Browse Topic: Hypersonic and supersonic aircraft
The flow structure and unsteadiness of shock wave–boundary layer interaction (SWBLI) has been studied using rainbow schlieren deflectometry (RSD), ensemble averaging, fast Fourier transform (FFT), and snapshot proper orthogonal decomposition (POD) techniques. Shockwaves were generated in a test section by subjecting a Mach = 3.1 free-stream flow to a 12° isosceles triangular prism. The RSD pictures captured with a high-speed camera at 5000 frames/s rate were used to determine the transverse ray deflections at each pixel of the pictures. The interaction region structure is described statistically with the ensemble average and root mean square deflections. The FFT technique was used to determine the frequency content of the flow field. Results indicate that dominant frequencies were in the range of 400 Hz–900 Hz. The Strouhal numbers calculated using the RSD data were in the range of 0.025–0.07. The snapshot POD technique was employed to analyze flow structures and their associated
Hypersonic platforms provide a challenge for flight test campaigns due to the application's flight profiles and environments. The hypersonic environment is generally classified as any speed above Mach 5, although there are finer distinctions, such as “high hypersonic” (between Mach 10 to 25) and “reentry” (above Mach 25). Hypersonic speeds are accompanied, in general, by a small shock standoff distance. As the Mach number increases, the entropy layer of the air around the platform changes rapidly, and there are accompanying vortical flows. Also, a significant amount of aerodynamic heating causes the air around the platform to disassociate and ionize. From a flight test perspective, this matters because the plasma and the ionization interfere with the radio frequency (RF) channels. This interference reduces the telemetry links' reliability and backup techniques must be employed to guarantee the reception of acquired data. Additionally, the flight test instrumentation (FTI) package needs
Hypersonic propulsion would allow for air travel at speeds of Mach 6 to 17, or more than 4,600 to 13,000 miles per hour, and has applications in commercial and space travel.
Hypersonic flight vehicles have potential applications in strategic defence, space missions, and future civilian high-speed transportation systems. However, structural integration has significant challenges due to extreme aero-thermo-mechanical coupled effects. Scramjet-powered air-breathing hypersonic vehicles experience extreme heat loads induced by combustion, shock waves and viscous heat dissipation. An active cooling thermal protection system for scramjet applications has the highest potential for thermal load management, especially for long-duration flights, considering the weight penalty associated with the heavier passive thermal insulation structures. We consider the case of active cooling of scramjet engine structural walls with endothermic hydrocarbon fuel. We have developed a semi-analytical quasi-2D heat transfer model considering a prismatic core single cooling channel segment as a representative volume element (RVE) to analyse larger-scale problems. The model includes
Boom Supersonic, the company building supersonic planes, is developing Symphony, a new propulsion system designed and optimized for its Overture supersonic airliner. Boom will be teaming with three industry leaders to develop Symphony including Florida Turbine Technologies (FTT) for engine design, GE Additive for additive technology design consulting, and StandardAero for maintenance.
The flow fields around a flight vehicle at hypersonic speeds are markedly different from those at both subsonic and supersonic speeds. The hypersonic regime is not at a discrete speed but evolves over a continuum as speed increases, but is generally defined as a speed of Mach 5 or higher. The flow fields around a vehicle cause the resultant high temperatures and high heat fluxes for the flight system/materials during hypersonic flight, and these stressors in hypersonic flight are called “The Heat Barrier.” Real gas effects come into play at hypersonic speeds due to these high temperatures, and include vibrational excitation, dissociation, chemical reactions, and ionization. The underlying cause of this change in the flow fields is that the pressure waves created by the body moving through the atmosphere can only travel at the speed of sound. It is these pressure waves that travel ahead of the body and shape the flow field far from the body of a subsonic vehicle. At hypersonic speeds
At hypersonic speed, severe aerodynamic heating is observed, and temperatures are too high to cool by radiation cooling; active cooling such as ablative cooling is helpful in this situation. The Thermal Protection System (TPS) consists of a layer of an ablative material, followed by an insulating material to lower the temperature at the inside wall of the lifting body. The surface area (considering the inside volume of the vehicle constant) of the TPS plays a vital role in heat transfer to the vehicle and heat transferred through the vehicle body. The minimum area sweepback angle (ΛArea-min) is the function of the principal radius (R) and the ratio of the principal radii of the forward bi-curvature stagnation surface (R/r). The ΛArea-min = 80° is obtained for R = 2 m and R/r = 2. The aerothermal analysis of the lifting body is of fundamental interest while designing the TPS. A Computational Fluid Dynamics (CFD) simulation of a two-dimensional (2D) lifting body against thermally perfect
Ultra-efficient catalysts were developed that are cost-effective to make and simple to scale. The 3D-printed catalysts could potentially be used to in future to power hypersonic flight while simultaneously cooling the system.
This document includes recommendations of installations of adequate landing and taxiing lighting systems in aircraft of the following categories: a Single engine personal and/or liaison type b Light twin engine c Large multiengine propeller d Large multiengine turbojet e Military high performance fighter and attack f Helicopter which are subject to the following CFR Parts certification: Part 23 – Airworthiness Standards: Normal, Utility, Acrobatic and Commuter Aircrafts Part 25 – Airworthiness Standards: Transport Category Aircrafts Part 27 – Airworthiness Standards: Normal Category Rotorcraft Part 29 – Airworthiness Standards: Transport Category Rotorcraft
In recent years, NASA, along with partners Boeing and Area-I Inc., have developed the spanwise adaptive wing (SAW). SAWs leverage a thermally triggered actuator made from a NASA-developed shape memory alloy (SMA) to allow outer portions of aircraft wings and control surfaces to be folded to achieve optimal angles during flight. For supersonic aircraft, SAWs can reduce drag and increase performance during the transition from subsonic to supersonic speeds. For subsonic aircraft, SAWs offer increased control and reduced dependency on the tail rudder and associated hydraulic systems, a particularly heavy part of the aircraft.
Hypersonic weapons, unlike ballistic missiles, take unpredictable paths and can evade missile defense systems. To counter hypersonic technologies, radar engineers must build systems that have no holes in coverage and can track such high-speed vehicles. The obstacles radar developers face require collaboration across the board and strategic methods of adapting to evolving advancements.
With hypersonics vital to national security, LIFT, the Detroit-based Department of Defense manufacturing innovation institute, along with the Department of Defense (DoD), recently awarded ATC Materials, Inc. one of the institute’s nationwide Hypersonics Challenge projects. The challenge goal: To demonstrate the repeatable and reliable production of their RIPS molded radio frequency (RF) material. Operating at speeds of Mach 5 or higher, hypersonic and counter-hypersonic vehicles are among the Department of Defense’s top priorities, as well as the development of a safe and secure domestic supply base.
Researchers developed a propulsion system that could pave the way for hypersonic flight, such as travel from New York to Los Angeles in less than 30 minutes. They developed a way to stabilize the detonation needed for hypersonic propulsion by creating a special hypersonic reaction chamber for jet engines.
This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.
Aerospace innovators from government, commercial, and university arenas are developing technologies that would make supersonic flight over land possible, dramatically reducing travel time anywhere in the world. With these advances, engineers also are working to make aircraft more environmentally friendly, eliminating toxic emissions and reducing the amount of energy required for flight.
This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.
“An Assessment of Planar Waves” provides background on some of the history of planar waves, which are time-dependent variations of inlet recovery, as well as establishing a hierarchy for categorizing various types of planar waves. It further identifies approaches for establishing compression-component and engine sensitivities to planar waves, and methods for accounting for the destabilizing effects of planar waves. This document contains an extensive list and categorization (see Appendix A) of references to aid both the newcomer and the practitioner on this subject. The committee acknowledges that this document addresses only the impact of planar waves on compression-component stability and does not address the impact of planar waves on augmenter rumble, engine structural issues, and/or pilot discomfort.
The primary challenge with supersonic flight remains the mitigation of the sonic boom to levels that will be acceptable to humans on the ground. As industry progresses towards realizing a commercial supersonic aircraft, the push from regulators to reduce noise levels has intensified. Innovators at NASA Langley Research Center have developed a system for predicting sonic boom propagation of supersonic aircraft. The sBOOMTraj tool enables efficient computation and mitigation of sonic boom loudness across the entire duration of a flight mission.
This document includes requirements of installations of adequate landing and taxiing lighting systems in aircraft of the following categories: a Single engine personal and/or liaison type b Light twin engine c Large multiengine propeller d Large multiengine turbojet/turbofan e Military high-performance fighter and attack f Helicopter This document will cover general requirements and recommended practices for all types of landing and taxi lights. More specific recommendations for LED lights in particular can be found in ARP6402.
This report covers engine tests performed in Altitude Test Facilities (ATFs) with the primary purpose of determining steady state thrust at simulated altitude flight conditions as part of the in-flight thrust determination process. As such it is complementary to AIR1703 and AIR5450, published by the SAE E-33 Technical Committee. The gross thrust determined using such tests may be used to generate other thrust-related parameters that are frequently applied in the assessment of propulsion system performance. For example: net thrust, specific thrust, and exhaust nozzle coefficients. The report provides a general description of ATFs including all the major features. These are: Test cell air supply system. This controls the inlet pressure and includes flow straightening, humidity and temperature conditioning. Air inlet duct and slip joint. Note that the report only covers the case where the inlet duct is connected to the engine, not free jet testing. Thrust stand force measurement system
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