One example aspect of the present disclosure is directed to a method for measuring engine performance. The method includes receiving a plurality of parameters related to engine performance. The method includes receiving an indication of an engine wash event. The method includes determining an effectiveness of the engine wash event based on the plurality of parameters. The method includes performing a comparison of the effectiveness of the engine wash event with an expected effectiveness of the engine wash event. The method includes performing a control action based on the comparison.

According to an aspect, a system for a gas turbine engine includes a reduction gear train operable to drive rotation of a starter gear train that interfaces to an accessory gearbox of the gas turbine engine. The reduction gear train includes a starter interface gear that engages the starter gear train, a core-turning clutch operably connected to the starter interface gear, and a plurality of stacked planetary gear systems operably connected to the core-turning clutch and a core-turning input. The system also includes a mounting pad including an interface to couple a core-turning motor to the core-turning input of the reduction gear train.

A turbomachine engine can include a fan assembly, a pitch change mechanism, a vane assembly, a core engine, a gearbox, and a gearbox efficiency rating. The fan assembly can include a plurality of fan blades. The pitch change mechanism can be coupled to the fan assembly. The vane assembly can include a plurality of vanes. The core engine can include one or more compressor sections and one or more turbine sections. The gearbox includes an input and an output. The input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, the output is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 4.1-14.0. The gearbox efficiency rating is 0.10-1.8.

An air cycle machine for extracting bleed air from a gas turbine engine of an aircraft is provided. The air cycle machine extracts a stream of low pressure bleed air and a stream of high pressure bleed air from a compressor section of the gas turbine engine. The air cycle machine includes a compressor that receives the stream of low pressure bleed air and a turbine that receives the stream of high pressure bleed air. The stream of high pressure bleed air is expanded as it drives the turbine, and the stream of low pressure bleed air is compressed by the compressor. The resulting streams of bleed air are substantially the same pressure, such that they may be merged using a junction into a combined bleed air stream having a temperature and pressure suitable for use by a variety of aircraft accessory systems, such as an environmental control system. The air cycle machine may further power or be powered from an electrical storage device or generator on the fan.

The present application discloses a method of determining one or more fuel characteristics of an aviation fuel suitable for powering a gas turbine engine of an aircraft. The method comprises: determining, during use of the gas turbine engine, one or more exhaust content parameters by performing a sensor measurement on an exhaust of the gas turbine engine; and determining one or more fuel characteristics of the fuel based on the one or more exhaust parameters. Also disclosed is a fuel characteristic determination system, a method of operating an aircraft, and an aircraft.

Discharge grate intended to be mounted inside or at the outlet of a conduit of a discharge valve of a turbine engine of an aircraft, the discharge grate comprising an upstream face intended to receive a gas flow, a downstream face parallel to the upstream face and intended to deliver the gas flow received on the upstream face, and orifices passing through the perforated plate from the upstream face to the downstream face and intended to convey the gas flow through the perforated plate. The discharge grate comprises for each orifice of the perforated plate a tubular channel, coaxial with the orifice with which it is associated, and projecting from the downstream face of the perforated plate.

Turbines and associated equipment are normally cleaned via water or chemical pressure washing via a mist, spray systems. However, these systems fail to reach deep across the gas path to remove fouling materials. Various embodiments herein pertain to apparatus and methods that utilize the water and exiting chemicals to generate a foam. The foam can be introduced at that gas-path entrance of the equipment, where it contacts the stages and internal surfaces to contact, scrub, carry, and remove fouling away from equipment to restore performance.

A rotor blade system includes a blade root, a blade neck adjoining the blade root, an airfoil adjoining the blade neck, a radially outer partition wall, an axially forward partition wall and an axially rearward partition wall, connected to the radially outer partition wall such that the partition walls surround the blade neck on three sides, the partition walls projecting beyond the blade neck in the circumferential direction, and further including a blade root protection plate designed to be arranged on the blade root. It is provided that the blade root protection plate have at least one sealing portion that extends in the axial direction from the forward partition wall to the rearward partition wall and whose radially outer side is disposed opposite the radially outer partition wall when the blade root protection plate is arranged on the blade root.

A fan casing for an engine having a fan with fan blades that each have a centre of gravity (CoG) that lies on a fan blade CoG plane, the fan casing having a central axis and comprising a main impact region comprising carbon-fibre reinforced polymer (CFRP) blocks and glass-fibre reinforced polymer (GFRP) blocks having a constant thickness throughout the axial extent of the main impact region, wherein the total depth of the main impact region is equal to the sum of the thicknesses of the CFRP blocks and GFRP blocks, each of the GFRP blocks is positioned between two CFRP blocks, and the thickness of at least one of the GFRP blocks is different to the thickness of another of the GFRP blocks.

A gas turbine engine comprises a bypass duct and a heat exchanger assembly, the heat exchanger assembly comprising a heat exchanger and a heat exchanger duct having an inlet region, an inflection region and an outlet region. A direction of a centreline of the heat exchanger duct has a tangential component with respect to a principal rotational axis of the gas turbine engine at one or more of the inlet region, the inflection region and the outlet region. The heat exchanger is disposed within the inflection region and configured to transfer heat generated by the gas turbine engine into the flow of air as it passes through the inflection region.