SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS
A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 43, ISSUE 16 - AUGUST 12, 2005
05 AIRCRAFT DESIGN, TESTING AND PERFORMANCE - PART III
Includes all stages of design of aircraft and aircraft structures and systems.
Also includes aircraft testing, performance, and evaluation, and aircraft and flight simulation technology.
For related information see also 18 Spacecraft Design, Testing and Performance; and 39 Structural Mechanics.
For land transportation vehicles see 85 Technology Utilization and Surface Transportation.
20050196633 NASA Langley Research Center, Hampton, VA, USA
Pneumatic Flap Performance for a 2D Circulation Control Airfoil, Steady and Pulsed
Jones, Gregory S.; Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 2; June 2005, pp. 845-888; In English; See also 20050196628; Original contains color and black and white illustrations; No Copyright; Avail: CASI; A03, Hardcopy
Circulation Control technologies have been around for 65 years, and have been successfully demonstrated in laboratories and flight vehicles alike, yet there are few production aircraft flying today that implement these advances. Circulation Control techniques may have been overlooked due to perceived unfavorable trade offs of mass flow, pitching moment, cruise drag, noise, etc. Improvements in certain aspects of Circulation Control technology are the focus of this paper. This report will describe airfoil and blown high lift concepts that also address cruise drag reduction and reductions in mass flow through the use of pulsed pneumatic blowing on a Coanda surface. Pulsed concepts demonstrate significant reductions in mass flow requirements cor Circulation Control, as well as cruise drag concepts that equal or exceed conventional airfoil systems. Author
Circulation Control Airfoils; Coanda Effect; Control Systems Design; Drag Reduction; Pneumatics; Blowing
20050196635 Novatek, Inc., USA
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Design and Fabrication of Circulation Control Test Articles
Burdges, Kenneth P.; Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 2; June 2005, pp. 723-741; In English; See also 20050196628; Original contains color illustrations; No Copyright; Avail: CASI; A03, Hardcopy
This paper is an overview of a decade of experience in Computer Aided Design (CAD) and Computer Aided Machining (CAM) of test articles for wind tunnel and road testing of Circulation Control (CC) vehicles. Internal flow design features, such as sub-plenums and instrumentation are discussed. Techniques for slot adjustment mechanisms are described as well as difficulties in machining thin edges for blowing slots. Test articles include low speed and transonic wind tunnel models, racecar models and wings. Application of CC for drag reduction of heavy trucks and sport utility vehicles is included to illustrate some current design problems. Author
Design Analysis; Fabrication; Computer Aided Design; Wind Tunnel Tests; Drag Reduction
20050196637 NASA Langley Research Center, Hampton, VA, USA
Wake Vortex Wingtip-Turbine Powered Circulation Control High-Lift System
Moore, Mark D.; Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 2; June 2005, pp. 641-674; In English; See also 20050196628; Original contains color and black and white illustrations; No Copyright; Avail: CASI; A03, Hardcopy
NASA s Vehicle Systems Program is investing in aeronautics technology development across six vehicle sectors, in order to improve future air travel. These vehicle sectors include subsonic commercial transports, supersonic vehicles, Uninhabited Aerial Vehicles (UAVs), Extreme Short Takeoff and Landing (ESTOL) vehicles, Rotorcraft, and Personal Air Vehicles (PAVs). While the subsonic transport is firmly established in U.S. markets, the other vehicle sectors have not developed a sufficient technology or regulatory state to permit widespread, practical use. The PAV sector has legacy products in the General Aviation (GA) market, but currently only accounts for negligible revenue miles, sales, or market share of personal travel. In order for PAV s to ever capture a significant market, these small aircraft require technologies that permit them to be less costly, environmentally acceptable, safer, easier to operate, more efficient, and less dependent on large support infrastructures. Author
Vortices; Wakes; Powered Lift Aircraft; Rotary Wing Aircraft; Turbines
20050196638 Complere, Inc., Pacific Grove, CA, USA
Measurement and Analysis of Circulation Control Airfoils
Owen, F. Kevin; Owen, Andrew K.; Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 2; June 2005, pp. 947-955; In English; See also 20050196628; Original contains color illustrations; No Copyright; Avail: CASI; A02, Hardcopy
A wind tunnel investigation has been conducted of a two-dimensional circulation control airfoil section equipped with trailing edge blowing. The tests were conducted in the NASA-Ames 2 x 2-Ft. Variable Density Transonic Wind Tunnel over a range of freestream Mach number and unit Reynolds numbers. Detailed non-intrusive flow-field measurements of the mean flow and turbulent properties were obtained in the airfoil wake for a number of different blowing coefficients. These results have been related to the circulation control airfoil performance obtained from direct surface pressure measurements. The analysis shows that wind tunnel wall interference can have significant influence on high lift test results. This influence must be accounted for before wind tunnel test data can be used for design extrapolation or for turbulence modeling and CFD assessments. Corrections have been made for finite aspect ratio wind tunnel wall interference in order to provide interference free benchmark data for turbulence modeling and CFD code development and validation. A substantial amount of additional data awaits analysis. Author
Circulation Control Airfoils; Wind Tunnel Tests; Trailing Edges; Blowing; Computational Fluid Dynamics; Airfoil Profiles; Aerodynamic Interference
20050196731 NASA Glenn Research Center, Cleveland, OH, USA
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A Probabilistic Assessment of NASA Ultra-Efficient Engine Technologies for a Large Subsonic Transport
Tong, Michael T.; Jones, Scott M.; Arcara, Philip C., Jr.; Haller, William J.; [2004]; 8 pp.; In English; ASME Turbo Expo 2004, 14-17 Jun. 2004, Vienna, Austria Contract(s)/Grant(s): WBS 22-714-09-01 Report No.(s): GT2004-53485; E-14435; No Copyright; Avail: CASI; A02, Hardcopy
NASA’s Ultra Efficient Engine Technology (UEET) program features advanced aeropropulsion technologies that include highly loaded turbomachinery, an advanced low-NOx combustor, high-temperature materials, intelligent propulsion controls, aspirated seal technology, and an advanced computational fluid dynamics (CFD) design tool to help reduce airplane drag. A probabilistic system assessment is performed to evaluate the impact of these technologies on aircraft fuel burn and NOx reductions. A 300-passenger aircraft, with two 396-kN thrust (85,000-pound) engines is chosen for the study. The results show that a large subsonic aircraft equipped with the UEET technologies has a very high probability of meeting the UEET Program goals for fuel-burn (or equivalent CO2) reduction (15% from the baseline) and LTO (landing and takeoff) NOx reductions (70% relative to the 1996 International Civil Aviation Organization rule). These results are used to provide guidance for developing a robust UEET technology portfolio, and to prioritize the most promising technologies required to achieve UEET program goals for the fuel-burn and NOx reductions. Author
Civil Aviation; Computational Fluid Dynamics; Probability Theory; Subsonic Aircraft; NASA Programs; Engine Tests; Technology Assessment
20050196738 Swedish Defence Research Establishment, Linkoeping, Sweden
Business Model Helicopter Unit
Lindell, P. O.; Stjernberger, J.; Pilemalm, S.; Dec. 2004; 88 pp.; In Swedish Report No.(s): PB2005-107460; FOI-R-1419-SE; No Copyright; Avail: CASI; A05, Hardcopy
Changes in the international peace and conflict balance have resulted in new requirements for the technical systems intended to support the command in the Swedish Armed Forces in the future network and task force based defense. Qualities as dynamics and flexibility will be of great importance in the development of technical systems aimed to support command. These systems must be able to support communication between all units in the Swedish Armed Forces and with civil authorities. NTIS
Commerce; Helicopters; Military Operations
20050196810 Toledo Univ., OH, USA, NASA Glenn Research Center, Cleveland, OH, USA
Fan Flutter Analysis Capability Enhanced
Bakhle, Milind A.; Srivastava, Rakesh; Stefko, George L.; Research and Technology 2000; March 2001; 2 pp.; In English; No Copyright; Avail: CASI; A01, Hardcopy
The trend in the design of advanced transonic fans for aircraft engines has been toward the use of complex high-aspect-ratio blade geometries with a larger number of blades and higher loading. In addition, integrally bladed disks or blisks are being considered in fan designs for their potential to reduce manufacturing costs, weight, and complexity by eliminating attachments. With such design trends, there is an increased possibility within the operating region of part-speed stall flutter (self-excited vibrations) that is exacerbated by the reduced structural damping of blisk fans. To verify the aeroelastic soundness of the design, the NASA Glenn Research Center is developing and validating an accurate aeroelastic prediction and analysis capability. Recently, this capability was enhanced significantly as described here. Derived from text
Flutter Analysis; Aeroelastic Research Wings; Aircraft Design; Supersonic Aircraft
20050196822 NASA Langley Research Center, Hampton, VA, USA
Transonic-Small-Disturbance and Linear Analyses for the Active Aeroelastic Wing Program
Wiesman, Carol D.; Silva, Walter A.; Spain, Charles V.; Heeg, Jennifer; [2005]; 20 pp.; In English; 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 18-21 Apr. 2005, Austin, TX, USA Contract(s)/Grant(s): 23-065-50-22; No Copyright; Avail: CASI; A03, Hardcopy
Analysis serves many roles in the Active Aeroelastic Wing (AAW) program. It has been employed to ensure safe testing of both a flight vehicle and wind tunnel model, has formulated models for control law design, has provided comparison data for validation of experimental methods and has addressed several analytical research topics. Aeroelastic analyses using mathematical models of both the flight vehicle and the wind tunnel model configurations have been conducted. Static aeroelastic characterizations of the flight vehicle and wind tunnel model have been produced in the transonic regime and at low supersonic Mach numbers. The flight vehicle has been analyzed using linear aerodynamic theory and transonic small disturbance theory. Analyses of the wind-tunnel model were performed using only linear methods. Research efforts conducted through these analyses include defining regions of the test space where transonic effects play an important role and investigating transonic similarity. A comparison of these aeroelastic analyses for the AAW flight vehicle is presented in this paper. Results from a study of transonic similarity are also presented. Data sets from these analyses include pressure distributions, stability and control derivatives, control surface effectiveness, and vehicle deflections. Author
Aeroelastic Research Wings; Aeroelasticity; Aircraft Structures
20050198858 NASA Glenn Research Center, Cleveland, OH, USA
International Test Program for Synergistic Atomic Oxygen and Vacuum Ultraviolet Radiation Exposure of Spacecraft Materials
Miller, Sharon K.; Research and Technology 2000; March 2001; 2 pp.; In English; No Copyright; Avail: CASI; A01, Hardcopy
The components and materials of spacecraft in low Earth orbit can degrade in thermal and optical performance through interaction with atomic oxygen and vacuum ultraviolet (VUV) radiation, which are predominant in low Earth orbit. Because of the importance of low Earth orbit durability and performance to manufacturers and users, an international test program for assessing the durability of spacecraft materials and components was initiated. Initial tests at the NASA Glenn Research Center consisted of exposure of samples representing a variety of thermal control paints, multilayer insulation materials, and Sun sensors that have been used in space. Materials donated from various international sources were tested alongside materials whose performance is well known, such as Teflon FEP, Kapton H, or Z-93-P white paint. The optical, thermal, or mass loss data generated during the tests were then provided to the participating material suppliers. Data were not published unless the participant donating the material consented to publication. The test program is intended to give spacecraft builders and users a better understanding of degradation processes and effects so that they can improve their predictions of spacecraft performance. Author
Oxygen Atoms; Far Ultraviolet Radiation; Spacecraft Components; Radiation Dosage
20050199061 NASA Langley Research Center, Hampton, VA, USA
Tow-Steered Panels With Holes Subjected to Compression or Shear Loads
Jegley, Dawn C.; Tatting, Brian F.; Guerdal, Zafer; [2005]; 14 pp.; In English; 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 18-21 Apr. 2005, Austin,TX, USA Contract(s)/Grant(s): 23-064-30-34 Report No.(s): AIAA Paper 2005-2081; Copyright; Avail: CASI; A03, Hardcopy
Tailoring composite laminates to vary the fiber orientations within a fiber layer of a laminate to address non-uniform stress states and provide structural advantages such as the alteration of principal load paths has potential application to future low-cost, light-weight structures for commercial transport aircraft. Evaluation of this approach requires the determination of the effectiveness of stiffness tailoring through the use of curvilinear fiber paths in flat panels including the reduction of stress concentrations around the holes and the increase in load carrying capability. Panels were designed through the use of an optimization code using a genetic algorithm and fabricated using a tow-steering approach. Manufacturing limitations, such as the radius of curvature of tows the machine could support, avoidance of wrinkling of fibers and minimization of gaps between fibers were considered in the design process. Variable stiffness tow-steered panels constructed with curvilinear fiber paths were fabricated so that the design methodology could be verified through experimentation. Finite element analysis where each element s stacking sequence was accurately defined is used to verify the behavior predicted based on the design code. Experiments on variable stiffness flat panels with central circular holes were conducted with the panels loaded in axial compression or shear. Tape and tow-steered panels are used to demonstrate the buckling, post-buckling and failure behavior of elastically tailored panels. The experimental results presented establish the buckling performance improvements attainable by elastic tailoring of composite laminates. Author
Laminates; Stress Concentration; Compression Loads; Fiber Orientation; Transport Aircraft; Buckling; Finite Element Method; Stiffness
20050199063 NASA Langley Research Center, Hampton, VA, USA
Persistent Structures in the Turbulent Boundary Layer
Palumbo, Dan; Chabalko, Chris; [2005]; 9 pp.; In English; 11th AIAA/CEAS Aeroacoustics Conference, 23-25 May 2005, Monterey, CA, USA Contract(s)/Grant(s): 23-781-10-13; Copyright; Avail: CASI; A02, Hardcopy
Persistent structures in the turbulent boundary layer are located and analyzed. The data are taken from flight experiments on large commercial aircraft. An interval correlation technique is introduced which is able to locate the structures. The Morlet continuous wavelet is shown to not only locates persistent structures but has the added benefit that the pressure data are decomposed in time and frequency. To better understand how power is apportioned among these structures, a discrete Coiflet wavelet is used to decompose the pressure data into orthogonal frequency bands. Results indicate that some structures persist a great deal longer in the TBL than would be expected. These structure contain significant power and may be a primary source of vibration energy in the airframe. Author
Turbulent Boundary Layer; Commercial Aircraft; Airframes; Wavelet Analysis; Vibration
20050199405 NASA Langley Research Center, Hampton, VA, USA
Utilization of the Building-Block Approach in Structural Mechanics Research
Rouse, Marshall; Jegley, Dawn C.; McGowan, David M.; Bush, Harold G.; Waters,W. Allen; [2005]; 19 pp.; In English; 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 18-21 Apr. 2005, Austin, TX, USA Contract(s)/Grant(s): 23-719-55-TA; Copyright; Avail: CASI; A03, Hardcopy
In the last 20 years NASA has worked in collaboration with industry to develop enabling technologies needed to make aircraft safer and more affordable, extend their lifetime, improve their reliability, better understand their behavior, and reduce their weight. To support these efforts, research programs starting with ideas and culminating in full-scale structural testing were conducted at the NASA Langley Research Center.
Each program contained development efforts that
(a) started with selecting the material system and manufacturing approach;
(b) moved on to experimentation and analysis of small samples to characterize the system and quantify behavior in the presence of defects like damage and imperfections;
(c) progressed on to examining larger structures to examine buckling behavior, combined loadings, and built-up structures; and
(d) finally moved to complicated subcomponents and full-scale components.
Each step along the way was supported by detailed analysis, including tool development, to prove that the behavior of these structures was well-understood and predictable. This approach for developing technology became known as the ‘building-block’ approach. In the Advanced Composites Technology Program and the High Speed Research Program the building-block approach was used to develop a true understanding of the response of the structures involved through experimentation and analysis. The philosophy that if the structural response couldn’t be accurately predicted, it wasn’t really understood, was critical to the progression of these programs. To this end, analytical techniques including closed-form and finite elements were employed and experimentation used to verify assumptions at each step along the way.
This paper presents a discussion of the utilization of the building-block approach described previously in structural mechanics research and development programs at NASA Langley Research Center. Specific examples that illustrate the use of this approach are included from recent research and development programs for both subsonic and supersonic transports. Author
Structural Analysis; Composite Structures; Finite Element Method; Damage; Buckling; Composite Materials
Source: NASA.
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