Techniques for mechanical calibration of turbine overspeed trip are described. An electric motor rotates a rotational electric motor shaft coupled to an over speed trip collar of a rotational shaft of an electric machine at multiple rotational speeds. The over speed trip collar is configured to trip in response to the rotational electric motor shaft being rotated at a particular rotational speed. The over speed trip collar triggers an alarm when a rotational speed of the multiple rotational speeds substantially matches the particular rotational speed. The alarm provides a signal in response to triggering the alarm.

A gas turbine engine, includes: an engine core including a turbine, compressor, and shaft system connecting the turbine to the compressor, and forming a torque path therebetween. The shaft system is axially located by a thrust bearing located forward of the turbine, and the engine is configured, in the event of a shaft break which divides the shaft system into a front portion located by the thrust bearing and a rear portion unlocated by the thrust bearing, the rear portion is free to move axially rearwardly under a gas load. The engine further includes a shaft break detector having a forward speed sensor configured to measure a rotational speed of the front portion of the shaft system, and a rear microwave sensor configured to measure a rotational speed of the rear portion of the shaft system, wherein a shaft break can be detected based on differences in the measured speeds.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A cockpit in the airframe, the cockpit including two seats and a single collective control input positioned between the two seats.

An example system includes a gas-turbine configured to generate mechanical energy using fuel; an electrical generator configured to generate electrical energy using the mechanical energy generated by the gas-turbine; an electrical converter configured to process the electrical energy generated by the electrical generator; and a converter controller configured to reduce, responsive to detecting occurrence of a fault in the electrical generator or the electrical converter, an amount of fuel provided to the gas-turbine.

An aircraft is provided and includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe, at least one sensor and at least one inertial measurement unit (IMU) to sense current flight conditions of the aircraft, an interface to execute controls of a main rotor assembly in accordance with control commands and at least one flight control computer (FCC) to issue the control commands. The at least one FCC includes a central processing unit (CPU) and a memory having logic and executable instructions stored thereon, which, when executed, cause the CPU to issue the control commands based on the current flight conditions and a result of an execution of the logic for the current flight conditions.

Hybrid electric systems and methods therefore are provided. In one exemplary aspect, a hybrid electric system includes an engine, an electric machine operatively coupled thereto and configured to generate electrical power when driven by the engine. One or more electrical loads are electrically connectable with the electric machine. An engine controller of the engine receives load state data indicative of electrical loads that anticipate electrically disconnecting from or electrically connecting to the electric machine at a predetermined time. In this way, the engine controller can anticipate electrical load changes and the engine can be controlled to adjust its torque output in anticipation of the electrical load change. In another exemplary aspect, a hybrid electric system is provided that includes features for nearly instantaneously reacting to load changes on the engine based on load state data received from feed forward inputs of the electrical system of the hybrid electric system.

A turbine vane of a turbine engine is described. The turbine vane includes a blade and a root. The root includes a stilt having lateral flanks with a curvilinear profile. The stilt includes a frangible zone suitable for undergoing a breakage of the stilt if radial forces higher than a threshold are exerted on the vane, in particular centrifugal forces during an overspeed state of the turbine. The frangible zone includes at least one oblong frangibility recess formed on at least one of the lateral flanks of the stilt, the oblong recess extending in an axial direction of the stilt along a longitudinal axis parallel to or included in a minimum cross-sectional plane which contains a minimum cross-section of the stilt.

A dual trip manifold assembly (TMA) includes an isolation valve assembly having a first valve configured to receive a flow of fluid from a hydraulic system fluid supply. The first valve is configured to channel the flow of fluid to at least one hydraulic circuit. The isolation valve assembly also includes a second valve configured to receive the flow of fluid from the at least one hydraulic circuit of the at least two hydraulic circuits. The second valve is further configured to channel the fluid flow to a trip header and to receive the fluid flow from the trip header. The first valve and the second valve are synchronized to each other such that rotation of one of said first and second valves causes a substantially similar rotation in the other of said first and second valves header.

A gas turbine engine for an aircraft. The engine comprising: an engine core comprising a turbine, a compressor, a fan located upstream of the compressor and comprising a plurality of fan blades, and a core shaft connecting the turbine to the compressor; a gearbox which receives an input from the core shaft and outputs drive, via a driveshaft, to the fan so as to drive the fan at a lower rotational speed than the turbine, the drive shaft and core shaft forming a shaft system. The shaft system provides: a first portion which extends forward from a first thrust bearing to the fan, the first thrust bearing supporting the shaft system and being located between the turbine and the gearbox, and a second portion extending rearward from the first thrust bearing to the turbine, such that in the event of a shaft break within the second portion of the shaft system, said shaft break dividing the shaft system into a front portion axially located by the first thrust bearing and a rear portion no longer axially located by the first thrust bearing, the rear portion is free to move axially rearwardly under a gas load; and wherein the engine further comprises a shaft break detector, configured to detect a shaft break in the shaft system.

A retaining collar is disclosed for a bayonet mount comprising a rotor disc having a male mounting member defining a pair of apertures and an auxiliary annular wheel defining a plurality of mounting slots. The retaining collar comprises a ring-shaped body and a pair of retention pins. The ring-shaped body has a pair of circumferential end portions separated by a circumferential gap, and an arcuate radial outer surface extending circumferentially between the end portions. The body is dimensioned so that the radial outer surface frictionally engages a radial inner surface of a cylindrical male mounting member in the bayonet mount. The pair of retention pins each extend radially outward from one of the circumferential end portions. Each of the retention pins are dimensioned to extend radially outward from the body through one of said apertures and one of said mounting slots.