Abstract: Disclosed aircraft and turbofan engines have an active configuration (corresponding to flight, etc.) and an idle configuration (corresponding to ground idle). Turbofan engines comprise a core engine, a nacelle, a bypass duct therebetween, and a bypass splitter shell that extends at least partially between the nacelle and the core engine to define peripheral and interstitial bypass ducts. Bypass flow in the bypass duct splits into peripheral bypass flow and interstitial bypass flow. The relatively cool, slow interstitial bypass flow is directed into relatively hot, fast core exhaust flow from the core engine and into a mixed exhaust duct at least partially defined by the bypass splitter shell. The bypass splitter shell may be selectively positioned to increase (in the idle configuration) or to decrease (in the active configuration) the relative flow of the interstitial bypass flow, thereby cooling and/or slowing the mixed exhaust flow in the idle configuration.

Abstract: A propulsion system and methods are presented. A substantially tubular structure comprises a central axis through a longitudinal geometric center, and a first fan rotates around the central axis, and comprises a first fan hub and first fan blades. The fan hub is rotationally coupled to the substantially tubular structure, and the first fan blades are coupled to the first fan hub and increase in chord length with increasing distance from the first fan hub. A second fan is rotationally coupled to the substantially tubular structure and rotates around the central axis and contra-rotates relative to the first fan. Second fan blades are coupled to the second fan hub, and a nacelle circumscribing the first fan and the second fan is coupled to and rotates with the first fan.

Abstract: A jet noise suppressor including a nozzle having a front end and an opposed rear end, spokes extending radially inward from the nozzle, the spokes defining vents, and a center-body connected to the spokes and in fluid communication with the vents, the center-body being positioned centrally within the nozzle and including a closed front end and an open rear end, wherein the front end of the nozzle entrains a first ambient airflow passing through the nozzle and exiting the rear end of the nozzle proximate a periphery of the nozzle, and wherein the vents entrain a second ambient airflow passing through the center-body and exiting the rear end of the nozzle proximate a center of the nozzle.

Abstract: Disclosed aircraft and turbofan engines have an active configuration (corresponding to flight, etc.) and an idle configuration (corresponding to ground idle). Turbofan engines comprise a core engine, a nacelle, a bypass duct therebetween, and a bypass splitter shell that extends at least partially between the nacelle and the core engine to define peripheral and interstitial bypass ducts. Bypass flow in the bypass duct splits into peripheral bypass flow and interstitial bypass flow. The relatively cool, slow interstitial bypass flow is directed into relatively hot, fast core exhaust flow from the core engine and into a mixed exhaust duct at least partially defined by the bypass splitter shell. The bypass splitter shell may be selectively positioned to increase (in the idle configuration) or to decrease (in the active configuration) the relative flow of the interstitial bypass flow, thereby cooling and/or slowing the mixed exhaust flow in the idle configuration.

Abstract: A propulsion system and methods are presented. A substantially tubular structure comprises a central axis through a longitudinal geometric center, and a first fan rotates around the central axis, and comprises a first fan hub and first fan blades. The fan hub is rotationally coupled to the substantially tubular structure, and the first fan blades are coupled to the first fan hub and increase in chord length with increasing distance from the first fan hub. A second fan is rotationally coupled to the substantially tubular structure and rotates around the central axis and contra-rotates relative to the first fan. Second fan blades are coupled to the second fan hub, and a nacelle circumscribing the first fan and the second fan is coupled to and rotates with the first fan.

Abstract: A method and apparatus for controlling a propeller of a contra-rotation open fan (CROF) engine of an aircraft. A diameter of the propeller is set to be at a first diameter during at least a portion of a first flight condition of the aircraft. The diameter of the propeller is set to be at a second diameter, different from the first diameter, during at least a portion of a second flight condition of the aircraft.

Abstract: A method of controlling plume exhaust heat and/or noise radiation from a turbofan engine assembly having a short nacelle. A mixer duct shell is supported such that a downstream edge of the short nacelle overlays an upstream portion of the mixer duct shell. A first portion of fan exhaust may be routed through the mixer duct shell between its inner surface and an outer surface of a core engine shroud. A second portion of fan exhaust may be routed over an outer surface of the mixer duct shell. At least one of the inner surface and an outer surface of the mixer duct shell may have an acoustic lining including a honeycomb core structure.

Abstract: An airborne mobile platform that has at least one turbofan engine assembly having a fan driven by a core engine, a short nacelle around the fan and a forward portion of the core engine, and a fan exhaust duct through the nacelle. A mixer duct shell is disposed substantially coaxial with and extending forwardly into the fan exhaust duct to provide a mixer duct between the mixer duct shell and a core engine shroud of the core engine. At least a portion of the mixer duct shell has a honeycomb core structure having an inner surface and an outer surface, with an acoustic lining on one of the inner or outer surfaces. The acoustic lining attenuates sound emanating from the turbofan engine assembly.

Abstract: An air vehicle propulsion system incorporates an engine core with a power shaft to drive an outer blade row. The power shaft extends through and is supported by a counter rotation transmission unit which drives an inner blade row in counter rotational motion to the outer blade row. The counter rotation transmission unit exchanges power from the engine core with the shaft. An actuator engages the shaft for translation from a first retracted position to a second extended position.

Abstract: An aircraft configuration that may reduce the level of roaring jet exhaust noise, infrared radiation, sonic boom, or combination thereof directed towards the ground from an aircraft in flight. The aircraft's nacelles are mounted to the aircraft higher than the wings, with substantially vertical stabilizers outboard of the outermost engine. Noise shifting means are provided such as, for each nacelle, primary chevrons at the core nozzle, secondary chevrons at the fan nozzle, a partial bypass mixer, a long duct full flow mixer, or a combination thereof to provide a shift in spectrum distribution of jet exhaust noise from lower to higher frequency. Variable geometry chevrons may be used with increased immersion to provide such a shift just during noise-restricted portions of an aircraft flight profile. The aircraft aerodynamic structural surfaces serve as noise shielding barriers that more effectively block or redirect the frequency shifted noise up and away from communities.

Abstract: An electronic book (ebook) lending system for requiring at-library book activation. The lending system includes a central system for managing and hosting ebooks, the central system including a storage device and a processor to control a user interface that enables a user to interact with the central system. The central system also includes an access device for activating ebooks at the library. A user may reserve an ebook through the user interface accessed by a remote user device or a library device. The content of the ebook is inaccessible to the user until the ebook is activated, wherein a user may activate the ebook by providing user identification information to the access device, and after the ebook is activated, the user may access the content of the ebook remotely. The present disclosure further includes an ebook lending system for incentivizing library visits by patrons and a digital content lending system for requiring at-library digital content activation.

Abstract: An arrangement for an aircraft includes a fuselage, a wing, and a propulsor. The wing may have a wing upper surface, a rear spar and a wing trailing edge. The propulsor may include at least one rotor having a rotor diameter and a rotor axis. The propulsor may be mounted such that the rotor is located longitudinally between the rear spar and the wing trailing edge. The propulsor may also be mounted such that a lowest point of the rotor diameter is located vertically above the wing upper surface.

Abstract: An integrated, single piece mixer-center body ventilation apparatus is disclosed for use with a turbofan jet engine. The apparatus may incorporate a circumferential forward body portion adapted to be coupled to an aft end of a core engine turbine case of the jet engine, and a center body tube portion integrally formed with the forward body portion and having an axially opening vent exit. The forward body portion may have a plurality of inner mixer flow paths in communication with scalloped projecting portions. The inner mixer flow paths direct a pressurized core exhaust flow through the mixer device and mix the pressurized core exhaust flow with a portion of a pressurized fan exhaust flow, to thus significantly cool the pressurized core exhaust flow.

Abstract: An arrangement for an aircraft includes a fuselage, a wing, and a propulsor. The wing may have a wing upper surface, a rear spar and a wing trailing edge. The propulsor may include at least one rotor having a rotor diameter and a rotor axis. The propulsor may be mounted such that the rotor is located longitudinally between the rear spar and the wing trailing edge. The propulsor may also be mounted such that a lowest point of the rotor diameter is located vertically above the wing upper surface.

Abstract: An aircraft configuration that may reduce the level of roaring jet exhaust noise, infrared radiation, sonic boom, or combination thereof directed towards the ground from an aircraft in flight. The aircraft's nacelles are mounted to the aircraft higher than the wings, with substantially vertical stabilizers outboard of the outermost engine. Noise shifting means are provided such as, for each nacelle, primary chevrons at the core nozzle, secondary chevrons at the fan nozzle, a partial bypass mixer, a long duct full flow mixer, or a combination thereof to provide a shift in spectrum distribution of jet exhaust noise from lower to higher frequency. Variable geometry chevrons may be used with increased immersion to provide such a shift just during noise-restricted portions of an aircraft flight profile. The aircraft aerodynamic structural surfaces serve as noise shielding barriers that more effectively block or redirect the frequency shifted noise up and away from communities.

Abstract: An aircraft configuration that may reduce the level of noise, infrared radiation, or combination thereof directed towards the ground from an aircraft in flight. An embodiment of an aircraft includes a fuselage, two forward swept wings, at least one engine mounted to the aircraft and higher than the wings, and vertical stabilizers mounted on each wing outboard of the outermost engine. The leading edge of the wing may extend forward of the leading end of the engine, and the trailing edge of the aft deck may extend aft of the trailing end of the engine. The aft deck may include an upwardly rotatable pitch control surface at the trailing edge of the deck. Engine types may vary, including but not limited to turbofans, prop-fans, and turbo-props. Main wings may be mounted above the longitudinal axis of the fuselage, and canards may likewise be mounted above or below the axis.

Abstract: An aircraft configuration that may reduce the level of noise, infrared radiation, sonic boom, or combination thereof directed towards the ground from an aircraft in flight. In accordance with an embodiment of the present invention, an aircraft includes a tubular fuselage, two delta wings, at least one engine mounted to the aircraft and higher than the wings, and vertical stabilizers mounted on each wing outboard of the outermost engine. Each wing may include a wing strake at the leading edge of the wing and extending to the fuselage and an aft deck. The leading edge of the wing may extend forward of the intake of the engine, and the trailing edge of the aft deck may extend aft of the engine exhaust. The aft deck may include an upwardly rotatable pitch control surface at the trailing edge of the deck.

Abstract: An integrated, single piece mixer-center body ventilation apparatus is disclosed for use with a turbofan jet engine. The apparatus may incorporate a circumferential forward body portion adapted to be coupled to an aft end of a core engine turbine case of the jet engine, and a center body tube portion integrally formed with the forward body portion and having an axially opening vent exit. The forward body portion may have a plurality of inner mixer flow paths in communication with scalloped projecting portions. The inner mixer flow paths direct a pressurized core exhaust flow through the mixer device and mix the pressurized core exhaust flow with a portion of a pressurized fan exhaust flow, to thus significantly cool the pressurized core exhaust flow.

Abstract: An airborne mobile platform that has at least one turbofan engine assembly having a fan driven by a core engine, a short nacelle around the fan and a forward portion of the core engine, and a fan exhaust duct through the nacelle. A mixer duct shell is disposed substantially coaxial with and extending forwardly into the fan exhaust duct to provide a mixer duct between the mixer duct shell and a core engine shroud of the core engine. At least a portion of the mixer duct shell has a honeycomb core structure having an inner surface and an outer surface, with an acoustic lining on one of the inner or outer surfaces. The acoustic lining attenuates sound emanating from the turbofan engine assembly.

Abstract: A method and apparatus for controlling a propeller of a contra-rotation open fan (CROF) engine of an aircraft. A diameter of the propeller is set to be at a first diameter during at least a portion of a first flight condition of the aircraft. The diameter of the propeller is set to be at a second diameter, different from the first diameter, during at least a portion of a second flight condition of the aircraft.