SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS
A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 11 - MAY 30, 2006
05 AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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.
20060013266 NASA Ames Research Center, Moffett Field, CA, USA
Towards Robust Designs Via Multiple-Objective Optimization Methods
Man Mohan, Rai; January 2006; 2 pp.; In English; VKI Lecture Series (Von Karman Institute), 6-10 Mar. 2006, Brussels, Belgium; No Copyright; Avail.: CASI: A01, Hardcopy
Fabricating and operating complex systems involves dealing with uncertainty in the relevant variables. In the case of aircraft, flow conditions are subject to change during operation. Efficiency and engine noise may be different from the expected values because of manufacturing tolerances and normal wear and tear. Engine components may have a shorter life than expected because of manufacturing tolerances.
In spite of the important effect of operating- and manufacturing-uncertainty on the performance and expected life of the component or system, traditional aerodynamic shape optimization has focused on obtaining the best design given a set of deterministic flow conditions. Clearly it is important to both maintain near-optimal performance levels at off-design operating conditions, and, ensure that performance does not degrade appreciably when the component shape differs from the optimal shape due to manufacturing tolerances and normal wear and tear.
These requirements naturally lead to the idea of robust optimal design wherein the concept of robustness to various perturbations is built into the design optimization procedure. The basic ideas involved in robust optimal design will be included in this lecture. The imposition of the additional requirement of robustness results in a multiple-objective optimization problem requiring appropriate solution procedures. Typically the costs associated with multiple-objective optimization are substantial. Therefore efficient multiple-objective optimization procedures are crucial to the rapid deployment of the principles of robust design in industry. Hence the companion set of lecture notes (Single- and Multiple-Objective Optimization with Differential Evolution and Neural Networks ) deals with methodology for solving multiple-objective Optimization problems efficiently, reliably and with little user intervention.
Applications of the methodologies presented in the companion lecture to robust design will be included here. The evolutionary method (DE) is first used to solve a relatively difficult problem in extended surface heat transfer wherein optimal fin geometries are obtained for different safe operating base temperatures. The objective of maximizing the safe operating base temperature range is in direct conflict with the objective of maximizing fin heat transfer. This problem is a good example of achieving robustness in the context of changing operating conditions. The evolutionary method is then used to design a turbine airfoil; the two objectives being reduced sensitivity of the pressure distribution to small changes in the airfoil shape and the maximization of the trailing edge wedge angle with the consequent increase in airfoil thickness and strength. This is a relevant example of achieving robustness to manufacturing tolerances and wear and tear in the presence of other objectives. Author
Design Optimization; Fabrication; Complex Systems; Robustness (Mathematics); Heat Transfer; Operating Temperature; Shape Optimization; Airfoil Profiles; Engine Noise
20060013267 NASA Ames Research Center, Moffett Field, CA, USA
| |
| Tools for Aviation/Aerospace |
| IHS sells products and services designed to meet the needs of today's engineers. To learn more, and for a free quote, please complete the form below. |
|
Impact of Airfoils on Aerodynamic Optimization of Heavy Lift Rotorcraft
Acree, CecilW., Jr.; Martin Preston B.; Romander, Ethan A.; [2006]; 11 pp.; In English; American Helicopter Society Vertical Lift Aircraft Design Conference, 18-20 Jan. 2006, San Francisco, CA, USA; Original contains black and white illustrations; Copyright; Avail.: Other Sources
Rotor airfoils were developed for two large tiltrotor designs, the Large Civil Tilt Rotor (LCTR) and the Military Heavy Tilt Rotor (MHTR). The LCTR was the most promising of several rotorcraft concepts produced by the NASA Heavy Lift Rotorcraft Systems Investigation. It was designed to carry 120 passengers for 1200 nm, with performance of 350 knots cruise at 30,000 ft altitude. A parallel design, the MHTR, had a notional mission of 40,000 Ib payload, 500 nm range, and 300 knots cruise at 4000 ft, 95 F. Both aircraft were sized by the RC code developed by the U. S. Army Aeroflightdynamics Directorate (AFDD). The rotors were then optimized using the CAMRAD II comprehensive analysis code. Rotor airfoils were designed for each aircraft, and their effects on performance analyzed by CAMRAD II. Airfoil design criteria are discussed for each rotor. Twist and taper optimization are presented in detail for each rotor, with discussions of performance improvements provided by the new airfoils, compared to current technology airfoils. Effects of stall delay and blade flexibility on performance are also included. Author
Tilt Rotor Aircraft; Flight Characteristics; Helicopter Design; Payloads; Rotors; Design Analysis; Airfoils
20060013309 Hughes Technical Center, Atlantic City International Airport, NJ, USA
Vertical Drop Test of an ATR 42-300 Airplane
Abramowitz, A.; Smith, T. G.; Vu, T.; Zvanya, J. R.; Mar. 2006; 228 pp.; In English Report No.(s): PB2006-109052; No Copyright; Avail.: National Technical Information Service (NTIS)
On July 30, 2003, the Federal Aviation Administration conducted a vertical impact test of a large high-wing airplane. The test was conducted at the William J. Hughes Technical Center, Atlantic City International Airport, New Jersey. The objective of this test was to determine the impact response of the fuselage, fuel system, floor tracks, seats, and anthropomorphic test dummies when subjected to a severe, but survivable, simulated crash impact. An ATR 42-300 (42-passenger regional transport airplane) was dropped from a height of 14 ft (4.3 meters) that resulted in a vertical impact velocity of 30 ft/s (9.1 m/s). The airplane was configured to simulate a typical flight condition, including seats, cargo, simulated occupants, and simulated fuel. The final test weight of the airplane was 33,200 pounds (15,059 kg). NTIS
Commuter Aircraft; Crashes; Drop Tests
20060013310 Hughes Technical Center, Atlantic City International Airport, NJ, USA, Hi-Tec Systems, Egg Harbor, NJ, USA
| |
| Aerospace Engineering Design |
| ESDU packages provide validated design data, methods and software, offering a valuable toolset to aerospace engineers. To learn more, and for a free quote, please complete the form below. |
|
High-Reach Extendable Turrets with Skin-Penetrating Nozzle
Bagot, K.; Subbotin, N.; Nov. 2005; 36 pp.; In English Report No.(s): PB2006-109051; No Copyright; Avail.: National Technical Information Service (NTIS)
New equipment for aircraft rescue firefighting vehicles can help improve firefighting after an aircraft crash. New equipment such as a high-reach extendable turret (HRET) with skin-penetrating nozzle mounted on an airport firefighting vehicle could extinguish fires faster, apply firefighting agent more accurately on fires, and possibly save passengers lives as a result. The evaluation in this report will determine the extinguishment abilities of an HRET with skin-penetrating nozzle on simulated real fire aircraft crashes and during a full-scale fire field test. One objective of this research was to compare the abilities of an airport firefighting vehicle using an HRET to that of another vehicle using traditional airport firefighting methods of extinguishment on several real fire aircraft crash simulations. Another objective was to evaluate and determine if an airport firefighting vehicle using an HRET with skin-penetrating nozzle can control and extinguish an aircraft interior fire and reduce interior temperatures. Two different research efforts were undertaken for the described objectives. One was completed by the Air Force Research Laboratory using its fire test facility, and the second was completed at the San Antonio Airport using a training aircraft. NTIS
Crashes; Fire Fighting
20060013321 Congressional Budget Office, Washington, DC, USA
Alternatives for Long-Range Ground-Attack Systems
Mar. 2006; 82 pp.; In English Report No.(s): PB2006-109325; No Copyright; Avail.: National Technical Information Service (NTIS)
The recent air campaigns in Afghanistan and Iraq highlighted the utility of long-range ground-attack systems. The Air Forces fleet of B-52, B-1, and B-2 heavy bombers helped coalition forces overcome the limited availability of local air bases by operating from more distant bases and provided responsive air support to ground forces by orbiting over the battlefield for long periods of time. Recognizing those contributions, the Department of Defense (DoD) is in the process of developing new concepts for the role of long-range systems in future conflicts and is also beginning to examine new systems that could be used to attack targets anywhere in the world. This Congressional Budget Office (CBO) study--prepared at the request of the Subcommittee on Strategic Forces of the Senate Committee on Armed Services--looks at the capabilities and costs associated with alternative long-range strike systems that DoD might develop and procure to improve its ability to conduct ground-attack operations. The study compares the advantages, disadvantages, and costs of eight alternative systems--five aircraft-based systems and three missile-based systems. NTIS
Alternatives; Military Operations; Warfare
20060013327 Wichita State Univ., Wichita, KS, USA
Teardown Evaluation of Areas of Interest from the T-34A N141SW Aircraft Wreckage
Laubach, M.; Cope, D.; Mar. 2006; 64 pp.; In English Report No.(s): PB2006-109057; No Copyright; Avail.: CASI: A04, Hardcopy
To aid with the assessment of aging acrobatic aircraft, the Federal Aviation Administration (FAA) teamed with the National Institute for Aviation Research of Wichita State University to teardown and inspect areas of interest from the T -34AN141SW accident aircraft. Due to the recent history of fatigue cracking and failure, a destructive evaluation of the T-34A would be useful to the FAA to specifically address the T-34A concerns, and in a general sense, to assess the condition of a high-time acrobatic category aircraft. The following four areas of interest from the N141SW accident aircraft were examined for cracks and corrosion: right wing front carry-through lower spar, horizontal and vertical stabilizer attachment points, right wing rear spar lower cap wing station 66, and right wing rear spar lower bathtub fitting. Cracks found on these areas of the accident aircraft were opened, and the crack faces were analyzed to determine failure mode. Surrounding structure was also inspected microscopically for additional defects. NTIS
Wreckage; Evaluation; Photographs; Destruction; Defects; Failure Modes; Aircraft
20060013435 NASA Langley Research Center, Hampton, VA, USA
Rapid Assessment of Aircraft Structural Topologies for Multidisciplinary Optimization and Weight Estimation
Samareh, Jamshid A.; Sensmeier, mark D.; Stewart, Bret A.; [2006]; 12 pp.; In English; 47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 1-4 May 2006, Newport, RI, USA; Original contains color and black and white illustrations Contract(s)/Grant(s): NNL04AA72G; 23-064-20-10; No Copyright; Avail.: CASI: A03, Hardcopy
Algorithms for rapid generation of moderate-fidelity structural finite element models of air vehicle structures to allow more accurate weight estimation earlier in the vehicle design process have been developed. Application of these algorithms should help to rapidly assess many structural layouts before the start of the preliminary design phase and eliminate weight penalties imposed when actual structure weights exceed those estimated during conceptual design. By defining the structural topology in a fully parametric manner, the structure can be mapped to arbitrary vehicle configurations being considered during conceptual design optimization. Recent enhancements to this approach include the porting of the algorithms to a platform-independent software language Python, and modifications to specifically consider morphing aircraft-type configurations. Two sample cases which illustrate these recent developments are presented. Author
Aircraft Structures; Topology; Multidisciplinary Design Optimization; Structural Weight; Estimating
20060013458 NASA Langley Research Center, Hampton, VA, USA
INITIALASSESSMENT of SURFACE PRESSURE CHARACTERISTICS of TWO ROTARY WING UAV DESIGNS
Jones, Henry E.; Wong, Oliver D.; Watkins, A. Neal; Noonan, Kevin W.; Reis, Deane G.; Malovrh, Brendon D.; Ingram, Joanne L.; January 2006; 45 pp.; In English; AHS International 62nd Annual Forum and Technology Display, 9-11 May 2006, Phoenix, AZ, USA; Original contains color illustrations; Copyright; Avail.: CASI: A03, Hardcopy
This paper presents results of an experimental investigation of two rotary-wing UAV designs. The primary goal of the investigation was to provide a set of interactional aerodynamic data for an emerging class of rotorcraft. The present paper provides an overview of the test and an introduction to the test articles, and instrumentation. Sample data in the form of fixed system pressure coefficient response to changes in configuration attitude and flight condition for both rotor off and on conditions are presented. The presence of the rotor is seen to greatly affect the magnitude of the response. Pressure coefficients were measured using both conventional pressure taps and via pressure sensitive paint. Comparisons between the two methods are presented and demonstrate that the pressure sensitive paint is a promising method; however, further work on the technique is required. Author
Rotary Wing Aircraft; Pilotless Aircraft; Pressure; Aircraft Design; Subsonic Wind Tunnels; Wind Tunnel Tests
20060013485 NASA Langley Research Center, Hampton, VA, USA
Aircraft Conceptual Design and Risk Analysis Using Physics-Based Noise Prediction
Olson, Erik D.; Mavris, Dimitri N.; [2006]; 22 pp.; In English; 12th AIAA/CEAS Aeroacoustics Conference, 8-10 May 2006, Cambridge, MA, USA; Original contains color and black and white illustrations Contract(s)/Grant(s): 23-065-20-30 Report No.(s): AIAA Paper 2006-2619; Copyright; Avail.: CASI: A03, Hardcopy
An approach was developed which allows for design studies of commercial aircraft using physics-based noise analysis methods while retaining the ability to perform the rapid trade-off and risk analysis studies needed at the conceptual design stage. A prototype integrated analysis process was created for computing the total aircraft EPNL at the Federal Aviation Regulations Part 36 certification measurement locations using physics-based methods for fan rotor-stator interaction tones and jet mixing noise. The methodology was then used in combination with design of experiments to create response surface equations (RSEs) for the engine and aircraft performance metrics, geometric constraints and take-off and landing noise levels. In addition, Monte Carlo analysis was used to assess the expected variability of the metrics under the influence of uncertainty, and to determine how the variability is affected by the choice of engine cycle. Finally, the RSEs were used to conduct a series of proof-of-concept conceptual-level design studies demonstrating the utility of the approach. The study found that a key advantage to using physics-based analysis during conceptual design lies in the ability to assess the benefits of new technologies as a function of the design to which they are applied. The greatest difficulty in implementing physics-based analysis proved to be the generation of design geometry at a sufficient level of detail for high-fidelity analysis. Author
Commercial Aircraft; Design Analysis; Effective Perceived Noise Levels; Aerodynamic Noise; Tradeoffs; Risk; Jet Mixing Flow; Interactional Aerodynamics; Aeroacoustics
Source: NASA
|
IHS sells products and services designed to meet the needs of today's aviation & aerospace engineers, including:
- Quick access to FAA, JAA, ICAO and UK-CAA information and regulations.
- Validated engineering methods, data, principles, worked examples, programs and related equations on over 1340 specific aerospace, process, structural and mechanical engineering topics.
- The IHS Fasteners eCatalog, providing decision support for the identification, specification and sourcing of aerospace & defense standard fasteners/hardware such as bolts, screws, nuts, washers, rivets, studs, etc.
- Standards documents and collections from the top aerospace & aviation standards development organizations, including SAE International, AIAA, AIA, FAA and NASA.
|