sensors for measuring the parameters of the engine and/or the propeller and effectors configured to control the engine and the propeller.

A method (600) for testing control logic for a propeller driven by a gas turbine engine of an aircraft includes overriding (602) a signal indicating the aircraft is operating in a ground mode. The method can further include testing (604) minimum pitch protection logic when the signal is overridden; determining (606) the gas turbine engine is operating at a ground fine setting; restoring (608) the signal to an original state in which the signal indicates the aircraft is operating in the ground mode; modifying (610) pitch protection logic; determining (614) the propeller is operating at an overspeed condition; and testing (616) the propeller overspeed protection logic. In addition, the method can also determine (612) the propeller is operating at a low pitch condition when the gas turbine engine is operating at the ground fine setting.

Systems and methods are described herein for monitoring gas pressure within an electrolysis system and maintaining gas pressure using an electric generator to capture kinetic energy of compressed hydrogen and/or oxygen gases as they are produced by an electrolyzer. The generator utilizes a rotating apparatus, such as a fan or turbine, to capture the energy of the gases and generate electricity. Any electricity produced by the generator is fed back to the electrolyzer to supplement its energy requirements.

A system and method for generating input signals for an electronic engine control module includes a first waveform generator that is configured to generate a simulated first speed signal that is representative of a first speed and a vibration modulating signal that is representative of the first speed, a second waveform generator that is synchronized with the first waveform generator is configured to receive the vibration modulating signal and to generate a simulated second speed signal that is representative of a second speed and a simulated composite vibration voltage signal, and a voltage-to-charge converter that is configured to receive the simulated composite vibration voltage signal from the second waveform generator and to generate a simulated composite vibration charge signal that simulates a speed/vibration composite signal from an accelerometer.

Systems and methods to pump fracturing fluid into a wellhead may include a gas turbine engine including a compressor turbine shaft connected to a compressor, and a power turbine output shaft connected to a power turbine. The compressor turbine shaft and the power turbine output shaft may be rotatable at different rotational speeds. The systems may also include a transmission including a transmission input shaft connected to the power turbine output shaft and a transmission output shaft connected to a hydraulic fracturing pump. The systems may also include a fracturing unit controller configured to control one or more of the rotational speeds of the compressor turbine shaft, the power turbine output shaft, or the transmission output shaft based at least in part on target signals and fluid flow signals indicative of one or more of pressure or flow rate associated with fracturing fluid pumped into the wellhead.

A gas turbine engine includes, among other things, a fan, a fan drive gear system that is coupled with the fan and a fan drive input shaft, a compressor section that includes a first compressor and a second compressor, and a turbine section. The turbine section includes a first turbine coupled with a first shaft and a second turbine coupled through a second shaft to the second compressor. A bearing supports the fan drive input shaft. The bearing is located proximal to, and radially spaced from, a forward end of the first shaft. The bearing includes a speed sensor target that is rotatable with the forward end and that defines a rotation path. A speed sensor probe is situated proximal to the rotation path and is operable to read the speed sensor target.

Morphable rotor blades for a turbine engine systems include a root portion and an airfoil portion having a morphable portion including a morphable material that changes shape in response to a stimulus.