Abstract: An air interface plane (AIP) of a radio frequency (RF) aperture includes: a circuit board having a first side and a second side opposite the first side; and a matrix of tapered elements arranged on the first side of the circuit board and secured to the circuit board, the matrix of tapered elements cooperating to at least one of receive or transmit an over-the-air RF signal. Suitably, each tapered element of the matrix has: a central hub extending along a longitudinal axis from a hub base which is proximate to the first side of the circuit board to an apex of the tapered element which is distal from the first side of the first circuit board; and a plurality of arms extending from the central hub at the apex of the tapered element, each of the plurality of arms including a first portion that projects the arm radially away from the longitudinal axis and a second portion that projects the arm longitudinally toward the first side of the circuit board.

Abstract: A power-generation system for a nuclear reactor includes a power unit, a heat exchanger, and a temperature control system. The power unit produces compressed air that is heated by the nuclear reactor via the heat exchanger. The temperature control system includes a heat transfer fluid and a heat exchanger fluidly connected with the compressed air to transfer heat between the compressed air and heat transfer fluid to control the power level of the power unit.

Abstract: A power-generation system for a nuclear reactor includes a power unit, a heat exchanger, and a temperature control system. The power unit produces compressed air that is heated by the nuclear reactor via the heat exchanger. The temperature control system includes a heat transfer fluid and a heat exchanger fluidly connected with the compressed air to transfer heat between the compressed air and heat transfer fluid to control the power level of the power unit.

Abstract: A power generation system for a nuclear reactor includes an externally-heated turbine engine, a reactor heat exchanger, and a heat recuperating system. The externally-heated turbine engine produces compressed air that is heated by the reactor heat exchanger. The heat recuperating system includes a heat exchanger thermally connected to the externally-heated turbine engine to transfer heat to the compressed air to supplement the reactor heat exchanger.

Abstract: A power generation system for a nuclear reactor includes an externally-heated turbine engine, a reactor heat exchanger, and a heat recuperating system. The externally-heated turbine engine produces compressed air that is heated by the reactor heat exchanger. The heat recuperating system includes a heat exchanger thermally connected to the externally-heated turbine engine to transfer heat to the compressed air to supplement the reactor heat exchanger.

Abstract: A power-generation system for a nuclear reactor includes a power unit, a heat exchanger, and a temperature control system. The power unit produces compressed air that is heated by the nuclear reactor via the heat exchanger. The temperature control system includes a heat transfer fluid and a heat exchanger fluidly connected with the compressed air to transfer heat between the compressed air and heat transfer fluid to control the power level of the power unit.

Abstract: A method for cooling a hybrid electric aircraft propulsion system comprises transporting a coolant through a two-phase pumped loop (TPPL) in thermal contact with an electrical machine and a plurality of power modules to be cooled, where the TPPL includes: a parallel arrangement of cold plates; an evaporator; a condenser; a first control valve; a liquid receiver; and a pump. A sensor positioned upstream of the cold plates, and in some cases upstream of the liquid receiver, measures pressure and/or temperature of a return stream of the coolant and transmits measurement data to a first controller electrically connected to the first control valve. The first controller regulates flow of a first liquid stream through the first control valve based on the pressure and/or temperature measured by the sensor, thereby keeping the return stream at a temperature within a predetermined temperature range.

Abstract: A cooling system may include a cooling pump, a cooling source, a thermal energy storage, a mixing valve, a recharge valve, a recharge pump. The mixing valve may be in fluid communication with a thermal load. A first input of the mixing valve may be in fluid communication with the thermal energy storage. A second input of the mixing valve may be in fluid communication with the recharge pump. Operation of the recharge pump may cause heated cooling fluid output from the thermal load to bypass the cooling pump and flow to the second input of the mixing valve. The recharge valve may be in fluid communication with the thermal energy storage and the cooling pump. The recharge valve may regulate a recharge fluid flow comprising cooling fluid received from the thermal energy storage.

Abstract: A cooling system may include a cooling pump that causes cooling fluid received from a thermal load to flow to a cooling source, a low-load valve, a high-load valve, a thermal energy store, and a mixing valve. The cooling source and the low-load valve may be downstream from the cooling pump. The high load valve and thermal energy storage may be downstream from the cooling source. The first input of the mixing valve may be downstream from the thermal energy storage. The second input of the mixing valve may be downstream from the low-load valve and the high-load valve. The thermal load may be downstream from an output of the mixing valve. The cooling system may switch between a low load mode and a high load mode with coordinated operation of the low-load valve and high-load valve.

Abstract: A cooling system may include a cooling pump, a cooling source, a thermal energy storage, a mixing valve, a recharge valve, a recharge pump. The mixing valve may be in fluid communication with a thermal load. A first input of the mixing valve may be in fluid communication with the thermal energy storage. A second input of the mixing valve may be in fluid communication with the recharge pump. Operation of the recharge pump may cause heated cooling fluid output from the thermal load to bypass the cooling pump and flow to the second input of the mixing valve. The recharge valve may be in fluid communication with the thermal energy storage and the cooling pump. The recharge valve may regulate a recharge fluid flow comprising cooling fluid received from the thermal energy storage.

Abstract: A cooling system may include a cooling pump that causes cooling fluid received from a thermal load to flow to a cooling source, a low-load valve, a high-load valve, a thermal energy store, and a mixing valve. The cooling source and the low-load valve may be downstream from the cooling pump. The high load valve and thermal energy storage may be downstream from the cooling source. The first input of the mixing valve may be downstream from the thermal energy storage. The second input of the mixing valve may be downstream from the low-load valve and the high-load valve. The thermal load may be downstream from an output of the mixing valve. The cooling system may switch between a low load mode and a high load mode with coordinated operation of the low-load valve and high-load valve.

Abstract: A cooling system for a gas turbine is provided that may include a drive shaft, a shield of a combustor of the gas turbine engine, and a conduit. The drive shaft may be configured to mechanically couple a compressor of the gas turbine engine to a turbine of the gas turbine engine. The shield may be positioned between the compressor and the turbine. The combustor may be configured to drive the turbine. The conduit may be configured to supply a cooling fluid to a gap between an outer surface of the drive shaft and the shield of the combustor.

Abstract: A cooling system for a gas turbine is provided that may include a drive shaft, a shield of a combustor of the gas turbine engine, and a conduit. The drive shaft may be configured to mechanically couple a compressor of the gas turbine engine to a turbine of the gas turbine engine. The shield may be positioned between the compressor and the turbine. The combustor may be configured to drive the turbine. The conduit may be configured to supply a cooling fluid to a gap between an outer surface of the drive shaft and the shield of the combustor.

Abstract: A turbofan gas turbine engine includes a first shaft for mounting and rotation of a fan, the first shaft including a single stage internal gear mounted on the first shaft aft of the fan. The turbofan engine further includes a second shaft for mounting and rotation of a low pressure compressor and a low pressure turbine, the second shaft including a pinion gear mounted thereon forward of the low pressure compressor. The pinion gear meshes with the single stage internal gear to drive the first shaft and fan. The second shaft is parallel and off-set from the first shaft.

Abstract: A gas turbine engine valve is disclosed. In one form the valve includes two inlets in fluid communication with an outlet. The valve can include a spool having two lands capable of selectively closing either of the two inlets. The valve can include energy storage devices that initially position the spool within a valve housing. A temperature motor is provided to position the spool based upon a temperature of a mixture of working fluid from the two inlets. A working fluid flowing into the first inlet can be in fluid communication with a second end of the valve; and a working fluid flowing into the second inlet can be in fluid communication with a first end of the valve. A relatively high pressure condition at one or the other of the inlets can be used to alter a position of the valve.

Abstract: A gas turbine engine valve is disclosed. In one form the valve includes two inlets in fluid communication with an outlet. The valve can include a spool having two lands capable of selectively closing either of the two inlets. The valve can include energy storage devices that initially position the spool within a valve housing. A temperature motor is provided to position the spool based upon a temperature of a mixture of working fluid from the two inlets. A working fluid flowing into the first inlet can be in fluid communication with a second end of the valve; and a working fluid flowing into the second inlet can be in fluid communication with a first end of the valve. A relatively high pressure condition at one or the other of the inlets can be used to alter a position of the valve.