Abstract: An example system includes an electrical machine electrically configured to generate electrical energy used by one or more components of a gas-turbine engine; an energy storage system; and a controller electrically connected to the energy storage system and configured to receive electrical energy from the energy storage system, wherein, in response to the gas-turbine engine being shut off, the controller is configured to cause the electrical machine to rotate a rotor of the gas-turbine engine using the energy received from the energy storage system.

Abstract: An example system includes one or more heaters configured and positioned to add thermal energy to one or more portions of a gas turbine engine after the gas turbine engine was in operation, wherein the thermal energy minimizes or prevents undesired contact or seizing of a rotor of the gas turbine engine with another component of the gas turbine engine due to warping of the rotor due to uneven cooling of the gas turbine engine after the operation. The system further includes a controller configured to control operation of the one or more heaters.

Abstract: In examples, a clutch assembly includes a first clutch member disposed near a first end of a first shaft. The first clutch member defines a first surface. The first shaft includes a starter motor coupled to a second end of the first shaft. The clutch assembly includes a second clutch member disposed near a first end of a second shaft. The second clutch member defines a second surface opposing the first surface, and the second shaft includes an accessory gearbox of a gas turbine engine coupled to a second end of the second shaft. The surfaces of the first and second clutch member engage such that rotational motion is transferred between the first clutch member and the second clutch member. The first clutch member and the second clutch member are configured to passively disengage from each other and actively reengage with each other.

Abstract: An example system includes a first gas-turbine engine (GTE) of a plurality of GTEs that are configured to propel an aircraft, the first GTE comprising: a first air-turbine starter (ATS) of a plurality of ATSs, the first ATS configured to rotate a spool of the first GTE; and a first electric starter of a plurality of electric starters, the first electric starter configured to rotate the spool of the first GTE; a second GTE of the plurality of GTEs, the second gas-turbine engine comprising: a second ATS of the plurality of ATSs, the second ATS configured to rotate a spool of the GTE; and a second electric starter of the plurality of electric starters, the second electric starter configured to rotate the spool of the GTE; and one or more controllers configured to control the plurality of GTEs.

Abstract: A system includes a gas turbine engine configured to provide propulsion to an aircraft and a starter system configured to start the gas turbine engine. The starter system comprises a motor controller and a closed-loop cooling system configured to cool the motor controller during an emergency in-flight restart operation of the gas turbine engine. The closed-loop cooling system includes a cooling fluid reservoir containing cooling fluid. The cooling fluid is configured to receive thermal energy from the motor controller during the emergency in-flight restart operation of the gas turbine engine.

Abstract: An example system includes a first gas-turbine engine configured to propel an aircraft, the first gas-turbine engine comprising: a first air-turbine starter, the first air-turbine starter configured to rotate a spool of the first gas-turbine engine; and a first electric starter, the first electric starter configured to rotate the spool of the first gas-turbine engine; and one or more controllers collectively configured to: cause, during a time period, the first-air turbine starter and the first electric starter to start the first gas-turbine engine while the aircraft is on the ground; measure, during the time period, values of one or more parameters of the first gas-turbine engine; and determine, based on the values of the one or more parameters, whether the first electric starter is available for use in performing mid-air restart of the first gas-turbine engine.

Abstract: A starting apparatus for a gas turbine engine of a plurality of gas turbine engines of an aircraft. The apparatus includes a fuel supply system, a combustor, and a controller. The controller is configured to cause fuel to be introduced to the combustor of the gas turbine engine at a first threshold rotational speed of the gas-turbine engine during a normal starting operation in which the aircraft is on the ground. The controller is configured to cause fuel to be introduced to the combustor at a second threshold rotational speed of the gas-turbine engine during an emergency in-flight restarting operation in which the aircraft is in-flight. The second threshold rotational speed is lower than the first threshold rotational speed. Introducing fuel at the second threshold rotational speed results in a higher temperature in a turbine of the gas turbine engine than introducing fuel at the first threshold rotational speed.

Abstract: A starting apparatus for a first gas turbine engine of a plurality of gas turbine engines of an aircraft. The apparatus includes an air turbine starter, an electric machine, and a controller. The controller is configured to receive an emergency restart command for the first gas turbine engine while the aircraft is in-flight, determine whether the first gas turbine engine is in operation, determine whether at least a second gas turbine engine of the plurality of gas turbine engines is in operation, and, responsive to receiving the emergency restart command and determining that at least the second gas turbine engine of the plurality of gas turbine engines is in operation and that the first gas turbine engine is not in operation, perform an emergency restart of the first gas turbine engine.

Abstract: A battery pack core may include a cold plate comprising a plurality of apertures defined between a first major surface and a second major surface of the cold plate; a plurality of battery cells, a single battery cell positioned in each aperture of the plurality of apertures such that a first end of the battery cell projects beyond the first major surface and a second end of the battery cell projects beyond the second major surface; and a plurality of silicone bushings, a silicone bushing surrounding each battery cell of the plurality of battery cells and contacting a wall of the aperture in which the battery cell is positioned.

Abstract: A rotor assembly for an electric machine includes a rotor segment configured to rotate about an axis and having a rotor body, a side wall and an outer band that cooperate to form a cavity, a plurality of magnets located in the cavity, and an end plate configured to block the plurality of magnets within the cavity.

Abstract: An example system includes one or more heaters configured and positioned to add thermal energy to one or more portions of a gas turbine engine after the gas turbine engine was in operation, wherein the thermal energy minimizes or prevents undesired contact or seizing of a rotor of the gas turbine engine with another component of the gas turbine engine due to warping of the rotor due to uneven cooling of the gas turbine engine after the operation. The system further includes a controller configured to control operation of the one or more heaters.

Abstract: An example system includes a thermal energy system configured to transport thermal energy harvested from a first portion of a gas turbine engine to a second portion of the gas turbine engine after the gas turbine engine was in operation, wherein the transported thermal energy minimizes or prevents undesired contact or seizing of a rotor with another component of the gas turbine engine due to warping of the rotor due to uneven cooling of the gas turbine engine after the operation. The thermal energy system includes a cavity configured to flow a fluid, wherein the fluid is configured to transport thermal energy from the first portion to the second portion.

Abstract: An example system includes a common electric starter controller configured to control electric starters of a plurality of gas-turbine engines that are configured to propel an aircraft, wherein the common electric starter comprises: a driver configured to generate, using electrical energy sourced from a battery of the aircraft, power signals that control the electric starters; and a plurality of bus bars configured to directly connect the common electric starter controller to the battery and transport the electrical energy from the battery to the common electric starter controller.

Abstract: In examples, a clutch assembly includes a first clutch member disposed near a first end of a first shaft. The first clutch member defines a first surface. The first shaft includes a starter motor coupled to a second end of the first shaft. The clutch assembly includes a second clutch member disposed near a first end of a second shaft. The second clutch member defines a second surface opposing the first surface, and the second shaft includes an accessory gearbox of a gas turbine engine coupled to a second end of the second shaft. The surfaces of the first and second clutch member engage such that rotational motion is transferred between the first clutch member and the second clutch member. The first clutch member and the second clutch member are configured to passively disengage from each other and actively reengage with each other.

Abstract: A rotor assembly includes a rotor core having an axial length and configured to rotate about a longitudinal axis and at least one permanent magnet disposed about a radially outer surface of the rotor core. The rotor assembly further includes an electrical insulator disposed between the radially outer surface of the rotor core and the at least one permanent magnet and configured to disrupt an electrical conduction path along the axial length of the rotor core.

Abstract: A propulsion system for an aircraft includes a propeller assembly, a controller, and a pump system. The propeller assembly includes a propeller and a power system, the power system including an electric motor and a motor converter. The controller is connected to the power system and configured to switch the power system into a power-off arrangement in response to a temperature of the motor converter being greater than a threshold temperature. The pump system includes a pump and a coolant circuit that cools the motor converter. The pump is coupled to the propeller and to the motor such that rotation of either drives the pump.

Abstract: A voltage controlled aircraft electric propulsion system includes an electric propulsion system. The voltage controlled aircraft electric propulsion system may include electric propulsors providing thrust for the aircraft. In hybrid systems, a gas turbine engine may also be included. The electric propulsion system may include at least one electric generator power source, at least one propulsor motor load, and at least one stored energy power source, such as a battery. The propulsor motor load may be supplied power from a power supply bus. The voltage of the power supply bus may be adjusted according to an altitude of the aircraft while maintaining a substantially constant current flow to the propulsor motor load. Due to the adjustment to lower voltages at increased altitude, insulations levels may be lower.

Abstract: An example system includes a power electronics system; a starter electrically connected to the power electronics system and configured to start a gas-turbine engine of an aircraft; and an energy storage system electrically connected to the power electronics system and configured to provide direct current (DC) electrical energy to the power electronics system, wherein the power electronics system is configured to deliver alternating current (AC) electrical energy to the starter to start the gas-turbine engine using the DC electrical energy from the energy storage system and AC electrical energy sourced from an AC electrical bus of the aircraft.

Abstract: An example system includes an electrical machine electrically configured to generate electrical energy used by one or more components of a gas-turbine engine; an energy storage system; and a controller electrically connected to the energy storage system and configured to receive electrical energy from the energy storage system, wherein, in response to the gas-turbine engine being shut off, the controller is configured to cause the electrical machine to rotate a rotor of the gas-turbine engine using the energy received from the energy storage system.

Abstract: A drill chuck having a chuck body connectable to a drill spindle, in which clamping jaws are arranged in guide receptacles which run at an incline to the chuck axis and, for the purpose of opening and closing, are adjustable by a threaded ring arranged so as to be rotatable and axially immovable with respect to the chuck body. A locking device, which is made up of a coaxial circle of locking recesses and of at least one locking member, is engaged with the locking recesses under the force of a locking spring. A locking adjusting, is rotatable to a limited extent between end stops and whose rotation allows the locking member to be adjusted. A latching device forms two latching positions in the circumferential direction. A dampener is arranged between the adjusting sleeve and the component adjacent thereto radially to the inside.