Method for monitoring the operation of a pair of turboprop engines of an aircraft comprising the steps of: detecting the sound pressure generated by the first or second turboprop engine generating a respective first or second signal x(t); iteratively calculating by means of a function Rx/Ry the similarity between the first/second signal x(t)/y(t) at a time T1 and at a time T2 subsequent to time T1; and storing the degrees of similarity calculated in successive iterations in order to detect situations of normal operation of the engines when the degrees of similarity fall in successive iterations within the interval of a first value and to detect a potential fault situation in the engines when the degrees of similarity depart from this interval.

A gas turbine engine generates noise during use, and one particularly important flight condition for noise generation is take-off. A gas turbine engine that has high efficiency provides low noise, in particular from the fan and the turbine that drives the fan. Values are defined for a noise parameter NP that results in a gas turbine engine having reduced combined fan and turbine noise.

There is provided a turbofan engine having: a fan rotatable about an axis within a case; a first acoustic treatment lining a first portion of the case upstream of the fan; and a second acoustic treatment lining a second portion of the case downstream of the fan, the first acoustic treatment having different noise-attenuating characteristics relative to the second acoustic treatment.

Embodiments of the present disclosure include a method for controlling a power generation system, the method including: detecting a heat distribution across a component of a power generation system from a thermal output of the component, during operation of the power generation system; calculating a projected heat distribution across the component based on a library of modeling data for the power generation system; calculating whether a difference between the heat distribution and the projected heat distribution exceeds a thermal threshold; adjusting the power generation system in response to the difference exceeding the predetermined threshold, wherein the adjusting includes modifying an operating setting of the power generation system.

A gas turbine engine generates noise during use, and one particularly important flight condition for noise generation is take-off. A gas turbine engine that has high efficiency provides low noise, in particular from the fan and the turbine that drives the fan. Values are defined for a noise parameter NP that results in a gas turbine engine having reduced combined fan and turbine noise.

Disclosed herein is a method of automatically determining an operating condition of at least part of a gas turbine engine 10 for an aircraft, the method comprising: measuring one or more gas pressure waves by a gas pressure detector 401, wherein the gas pressure detector 401 is located in the gas turbine engine 10; and automatically determining, by a computing system, an operating condition of at least part of a gas turbine engine 10 in dependence on an output signal of the gas pressure detector 401.

An aircraft propulsion system comprises first and second thrust producing gas turbine engines. The system comprises a controller configured to determine a required overall propulsion system thrust level, and determine an engine core power level contribution from each aircraft gas turbine engine such that the overall propulsion system produces a minimum overall noise level and meets the required overall propulsion system thrust level. In meeting the minimum overall noise level, at least the first and second gas turbine engines are operated at different engine core power settings.

A bearing arrangement includes a shaft, at least one contact bearing and at least one non-contact bearing and a controller. The controller is configured to control a magnitude of a restoring force applied to the shaft by the non-contact bearing in accordance with a sensed parameter such that a stiffness of the shaft is modified such that one or more resonance frequencies of the shaft are moved away from one or more external forcing frequencies.

A blower and a method for decreasing eddy noise are provided. The blower includes a fan frame, a fan wheel, at least one induction element and a coil. The fan frame has in inlet and an outlet. The fan wheel is disposed in the fan frame and has a wheel hub and a plurality of fan blades connected to periphery of the wheel hub. The induction elements are fixed to the corresponding fan blades, the coil is disposed on the fan frame for driving the at least one induction element, such that the fan blade corresponding to the induction element swing back and forth to generate a vibration sound, and the vibration sound is counteracted with eddy noise generated when the fan wheel rotates. Moreover, the method for decreasing eddy noise is also provided.

A method is provided for carrying out a sound test for detecting and/or analyzing material faults and/or mounting faults of at least one component, in which the component is excited, by striking, to experience vibrations which generate soundwaves, after which the generated soundwaves are detected and conclusions are drawn about material faults and/or mounting faults on the basis of the detected soundwaves, wherein the striking of the component and the detection of the vibrations are carried out using an endoscope device. In addition, embodiments of the present invention relates to an endoscope device which is configured to carry out the method.