An assembly is provided for a gas turbine engine. This assembly includes a rotating structure, a stationary structure and a bushing. The rotating structure extends axially along and is rotatable about a centerline. The stationary structure extends circumferentially about the rotating structure. The stationary structure is configured from or otherwise includes stationary structure material with a coefficient of thermal expansion between 10 μin/in-° F. and 15 μin/in-° F. The bushing is radially between the rotating structure and the stationary structure. The bushing includes a mount and a bearing within the mount. The mount is configured from or otherwise includes mount material with a coefficient of thermal expansion between 9 μin/in-° F. and 10 μin/in-° F. The mount material contacts the stationary structure material. The bearing is configured from or otherwise includes bearing material, where the bearing material is engaged with and rotatably supports the rotating structure. The bearing material is or otherwise includes copper.

A turboramjet has a housing with an intake and an exhaust. The housing houses a heat exchanger, a turbojet section and a ramjet section downstream of the turbojet section. The heat exchanger has an air path and a coolant path. The air path is configured to receive air from the air intake. The heat exchanger has a first section made from a first material and a second section made from a second material, the second material having a lower melting point and a lower density relative to the first material. A bypass air passage selectively bypasses the turbojet section to supply air to the ramjet section, and the coolant path uses fuel as a coolant and is configured to supply the fuel to the turbojet section.

Exhaust redirecting devices are described that are suitable for use in tilt rotor aircraft. Such devices are constructed of light weight material and permit redirection of exhaust gases from turbojet engines of tilt rotor aircraft as nacelles of the aircraft transition between vertical and horizontal flight. Use of a controller permits coordination between exhaust redirection and nacelle position.

The invention relates to turbo molecular pumps enabling high pumping speed. The disclosure suggests using one or more cage-like rotor stages to optimize pumping speed on vacuum systems with low gas flows and low ultimate pressures. This allows for a smaller motor as well as smaller overall form factor and makes it well suited, in particular, for compact mass spectrometers and desk-top mass spectrometers.

The use of magnesium oxide, reactive alumina and aluminium oxide as a base provides for a new erosion-resistant material upon sintering.

A radial compressor impeller, having a hub-like main body, whose flow-guiding surface has a contour that increases in size in the radial direction from a flow inlet end in the direction of a flow outlet end, moving blades arranged on the hub-like main body, namely first moving blades and second moving blades. The first moving blades are formed longer than the second moving blades. Between each two adjacent first moving blades a second moving blade each is arranged. Third moving blades, which are formed shorter than the second moving blades are arranged between each adjacent first and second moving blade.

The use of magnesium oxide, reactive alumina and aluminium oxide as a base provides for a new erosion-resistant material upon sintering.

An air foil includes a body and a filler. The body may include a chamber formed therein and includes a first metallic material. The filler may at least partially occupy the chamber of the body and may include a second metallic material. The second metallic material may have a comparatively more negative electrode potential than the first metallic material.

The use of magnesium oxide, reactive alumina and aluminium oxide as a base provides for a new erosion-resistant material upon sintering.

The invention relates to turbo molecular pumps enabling high pumping speed. The disclosure suggests using one or more cage-like rotor stages to optimize pumping speed on vacuum systems with low gas flows and low ultimate pressures. This allows for a smaller motor as well as smaller overall form factor and makes it well suited, in particular, for compact mass spectrometers and desk-top mass spectrometers.