A gas turbine engine comprises a fan at an axially outer location, the fan rotating about an axis of rotation, delivering air into an outer bypass duct, a radially middle duct, and a radially inner core duct. Air from the inner core duct is directed into a compressor, and then flows axially in a direction back toward the fan through a combustor section, and across a core turbine section, and is then directed into the middle duct. A gear reduction drives the fan from a fan drive turbine section. A method of operating a gas turbine engine is also disclosed.

A method of making a rotor assembly of a turbojet includes building the rotor assembly via layer-by-layer additive manufacturing. A turbine portion is formed and a compressor portion is integrally formed with the turbine portion. A shaft portion is integrally formed with the compressor portion. A material of the rotor assembly includes a nickel based alloy.

A method of making a rotor assembly of a turbojet includes building the rotor assembly via layer-by-layer additive manufacturing. A turbine portion is formed and a compressor portion is integrally formed with the turbine portion. A shaft portion is integrally formed with the compressor portion. A material of the rotor assembly includes a nickel based alloy.

An exoskeletal gas turbine engine having a rotatable outer shaft and an inner stationary case enclosed in a casing. The engine comprises a compressor section at an inlet end, a combustor section, and a turbine section at an outlet end. Rotating compressor blades and turbine blades are attached to, and extend radially inward from, an inner surface of the outer shaft. Stationary vanes are attached, and extend radially outward from, an outer surface of the inner stationary case. The outer shaft rotates around a front bearing and a rear bearing. An inlet compressor blade arrangement is attached to the outer race of the front bearing. An outlet turbine blade arrangement is attached to the outer race of the rear bearing. The inner race of the front and rear bearings attach to the inner stationary case.

An exoskeletal gas turbine engine having a rotatable outer shaft and an inner stationary case enclosed in a casing. The engine comprises a compressor section at an inlet end, a combustor section, and a turbine section at an outlet end. Rotating compressor blades and turbine blades are attached to, and extend radially inward from, an inner surface of the outer shaft. Stationary vanes are attached, and extend radially outward from, an outer surface of the inner stationary case. The outer shaft rotates around a front bearing and a rear bearing. An inlet compressor blade arrangement is attached to the outer race of the front bearing. An outlet turbine blade arrangement is attached to the outer race of the rear bearing. The inner race of the front and rear bearings attach to the inner stationary case.

A compressor vane is provided. The compressor vane may include a first surface directed toward air introduced into a compressor, a second surface directed in a direction opposite to the first surface, and two tangent lines in which the first and second surfaces meet, wherein a rate of change, with respect to a height of the compressor vane, of a maximum separation distance, between the first surface and the second surface, divided by a distance from one to the other of the two tangent lines in a cross-section at one position of the height of the compressor vane in a direction starting from a portion of the compressor vane closest to a center tie rod and toward a compressor housing varies with the height of the compressor vane away from the portion of the compressor vane closest to the center tie rod.

A compressor vane is provided. The compressor vane may include a first surface directed toward air introduced into a compressor, a second surface directed in a direction opposite to the first surface, and two tangent lines in which the first and second surfaces meet, wherein a rate of change, with respect to a height of the compressor vane, of a maximum separation distance, between the first surface and the second surface, divided by a distance from one to the other of the two tangent lines in a cross-section at one position of the height of the compressor vane in a direction starting from a portion of the compressor vane closest to a center tie rod and toward a compressor housing varies with the height of the compressor vane away from the portion of the compressor vane closest to the center tie rod.

A gas turbine engine comprises at least a power output turbine unit (POT), which is rotatably arranged inside an outer housing unit, and a compressor-turbine unit (CTU), which is rotatably arranged inside the POT, and the CTU, POT and outer housing unit are arranged about a common axis of rotation (CL). The POT and the CTU are arranged in such close proximity (d) that a dynamic friction coupling is generated between the POT and the CTU.

A gas turbine engine comprises at least a power output turbine unit (POT), which is rotatably arranged inside an outer housing unit, and a compressor-turbine unit (CTU), which is rotatably arranged inside the POT, and the CTU, POT and outer housing unit are arranged about a common axis of rotation (CL). The POT and the CTU are arranged in such close proximity (d) that a dynamic friction coupling is generated between the POT and the CTU.

A gas turbine engine includes a rotatable first shaft, a first disk connected to the first shaft, a second disk connected to the first shaft, a combustor radially outward from the first disk and the second disk, and a heat exchanger connected to the combustor aft of the second disk. The first disk includes a row of low pressure compressor blades and a row of high pressure turbine blades connected to a radially outer end of the row of low pressure compressor blades. The second disk includes a row of high pressure compressor blades and a row of low pressure turbine blades connected to a radially outer end of the row of high pressure compressor blades.