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  • Aircraft Design, Testing and Performance
  • 2010-2014  (9)
  • 2005-2009
  • 1975-1979
  • 1965-1969
  • 1950-1954
  • 1940-1944
  • 2012  (9)
  • 1
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    In-Flight Boundary-Layer Transition of a Large Flat Plate at Supersonic Speeds (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A flight experiment was conducted to investigate the pressure distribution, local-flow conditions, and boundary-layer transition characteristics on a large flat plate in flight at supersonic speeds up to Mach 2.00. The tests used a NASA testbed aircraft with a bottom centerline mounted test fixture. The primary objective of the test was to characterize the local flow field in preparation for future tests of a high Reynolds number natural laminar flow test article. A second objective was to determine the boundary-layer transition characteristics on the flat plate and the effectiveness of using a simplified surface coating. Boundary-layer transition was captured in both analog and digital formats using an onboard infrared imaging system. Surface pressures were measured on the surface of the flat plate. Flow field measurements near the leading edge of the test fixture revealed the local flow characteristics including downwash, sidewash, and local Mach number. Results also indicated that the simplified surface coating did not provide sufficient insulation from the metallic structure, which likely had a substantial effect on boundary-layer transition compared with that of an adiabatic surface. Cold wall conditions were predominant during the acceleration to maximum Mach number, and warm wall conditions were evident during the subsequent deceleration.
    Keywords: Aircraft Design, Testing and Performance
    Type: NASA/TM-2012-216021 , DFRC-E-DAA-TN5282
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Rotary-Wing Relevant Compressor Aero Research and Technology Development Activities at Glenn Research Center (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Technical challenges of compressors for future rotorcraft engines are driven by engine-level and component-level requirements. Cycle analyses are used to highlight the engine-level challenges for 3000, 7500, and 12000 SHP-class engines, which include retention of performance and stability margin at low corrected flows, and matching compressor type, axial-flow or centrifugal, to the low corrected flows and high temperatures in the aft stages. At the component level: power-to-weight and efficiency requirements impel designs with lower inherent aerodynamic stability margin; and, optimum engine overall pressure ratios lead to small blade heights and the associated challenges of scale, particularly increased clearance-to-span ratios. The technical challenges associated with the aerodynamics of low corrected flows and stability management impel the compressor aero research and development efforts reviewed herein. These activities include development of simple models for clearance sensitivities to improve cycle calculations, full-annulus, unsteady Navier-Stokes simulations used to elucidate stall, its inception, and the physics of stall control by discrete tip-injection, development of an actuator-duct-based model for rapid simulation of nonaxisymmetric flow fields (e.g., due inlet circumferential distortion), advanced centrifugal compressor stage development and experimentation, and application of stall control in a T700 engine.
    Keywords: Aircraft Design, Testing and Performance
    Type: NASA/TM-2012-217280 , ARL-TR-4757 , E-18035 , 65th Annual Forum and Technology Display (AHS Forum 65); May 27, 2009 - May 29, 2009; Grapevine, TX; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Dual-Pump CARS Measurements in the University of Virginia's Dual-Mode Scramjet: Configuration "A" (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In this paper we describe efforts to obtain canonical data sets to assist computational modelers in their development of models for the prediction of mixing and combustion in scramjet combustors operating in the ramjet-scramjet transition regime. The CARS technique is employed to acquire temporally and spatially resolved measurements of temperature and species mole-fraction at four planes, one upstream of an H2 fuel injector and three downstream. The technique is described and results are presented for cases with and without chemical reaction. The vibrational energy mode in the heated airstream of the combustor was observed to be frozen at near facility heater conditions and significant nonuniformities in temperature were observed, attributed to nonuniformities of temperature exiting the heater. The measurements downstream of fuel injection show development of mixing and combustion, and are already proving useful to the modelers.
    Keywords: Aircraft Design, Testing and Performance
    Type: AIAA Paper 2012-0114 , NF1676L-13977 , 50th AIAA Aerospace Sciences Meeting and Exhibit; Jan 09, 2012 - Jan 12, 2012; Nashville, TN; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Multi-Objective Optimization of a Turbofan for an Advanced, Single-Aisle Transport (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Considerable interest surrounds the design of the next generation of single-aisle commercial transports in the Boeing 737 and Airbus A320 class. Aircraft designers will depend on advanced, next-generation turbofan engines to power these airplanes. The focus of this study is to apply single- and multi-objective optimization algorithms to the conceptual design of ultrahigh bypass turbofan engines for this class of aircraft, using NASA s Subsonic Fixed Wing Project metrics as multidisciplinary objectives for optimization. The independent design variables investigated include three continuous variables: sea level static thrust, wing reference area, and aerodynamic design point fan pressure ratio, and four discrete variables: overall pressure ratio, fan drive system architecture (i.e., direct- or gear-driven), bypass nozzle architecture (i.e., fixed- or variable geometry), and the high- and low-pressure compressor work split. Ramp weight, fuel burn, noise, and emissions are the parameters treated as dependent objective functions. These optimized solutions provide insight to the ultrahigh bypass engine design process and provide information to NASA program management to help guide its technology development efforts.
    Keywords: Aircraft Design, Testing and Performance
    Type: NASA/TM-2012-217428 , E-18118
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Measuring Global Surface Pressures on a Circulation Control Concept Using Pressure Sensitive Paint (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: This report will present the results obtained from the Pressure Sensitive Paint (PSP) technique on a circulation control concept model. This test was conducted at the National Transonic Facility (NTF) at the NASA Langley Research Center. PSP was collected on the upper wing surface while the facility was operating in cryogenic mode at 227 K (-50 oF). The test envelope for the PSP portion included Mach numbers from 0.7 to 0.8 with angle of attack varying between 0 and 8 degrees and a total pressure of approximately 168 kPa (24.4 psi), resulting in a chord Reynolds number of approximately 15 million. While the PSP results did exhibit high levels of noise in certain conditions (where the oxygen content of the flow was very small), some conditions provided good correlation between the PSP and pressure taps, showing the ability of the PSP technique. This work also served as a risk reduction opportunity for future testing in cryogenic conditions at the NTF.
    Keywords: Aircraft Design, Testing and Performance
    Type: NASA/TM-2012-217583 , L-20153 , NF1676L-14846
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Aircraft Configured for Flight in an Atmosphere Having Low Density (2012)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: An aircraft is configured for flight in an atmosphere having a low density. The aircraft includes a fuselage, a pair of wings, and a rear stabilizer. The pair of wings extends from the fuselage in opposition to one another. The rear stabilizer extends from the fuselage in spaced relationship to the pair of wings. The fuselage, the wings, and the rear stabilizer each present an upper surface opposing a lower surface. The upper and lower surfaces have X, Y, and Z coordinates that are configured for flight in an atmosphere having low density.
    Keywords: Aircraft Design, Testing and Performance
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Converting a C-130 Hercules into a Compound Helicopter: A Conceptual Design Study (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Currently, the US Military and NASA are investigating the feasibility of a Vertical/Short Take Off and Landing (VSTOL) aircraft that can provide invaluable aid in the combat theater and significantly improve the civil transportation system. The nominal military mission requirement calls for a 28-ton payload heavy lift capability while the civilian requirements calls for a 90-passenger, 1000-nm range, airliner, as noted in Reference 1. To aid in these aircraft requirements, the present study examined the conversion of a Lockheed Martin C-130 Hercules into a compound aircraft, which would demonstrate the technology required by a much larger version. The present study examined various configurations and rotor blade designs in order to fulfill the nominal mission described previously. It was shown that the initial design of a 180 ft diameter rotor to lift 155,000 lb was not feasible due to material constraints. A revised design, in which the rotor radius was reduced to 55 ft, met the given constraints but required too much power. The decision was made to move to a twin rotor compound to take advantage of the increased disc area and drop the need for anti torque devices. Following this design shift, a new design point was found where all five constraints were met and the power requirements were deemed reasonable. This twin-rotor design was used in NDARC to provide a complete sizing analysis of the chosen design point.
    Keywords: Aircraft Design, Testing and Performance
    Type: ARC-E-DAA-TN728 , AHS Specialists'' Conference on Aeromechanics; Jan 20, 2012 - Jan 22, 2012; San Francisco, CA; United States
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
  • 8
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    In-Flight Boundary-Layer Transition on a Large Flat Plate at Supersonic Speeds (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A flight experiment was conducted to investigate the pressure distribution, local flow conditions, and boundary-layer transition characteristics on a large flat plate in flight at supersonic speeds up to Mach 2.0. The primary objective of the test was to characterize the local flow field in preparation for future tests of a high Reynolds number natural laminar flow test article. The tests used a F-15B testbed aircraft with a bottom centerline mounted test fixture. A second objective was to determine the boundary-layer transition characteristics on the flat plate and the effectiveness of using a simplified surface coating for future laminar flow flight tests employing infrared thermography. Boundary-layer transition was captured using an onboard infrared imaging system. The infrared imagery was captured in both analog and digital formats. Surface pressures were measured with electronically scanned pressure modules connected to 60 surface-mounted pressure orifices. The local flow field was measured with five 5-hole conical probes mounted near the leading edge of the test fixture. Flow field measurements revealed the local flow characteristics including downwash, sidewash, and local Mach number. Results also indicated that the simplified surface coating did not provide sufficient insulation from the metallic structure, which likely had a substantial effect on boundary-layer transition compared with that of an adiabatic surface. Cold wall conditions were predominant during the acceleration to maximum Mach number, and warm wall conditions were evident during the subsequent deceleration. The infrared imaging system was able to capture shock wave impingement on the surface of the flat plate in addition to indicating laminar-to-turbulent boundary-layer transition.
    Keywords: Aircraft Design, Testing and Performance
    Type: DFRC-E-DAA-TN5280 , DFRC-E-DAA-TN5281 , 15th International Symposium on Flow Visualization; Jun 25, 2012 - Jun 28, 2012; Minsk; Byelarus
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 9
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    Deployment of a Pressure Sensitive Paint System for Measuring Global Surface Pressures on Rotorcraft Blades in Simulated Forward Flight (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper will present details of a Pressure Sensitive Paint (PSP) system for measuring global surface pressures on the tips of rotorcraft blades in simulated forward flight at the 14- x 22-Foot Subsonic Tunnel at the NASA Langley Research Center. The system was designed to use a pulsed laser as an excitation source and PSP data was collected using the lifetime-based approach. With the higher intensity of the laser, this allowed PSP images to be acquired during a single laser pulse, resulting in the collection of crisp images that can be used to determine blade pressure at a specific instant in time. This is extremely important in rotorcraft applications as the blades experience dramatically different flow fields depending on their position in the rotor disk. Testing of the system was performed using the U.S. Army General Rotor Model System equipped with four identical blades. Two of the blades were instrumented with pressure transducers to allow for comparison of the results obtained from the PSP. Preliminary results show that the PSP agrees both qualitatively and quantitatively with both the expected results as well as with the pressure taps. Several areas of improvement have been indentified and are currently being developed.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-13791 , 28th Aerodynamic Measurement Technology, Ground Testing, and Flight Testing Conference; Jun 25, 2012 - Jun 28, 2012; New Orleans, LA; United States
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
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