Abstract: An aircraft is provided with an aircraft base pressure drag reduction apparatus including apparatus for ducting boundary layer air on board an aircraft wherein the air produces ram air drag, apparatus for using the air for work, and apparatus for ducting the used boundary layer air to a low pressure area of an aircraft which otherwise produces base pressure drag on the aircraft to reduce the base pressure drag that the low pressure area would otherwise produce. In a more particular embodiment of the invention the low pressure area of the aircraft is in a fan duct of an aircraft gas turbine engine. In the preferred embodiment the low pressure area in a fan duct of an aircraft gas turbine engine is on the pylon fairing and the means for using the air for work includes at least one means for bleeding boundary layer air from the surface of the aircraft for reducing aircraft boundary layer induced drag.

Abstract: An environmental control system for supplying aircraft or cabin air to an aircraft is provided with a propulsive engine compressor bleed supply means and an ECS bleed air flow control means which includes an energy recovery means for using the unrequired or unused energy to pump boundary layer air from the surface of the aircraft, such as from the engine nacelle, and exhaust this air rearward of the engine to produce thrust, thus returning some of this unused energy to the propulsive engine.

Abstract: An aircraft gas turbine engine is provided with a starting air turbine that is directly connected through the starter gearbox to the high pressure (HP) shaft and is provided with an apparatus to extract excess energy from engine compressor bleed air, return it to the engine, and to start the engine with compressed air from starting air sources, and to cool and provide compressed air for powering the Environmental Control System (ECS) and using the bleed air for cabin refreshening. The air turbine may be connected to a nacelle boundary layer bleed compressor to bleed boundary layer air from a forward portion of the nacelle to reduce nacelle surface drag. The ECS may be provided with a wing boundary layer bleed means which uses a cooling air fan in the ECS to draw cooling air through the heat exchangers in the ECS pack from the boundary layer air from a forward portion of the aircraft's wing to reduce its surface drag.

Abstract: An aircraft gas turbine engine is provided with an electrically powered boundary layer air bleed apparatus for bleeding boundary layer air off the nacelle and the wing or another part of the aircraft outer skin in order to reduce boundary layer or surface drag and using the boundary layer air as a source of compressed air and cooling air for the aircraft's environmental control system (ECS).

Abstract: A heat exchange system for a supersonic flight vehicle. A first conduit connects the gas (e.g., helium) exit of a compressor of a gas-driven turbocompressor to the gas inlet of a turbine of the turbocompressor, and a second conduit connects the gas outlet to the turbine to the gas entrance of the compressor. The first conduit has a portion positioned near a hotter temperature region (e.g., the combustor wall) and the second conduit has a portion positioned near a colder temperature region (e.g., the fuel region) of the flight vehicle. The temperature difference self powers the turbocompressor which can transfer large amounts of heat and which is hermetically-sealed in a housing against gas leaks.

Abstract: A method of operating a scramjet engine having an improved low pressure combustion cycle is disclosed. Apparatus for carrying out the method is also disclosed. The method includes the steps of providing supersonic compressed airflow to a combustor and supplying fuel to the combustor for generating a fuel/air mixture having a predetermined temperature less than a temperature required for spontaneous ignition of the fuel/air mixture. The method also includes igniting the fuel/air mixture for sustaining recombination reactions of the fuel/air mixture for generating combustion gases. In the preferred embodiment, the fuel/air mixture is ignited by generating a boundary layer of airflow having atomic oxygen and channeling the boundary layer into the combustor for mixing with a portion of the fuel for generating a boundary layer fuel/oxygen mixture subject to spontaneous ignition.

Abstract: A propulsion system and method having means for cooling the combustor liner and throat liner of a rocket casing by endothermic pyrolysis of a hydrocarbon fuel in the fuel passageway which is adjacent to and surrounding the combustor liner and the throat liner. Means is provided for high heat flux to the combustor liner and throat liner from combustion within the rocket casing whereby the temperature of the liners exceeds their thermal limits. Catalyst means are utilized for the endothermic pyrolysis. Hydrocarbon fuel is passed through the fuel passageway; heat is provided from the combustion of fuel in the combustion chamber to the fuel passageway by radiation through the combustor liner and the throat liner; and the hydrocarbon fuel is heated at a temperature sufficient to cause the endothermic pyrolysis of the hydrocarbon in the fuel passageway.

Abstract: A woven, silicon carbide fiber inner wall forms a combustor liner and a nozzle throat liner, and a woven silicon carbide fiber outer wall is spaced from the inner wall to form a fuel passageway. The silicon carbide fibers are woven to conduct heat from the combustor and nozzle throat to the fuel passageway and thereby provide heat for the endothermic pyrolysis of the fuel in a propulsion system having a rocket casing containing a combustor, propellant injectors, nozzle throat and nozzle. The fuel passageway is adjacent to and surrounds the combustor and nozzle throat, and fuel is endothermically pyrolyzed in the fuel passageway.

Abstract: In a propulsion system which includes a rocket casing having a combustor chamber with a combustor liner and a nozzle throat chamber with a nozzle throat liner; a fuel passageway adjacent to and surrounding the combustor liner and nozzle throat liner which form the inner wall of the fuel passageway, the outerwall of the fuel passageway being spaced from the innerwall to form the passageway, a plurality of flow directing vances disposed in the fuel passageway to direct the fuel in the fuel passageway circumferentially. In the propulsion system, the fuel travels a longer path through the passageway, and the residence time of fuel in the passageway is increased to promote heat transfer to the fuel in the passageway. A plurality of fuel injection holes in the combustor liner are also arranged so that fuel is injected into the combustion chamber in a direction which promotes circumferential motion of the fuel.

Abstract: An aircraft having a propulsion system which utilizes a dual fuel system having an inner tank for containing a cryogenic fuel and an outer tank surrounding the inner tank for containing a second fuel wherein the second fuel is a fuel having a low freezing point and a high boiling point which acts as an insulator for the cryogenic fuel in the inner tank. Both the inner tank and the outer tank are non-vacuum type tanks, and by surrounding the inner tank containing for example, liquid hydrogen, with pre-cooled liquid and/or gaseous hydrocarbon in the outer tank, excessive boil-off of the liquid hydrogen is prevented at high altitudes. By using this propulsion system and method, the outer wall of the outer tank is the skin of the aircraft, and the shape of the outer wall of the outer tank conforms to the aerodynamic shape of the aircraft.

Abstract: A propulsion system which utilizes hydrocarbon and hydrogen fuel, having means for cooling of the combustor liner and throat liner of a rocket casing by endothermic pyrolysis of the hydrocarbon in the presence of hydrogen in the fuel passageway. The hydrogen in the fuel accelerates the rate of endothermic pyrolysis in the fuel passageway which is adjacent to and surrounds the combustor liner and the throat liner. Means is also provided for high heat flux to the combustor liner and throat liner from combustion within the rocket casing so that the temperature of the liners exceeds their thermal limits. By the propulsion system and method, hydrocarbon fuel and hydrogen are passed through the fuel passageway which is adjacent to and surrounds the combustor liner and the throat liner in a rocket casing, and heat from the combustion of fuel and hydrogen in the combustion chamber is provided to the fuel passageway by radiation through the combustor liner and the throat liner.

Abstract: A centrifugal pump is provided for degrading antimisting fuel. The centrifugal pump has a rotary impeller closely surrounded by a vaned diffuser for receiving fuel therefrom. The diffuser includes a plurality of recirculation channels disposed along its inner circumferential surface for directing some of the fuel which passes from the impeller to the diffuser back to the impeller for enhancing the degradation of the fuel. Other embodiments are disclosed.

Abstract: An energy recovery system is provided for an aircraft gas turbine engine of the type in which some of the pneumatic energy developed by the engine is made available to support systems such as an environmental control system. In one such energy recovery system, some of the pneumatic energy made available to but not utilized by the support system is utilized to heat the engine fuel immediately prior to the consumption of the fuel by the engine. Some of the recovered energy may also be utilized to heat the fuel in the fuel tanks. Provision is made for multi-engine applications wherein energy recovered from one engine may be utilized by another one of the engines or systems associated therewith.

Abstract: A centrifugal pump is provided for degrading antimisting fuel. The centrifugal pump has a rotary impeller closely surrounded by a vaned diffuser for receiving fuel therefrom. The diffuser includes a plurality of recirculation channels disposed along its inner circumferential surface for directing some of the fuel which passes from the impeller to the diffuser back to the impeller for enhancing the degradation of the fuel. Other embodiments are disclosed.

Abstract: An energy recovery system is provided for an aircraft gas turbine engine of the type in which some of the pneumatic energy developed by the engine is made available to support systems such as an environmental control system. In one such energy recovery system, some of the pneumatic energy made available to but not utilized by the support system is utilized to heat the engine fuel immediately prior to the consumption of the fuel by the engine. Some of the recovered energy may also be utilized to heat the fuel in the fuel tanks. Provision is made for multi-engine applications wherein energy recovered from one engine may be utilized by another one of the engines or systems associated therewith.

Abstract: A fuel delivery system is presented wherein first and second heat exchanger means are each adapted to provide the transfer of heat between the fuel and a second fluid such as lubricating oil associated with the gas turbine engine. Valve means are included which are operative in a first mode to provide for flow of the second fluid through both first and second heat exchanger means and further operative in a second mode for bypassing the second fluid around the second heat exchanger means.

Abstract: A method is provided for manufacturing a concentric-tube heat exchanger which includes at least a pair of concentric tubes disposed one within the other to form an annular longitudinally extending flow channel in which a plurality of heat transfer promoting fins reside. The method includes the step of applying a radially directed force to one of the pair of concentric tubes in sufficient magnitude to permanently deform the tube into engagement with the plurality of heat transfer promoting fins.

Abstract: A concentric-tube heat exchanger is provided which includes a first longitudinally extending annular flow passage adapted to provide a flow path for a first fluid flowing therein and a first plurality of annular heat transferring plates disposed consecutively in the axial direction in the annular flow passage. The plates extend radially across the annular passage and each have a first set of apertures extending axially through the plate. First means are provided for at least partially defining a second longitudinally extending flow passage for a second fluid. The second flow passage is disposed concentrically with the first annular flow passage and is in sufficient proximity thereto to permit a transfer of heat between the first and second fluids through said first plates in the radial direction.

Abstract: A gas turbine engine fuel delivery and control system is provided with means to recirculate all fuel in excess of fuel control requirements back to the aircraft fuel tank, thereby increasing the fuel pump heat sink and decreasing the pump temperature rise without the addition of valving other than that normally employed. A fuel/oil heat exchanger and associated circuitry is provided to maintain the hot engine oil in heat exchange relationship with the cool engine fuel. Where anti-icing of the fuel filter is required, means are provided to maintain the fuel temperature entering the filter at or above a minimum level to prevent freezing thereof. In one embodiment, a divider valve is provided to take all excess fuel from either upstream or downstream of the fuel filter and route it back to the tanks, the ratio of upstream to downstream extraction being a function of fuel pump discharge pressure.

Abstract: A gas turbine engine fuel delivery and control system is provided with means to recirculate all fuel in excess of fuel control requirements back to the aircraft fuel tank, thereby increasing the fuel pump heat sink and decreasing the pump temperature rise without the addition of valving other than that normally employed. A fuel/oil heat exchanger and associated circuitry is provided to maintain the hot engine oil in heat exchange relationship with the cool engine fuel. Where anti-icing of the fuel filter is required, means are provided to maintain the fuel temperature entering the filter at or above a minimum level to prevent freezing thereof. In one embodiment, a divider valve is provided to take all excess fuel from either upstream or downstream of the fuel filter and route it back to the tanks, the ratio of upstream to downstream extraction being a function of fuel pump discharge pressure.