Studies of airframe propulsion system integration for Mach 6 cruise vehicles
Airframe-propulsion system integration for hypersonic aircraft
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Airframe-propulsion system integration for hypersonic aircraft
An overview of the Aeroelastic Design Optimization Program (ADOP) at the Douglas Aircraft Company is given. A pilot test program involving the animation of mode shapes with solid rendering as well as wire frame displays, a complete aircraft model of a high-altitude hypersonic aircraft to test ADOP procedures, a flap model, and an aero-mesh modeler for doublet lattice aerodynamics are discussed.
In support of NASA’s evaluation of its future research thrusts for its hypersonics program, NASA commissioned independent studies of the market for commercial hypersonic transportation. SAIC and BryceTech (formerly Bryce Space and Technology) were awarded one of these independent studies to assist NASA in better understanding: (1) the passenger demand for high-speed aviation travel; (2) the pressures on the business case for developing and operating a hypersonic aircraft for the commercial aviation market; and (3) the non-technical (i.e., societal) barriers and challenges, including the steps NASA and the Government could take to overcome those barriers and challenges. Our approach to addressing these three tasks for NASA included modeling future demand and future business operations, considering global air transportation at speeds of Mach 2 to Mach 7. The team forecast premium air travel demand through 2060 and assessed the willingness of passengers of different income and wealth levels to pay to save time on flights between 800 city pairs. With the total addressable market defined, we examined industry-level business case viability for several aircraft speed and range cases. Considering operating and manufacturing costs for routes that could be serviced profitably, as well as typical profitability targets for the aviation industry, we quantified the level of RDT&E funding available to support each business case.
In support of NASA’s evaluation of its future research thrusts for its hypersonics program, NASA commissioned independent studies of the market for commercial hypersonic transportation. SAIC and BryceTech (formerly Bryce Space and Technology) were awarded one of these independent studies to assist NASA in better understanding: (1) the passenger demand for high-speed aviation travel; (2) the pressures on the business case for developing and operating a hypersonic aircraft for the commercial aviation market; and (3) the non-technical (i.e., societal) barriers and challenges, including the steps NASA and the Government could take to overcome those barriers and challenges. Our approach to addressing these three tasks for NASA included modeling future demand and future business operations, considering global air transportation at speeds of Mach 2 to Mach 7. The team forecast premium air travel demand through 2060 and assessed the willingness of passengers of different income and wealth levels to pay to save time on flights between 800 city pairs. With the total addressable market defined, we examined industry-level business case viability for several aircraft speed and range cases. Considering operating and manufacturing costs for routes that could be serviced profitably, as well as typical profitability targets for the aviation industry, we quantified the level of RDT&E funding available to support each business case.
Optimum body length and volume design for minimal drag characteristics of hypersonic aircraft
Boundary-layer shape measurements at the engine inlet on four different hypersonic aircraft forebody designs (with no engine on the forebody) are reported. The measurements provide a qualitative assessment of the effectiveness of various forebody geometries as engine inlet precompression surfaces. The designs, tested in a hypersonic tunnel at Mach 6 and a nominal freestream Reynolds number of 30,500,000, included a semiconical forebody, a configuration similar to a slab delta wing, a conical nose blended into a flat surface, and a conical, complex forebody shape. Boundary layer height as a function of forebody compression is shown for each design.
Hypersonic aerodynamic characteristics of aircraft configurations with canard controls
A 1/10-scale model of a proposed hypersonic aircraft with an integrated scramjet was tested. The investigation took place over a Mach number range from 0.2 to 0.7 and an angle of attack range from 2 deg to approximately 17 deg at a sideslip angle of 0 deg. The primary configuration variables studied were engine location, internal engine geometry, and external engine geometry. The results are presented without analysis.
This thesis researches potential failure conditions within supersonic and potential hypersonic aircraft. The most critical off-nominal situations have been identified to be Engine Failures, Rapid Decompression and High Altitude Radiation. Having in mind, current regulatory requirements as well as past operations of Concorde, potential locations for different speeds have been modeled to identify safe operational volumes. With an emphasis on the engine failure case as part of the thesis requirement, a potential first order approach to future DAA systems is described in order to add these models on top of current conflict resolution models.
Advanced aircraft engine research within NASA Lewis is being focused on propulsion systems for subsonic, supersonic, and hypersonic aircraft. Each of these flight regimes requires different types of engines, but all require advanced materials to meet their goals of performance, thrust-to-weight ratio, and fuel efficiency. The high strength/weight and stiffness/weight properties of resin, metal, and ceramic matrix composites will play an increasingly key role in meeting these performance requirements. At NASA Lewis, research is ongoing to apply graphite/polyimide composites to engine components and to develop polymer matrices with higher operating temperature capabilities. Metal matrix composites, using magnesium, aluminum, titanium, and superalloy matrices, are being developed for application to static and rotating engine components, as well as for space applications, over a broad temperature range. Ceramic matrix composites are also being examined to increase the toughness and reliability of ceramics for application to high-temperature engine structures and components.
Advanced aircraft engine research within NASA Lewis is being focused on propulsion systems for subsonic, supersonic, and hypersonic aircraft. Each of these flight regimes requires different types of engines, but all require advanced materials to meet their goals of performance, thrust-to-weight ratio, and fuel efficiency. The high strength/weight and stiffness/weight properties of resin, metal, and ceramic matrix composites will play an increasingly key role in meeting these performance requirements. At NASA Lewis, research is ongoing to apply graphite/polyimide composites to engine components and to develop polymer matrices with higher operating temperature capabilities. Metal matrix composites, using magnesium, aluminum, titanium, and superalloy matrices, are being developed for application to static and rotating engine components, as well as for space applications, over a broad temperature range. Ceramic matrix composites are also being examined to increase the toughness and reliability of ceramics for application to high-temperature engine structures and components.
Many types of hypersonic aircraft configurations are currently being studied for feasibility of future development. Since the control of the hypersonic configurations throughout the speed range has a major impact on acceptable designs, it must be considered in the conceptual design stage. The ability of the aerodynamic analysis methods contained in an industry standard conceptual design system, APAS II, to estimate the forces and moments generated through control surface deflections from low subsonic to high hypersonic speeds is considered. Predicted control forces and moments generated by various control effectors are compared with previously published wind tunnel and flight test data for three configurations: the North American X-15, the Space Shuttle Orbiter, and a hypersonic research airplane concept. Qualitative summaries of the results are given for each longitudinal force and moment and each control derivative in the various speed ranges. Results show that all predictions of longitudinal stability and control derivatives are acceptable for use at the conceptual design stage. Results for most lateral/directional control derivatives are acceptable for conceptual design purposes; however, predictions at supersonic Mach numbers for the change in yawing moment due to aileron deflection and the change in rolling moment due to rudder deflection are found to be unacceptable. Including shielding effects in the analysis is shown to have little effect on lift and pitching moment predictions while improving drag predictions.
Many types of hypersonic aircraft configurations are currently being studied for feasibility of future development. Since the control of the hypersonic configurations throughout the speed range has a major impact on acceptable designs, it must be considered in the conceptual design stage. Here, an investigation of the aerodynamic control effectiveness of highly swept delta planforms operating in ground effect is presented. A vortex-lattice computer program incorporating a free wake is developed as a tool to calculate aerodynamic stability and control derivatives. Data generated using this program are compared to experimental data and to data from other vortex-lattice programs. Results show that an elevon deflection produces greater increments in C sub L and C sub M in ground effect than the same deflection produces out of ground effect and that the free wake is indeed necessary for good predictions near the ground.
The detailed properties of sonic booms have to be better understood before commercial, next generation, supersonic and hypersonic aircraft can be properly developed. Experimental tests and measurements are needed to help sort the physical details of the flows at realistic test conditions. Some of these tests can be made in wind tunnels, but the need for full flight conditions simulation, the problem of tunnel wall interference, and the short distance the shocks can be examined from the aircraft, limit the usefulness of wind tunnel tests. Previous measurement techniques for examining the flow field of aircraft in flight have included pressure measurements on the aircraft, ground based pressure measurements, and flow field measurements made with chase aircraft. Obtaining data with chase planes is a slow and difficult process, and is limited in how close it can be obtained to the test aircraft. A need clearly existed for a better technique to examine the shock structure from the plane to large distances from the plane. A new technique has been recently developed to obtain schlieren photographs of aircraft in flight (SAF). Preliminary results have been obtained, and the technique holds promise as a tool to study the shape and approximate strength of the shock wave structure around the test aircraft, and examine shock wave details all the way from the aircraft to near the ground. The current paper describes this approach, and gives some preliminary test results.
The Ohio State University planned to conduct a conceptual design of a single research vehicle that could be used to explore the flight regime from Mach 6 to Mach 12. Since this aircraft will be a special purpose vehicle, it need not take off and land in a conventional manner. Indeed, if this aircraft were launched from a larger aircraft that carried it to altitude, then conventional landing gear would not be needed and the extra weight of the fuel needed to take off and climb into the stratosphere would be eliminated. The focus of the students' project was on the design of a carrier aircraft answering to the specifications. Its mission is to take off with the research aircraft from runways of less than 15,000 feet, climb to 40,000 feet, and release the hypersonic aircraft at the speed of Mach 8, and return to base. The range of this mission is 2000 n.m. This study includes the conception of an optimized aircraft (geometry, weights, propulsion, aerodynamics, interactions between the two aircraft, etc.), the longitudinal stability of the composite, and the separation critical phase.
The effects of fuselage cross sections and structural members on the performance of hypersonic cruise aircraft are evaluated. Representative fuselage/tank area structure was analyzed for strength, stability, fatigue and fracture mechanics. Various thermodynamic and structural tradeoffs were conducted to refine the conceptual designs with the primary objective of minimizing weight and maximizing aircraft range.
Nasa aeronautical research program - helicopters, supersonic transport, stol vehicles, multimission aircraft & x-15 - congressional hearings
Issues and advances in current hypersonic flow research perceived to be of interest in theoretical fluid/gas dynamics are reviewed. Particular attention is given to the hypersonic aircraft as waverider, computational methods and theoretical development in the study of viscous interaction, and boundary-layer instability and transition studies. In the present framework the study of viscous hypersonic flow faces transition problems of two kinds which represent the two major areas of current research: the turbulence transition in the high Re range and the transition to the free-molecule limit.