Induced drag and the efforts to reduce it has been a continuous effort in the past decades. Many wingtip devices have evolved as a result of detailed research. Different winglets have reduced induced in different flight regimes. This paper documents the influence of winglets in the reduction of induced drag in the best possible way. The role of blended, raked wing grid, and spiroid winglets have been documented. It has been noted that different winglets have different efficiencies at different...

Topics: Induced Drag, Blended Winglet, Raked Winglet, Wing Grid & Spiroid Winglets

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188

May 31, 2011
05/11

by
Howsman, Tom; Craft, Mike; ONeil, Danie

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A prototype cooperative multi-robot control architecture suitable for the eventual construction of large space structures has been developed. In nature, there are numerous examples of complex architectures constructed by relatively simple insects, such as termites and wasps, which cooperatively assemble their nests. The prototype control architecture emulates this biological model. Actions of each of the autonomous robotic construction agents are only indirectly coordinated, thus mimicking the...

Topics: AERODYNAMIC DRAG, INDUCED DRAG, FRICTION, WEAR RESISTANCE, RAIL TRANSPORTATION, MAINTENANCE,...

The authors aimed with this work to study the “vortex” on the wing tip of a “Blended Wing Body” aircraft using computational tools available that use the methods of“finite element” and “Computational Fluid Dynamics”. The purpose of it is to reduce the vortex intensity, improving stability, reducing the “induced drag” and promoting less turbulence in the aircraft. This new aircraft configuration is a little different from the ones we have today. Blend Wing Body aircrafts...

Topics: Blended Wing Body, Computational Fluid Dynamics, Finite Element Method, Induced Drag, Vortex.

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224

May 23, 2011
05/11

by
Kautz, Harold E

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A 13 mJ NdYAG 1064 nm, 4 ns, laser pulse was employed to produce ultrasonic plate waves in 20 percent porous SiC/SiC composite tensile specimens of three different architectures. An air coupled 0.5 MHz transducer was used to detect and collect the waveforms which contained first antisymmetric plate wave pulses for determining the shear wave velocity (VS). These results were compared to VS values determined on the same specimens with 0.5 MHz ultrasonic transducers with contact coupling. Averages...

Topics: INDUCED DRAG, NONLINEARITY, WAKES, WING TIPS, INTERACTIONAL AERODYNAMICS, COMPRESSIBILITY,...

Running resistance, the combined resistance induced by aerodynamic drag and mechanical friction, absorbs about 16 percent of railroad budget and maintenance costs. In order to study these losses, AT&SF Railroad entered into a joint research project with the Jet Propulsion Laboratory. Various train configurations were tested when the resulting data was computer analyzed. The Coast-Down Technique was estimated at one percent accuracy. AT&SF is evaluating the data further.

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, INDUCED DRAG, FRICTION, WEAR RESISTANCE,...

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290

Jul 11, 2010
07/10

by
Gladow, D

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The utilization of the rolamite design as: dial indicators, miniature inertial and tape-recorder devices, low pressure transducers, rotary switches, aircraft part instrumentation controls, dimensional gages, and industrial timing and control mechanisms was investigated. Data are also given on rolamite performance as affected by wear, size, acceleration, and band slippage.

Topics: BENDING MOMENTS, INDUCED DRAG, LIFT DRAG RATIO, WING SPAN, AERODYNAMIC LOADS, DRAG REDUCTION, FLOW...

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453

Jul 12, 2010
07/10

by
Brun, R. J.; Gallagher, H. M.; Vogt, D. E

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The trajectories of droplets in the air flowing past NACA 65(1)-208 airfoil and an NACA 65(1)-212 airfoil, both at an angle of attack of 4 degrees, were determined. The amount of water in droplet form impinging on the airfoils, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface affected were calculated from the trajectories and are presented. The amount, extent, and rate of impingement of the NACA 65(1)-208 airfoil are compared with the...

Topics: AERODYNAMIC DRAG, PRANDTL NUMBER, DRAG REDUCTION, INDUCED DRAG, VORTICES, WING PLANFORMS, WINGLETS,...

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Jul 11, 2010
07/10

by
Meyer, G.; Cicolani, L

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An effort to develop techniques for the design of integrated, fully automatic flight control systems for powered lift STOL and VTOL aircraft is described. The structure is discussed of the control system which has been developed to deal with the strong nonlinearities inherent in this class of aircraft, to admit automatic coupling with the advanced ATC requiring accurate execution of complex trajectories, and to admit a variety of active control tasks. The specific case considered is the...

Topics: AIRCRAFT DESIGN, CONTROL EQUIPMENT, CONTROL THEORY, DRAG REDUCTION, FUEL CONSUMPTION, INDUCED DRAG,...

Presentation discussing out-of-the-box thinking about new methods of flight: towards more bird-like flight.

Topics: NASA Technical Reports Server (NTRS), AERODYNAMICS, HANG GLIDERS, AIRCRAFT MODELS, BIRDS, YAW,...

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May 30, 2011
05/11

by
NON

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The Universities Space Research Association received an award of Cooperative Agreement #NCC5-356 on September 29, 1998. The mission of this activity, know as the Cooperative Program in Space Sciences (CPSS), is to conduct space science research and leading-edge instrumentation and technology development, enable research by the space sciences communities, and to expedite the effective dissemination of space science research, technology, data, and information to the educational community and the...

Topics: FLIGHT TESTS, ROLLING MOMENTS, SAFETY, VORTICES, MOMENT DISTRIBUTION, AIRCRAFT WAKES, AERODYNAMIC...

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453

Jul 12, 2010
07/10

by
Herakovich, C. T

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Major areas of study include: (1) edge effects in finite width laminated composites subjected to mechanical, thermal and hygroscopic loading with temperature dependent material properties and the influence of edge effects on the initiation of failure; (2) shear and compression testing of composite materials at room and elevated temperatures; (3) optical techniques for precise measurement of coefficients of thermal expansion of composites; (4) models for the nonlinear behavior of composites...

Topics: AERODYNAMIC DRAG, SURFACES, VORTICES, AIRFOIL PROFILES, AIRFOILS, DRAG REDUCTION, INDUCED DRAG,...

Despite the 80-year history of classical wing theory, considerable research has recently been directed toward planform and wake effects on induced drag. Nonlinear interactions between the trailing wake and the wing offer the possibility of reducing drag. The nonlinear effect of compressibility on induced drag characteristics may also influence wing design. This thesis deals with the prediction of these nonlinear aspects of induced drag and ways to exploit them. A potential benefit of only a few...

Topics: NASA Technical Reports Server (NTRS), INDUCED DRAG, NONLINEARITY, WAKES, WING TIPS, INTERACTIONAL...

Of all the types of drag, induced drag is associated with the creation and generation of lift over wings. Induced drag is directly driven by the span load that the aircraft is flying at. The tools by which to calculate and predict induced drag we use were created by Ludwig Prandtl in 1903. Within a decade after Prandtl created a tool for calculating induced drag, Prandtl and his students had optimized the problem to solve the minimum induced drag for a wing of a given span, formalized and...

Topics: NASA Technical Reports Server (NTRS), INDUCED DRAG, MINIMUM DRAG, WINGS, AIRCRAFT STRUCTURES,...

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828

Jul 23, 2010
07/10

by
Dow, Norris F.; Ramnath, V.; Rosen, B. Walte

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The use of woven fabrics as reinforcements for composites is considered. Methods of analysis of properties are reviewed and extended, with particular attention paid to three-dimensional constructions having through-the-thickness reinforcements. Methodology developed is used parametrically to evaluate the performance potential of a wide variety of reinforcement constructions including hybrids. Comparisons are made of predicted and measured properties of representative composites having biaxial...

Topics: INSTALLING, INDUCED DRAG, MACH NUMBER, REYNOLDS NUMBER, PROPELLERS, SEMISPAN MODELS, TURBOFAN...

The application of the incompressible momentum integral equation to a three-dimensional airfoil was reviewed to interpret the resulting equations in a way that suggests a reasonable experimental technique for determining the spanwise distributions of lift and drag. Consideration was given to constraints that must be placed on the character of the vortex wake structure shed by the wing, to provide the familiar relationship between lift and bound vorticity. It is shown that the induced drag...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, AIRFOILS, FLOW DISTRIBUTION, LIFT, FLOW...

A relatively simple equation is presented for estimating the induced drag ideal efficiency factor e for arbitrary cross sectional wing forms. This equation is based on eight basic but varied wing configurations which have exact solutions. The e function which relates the basic wings is developed statistically and is a continuous function of configuration geometry. The basic wing configurations include boxwings shaped as a rectangle, ellipse, and diamond; the V-wing; end-plate wing; 90 degree...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, EFFICIENCY, INDUCED DRAG, WING PLANFORMS,...

A description of the joint test program objectives and scope is given together with the performance capability of the NASA Langley B-737 instrumented aircraft. The B-737 test run matrix conducted during the first 8 months of this 5-year program is discussed with a description of the different runway conditions evaluated. Some preliminary test results are discussed concerning the Electronic Recording Decelerometer (ERD) readings and a comparison of B-737 aircraft braking performance for...

Topics: NASA Technical Reports Server (NTRS), BOEING 737 AIRCRAFT, AIRCRAFT PERFORMANCE, FRICTION...

The Kasprzyk slotted flap glider airfoil (the Kasper wing) enabling glider flight at 32 km/h and 0.5 m/sec descent speed was wind tunnel tested in the U.S. The test layout is described and reasons offered for discrepancies between wind tunnel results and Polish in flight data: high induced drag caused by relative size of model wing span and tunnel, by vortex attenuators on the model and their proximity to the tunnel wall, nonsimilarity between flow over a smooth wing and flow over the Kasprzyk...

Topics: NASA Technical Reports Server (NTRS), GLIDERS, WIND TUNNEL TESTS, WING PROFILES, FLIGHT TESTS, FLOW...

No abstract available

Topics: NASA Technical Reports Server (NTRS), MINIMUM DRAG, INDUCED DRAG, AIRCRAFT STRUCTURES, LOADS...

Birds do not require the use of vertical tails. They do not appear to have any mechanism by which to control their yaw. As an example the albatross is notable in this regard. The authors believe this is possible because of a unique adaptation by which there exists a triple-optimal solution that provides the maximum aerodynamic efficiency, the minimum structural weight, and it provides for coordination of control in roll and yaw. Until now, this solution has eluded researchers, and remained...

Topics: NASA Technical Reports Server (NTRS), INDUCED DRAG, MINIMUM DRAG, AERODYNAMIC CHARACTERISTICS,...

Aerodynamic characteristics of an aircraft may significantly differ when flying close to the ground rather than when flying up and away. Recent research has also determined that dynamic effects (i.e., sink rate) influence ground effects (GE). A ground effects flight test program of the F-15 aircraft was conducted to support the propulsion controlled aircraft (PCA) program at the NASA Dryden Flight Research Center. Flight data was collected for 24 landings on seven test flights. Dynamic ground...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC COEFFICIENTS, AIRCRAFT LANDING, F-15 AIRCRAFT,...

A linear, inviscid subsonic compressible flow theory is formulated to treat the aerodynamic interaction between the wing and an inviscid upper-surface-blowing (USB) thick jet with Mach number nonuniformity. The predicted results show reasonably good agreement with some available lift and induced-drag data. It was also shown that the thin-jet-flap theory is inadequate for the USB configurations with thick jet. Additional theoretical results show that the lift and induced drag were reduced by...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMICS, JET FLOW, AERODYNAMIC DRAG, COMPRESSIBLE FLOW,...

A method is presented for the in-flight optimization of the lift distribution across the wing for minimum drag of an aircraft in formation flight. The usual elliptical distribution that is optimal for a given wing with a given span is no longer optimal for the trailing wing in a formation due to the asymmetric nature of the encountered flow field. Control surfaces along the trailing edge of the wing can be configured to obtain a non-elliptical profile that is more optimal in terms of minimum...

Topics: NASA Technical Reports Server (NTRS), TRAILING EDGES, FORCE DISTRIBUTION, INDUCED DRAG, AERODYNAMIC...

Of all the types of drag, induced drag is associated with the creation and generation of lift over wings. Induced drag is directly driven by the span load that the aircraft is flying at. The tools by which to calculate and predict induced drag we use were created by Ludwig Prandtl in 1903. Within a decade after Prandtl created a tool for calculating induced drag, Prandtl and his students had optimized the problem to solve the minimum induced drag for a wing of a given span, formalized and...

Topics: NASA Technical Reports Server (NTRS), INDUCED DRAG, MINIMUM DRAG, AIRCRAFT MODELS, WING PROFILES,...

Optimization of L/D through minimizing induced drag through a detailed flow study together with force, pressure and vorticity measurements is considered. Flow visualization with neutral helium bubbles provides an excellent means of observing the effects of configuration changes.

Topics: NASA Technical Reports Server (NTRS), DRAG REDUCTION, STRUCTURAL DESIGN, VORTICES, WING TIPS,...

Lift-dependent induced drag in commercial aviation aircraft is discussed, with emphasis on the necessary compromises between wing and configuration modifications which better lift performance and the weight gains accompanying such modifications. Triangular, rectangular and elliptical configurations for wing ends are considered; attention is also given to airfoil designs incorporating winglets. Water tunnel tests of several configurations are reported. In addition, applications of wing and...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CONFIGURATIONS, AIRCRAFT DESIGN, AIRFOILS, CIVIL...

Primary efforts directed toward drag reduction centered on the design of both supercritical and subcritical families of airfoils, the reduction of induced drag through the use of vortex diffusers, and the reduction of interference drag for executive-type aircraft.

Topics: NASA Technical Reports Server (NTRS), AIRFOILS, DIFFUSERS, DRAG REDUCTION, STRUCTURAL DESIGN...

Some of the objectives of modern aircraft development are related to the achievement of reduced fuel consumption and aircraft noise. This investigation is mainly concerned with the aerodynamic aspects of aircraft development, i.e., reduction of induced drag. New studies of wing design, and in particular wing tips, are considered. Induced drag is important since, in cruising flight, it accounts for approximately one-third of the entire drag for the aircraft, and one-half while climbing. A survey...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, AIRCRAFT DESIGN, DRAG REDUCTION,...

A two dimensional advanced panel far-field potential flow model of the undistorted, interacting wakes of multiple lifting surfaces was developed which allows the determination of the spanwise bound circulation distribution required for minimum induced drag. This model was implemented in a FORTRAN computer program, the use of which is documented in this report. The nonplanar wakes are broken up into variable sized, flat panels, as chosen by the user. The wake vortex sheet strength is assumed to...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CONFIGURATIONS, AERODYNAMIC DRAG, AIRCRAFT WAKES,...

A procedure has been developed to calculate the effects of blowing two jets over a swept tapered wing at low subsonic speeds. The algorithm used is based on a vortex lattice representation of the wing lifting surface and a line sink-source distribution to simulate the effects of the jet exhaust on the wing lift and drag. The method is limited to those cases where the jet exhaust does not intersect or wash the wing. The predictions of this relatively simple procedure are in remarkably good...

Topics: NASA Technical Reports Server (NTRS), INTERFERENCE LIFT, JET EXHAUST, SUBSONIC FLOW, SWEPT WINGS,...

Gravity waves and their associated breaking into turbulence are very important in producing the overall picture of middle atmosphere global dynamics and associated transport. It is shown in this research that MST radars represent a most powerful technique for obtaining the needed parameters for gravity-wave-induced drag and diffusion effects as well as measuring wave accelerations and diffusion directly. A mathematical solution to this problem is that of radiative equilibrium with a balanced...

Topics: NASA Technical Reports Server (NTRS), ANTENNA RADIATION PATTERNS, GRAVITY WAVES, MIDDLE ATMOSPHERE,...

Some applications of the vortex-lattice theory to the preliminary aerodynamic design and analysis of subsonic aircraft were presented. These methods include the Rockwell-Tulinius vortex-lattice theory for estimating aerodynamic characteristics, a Trefftz plane optimization procedure for determining the span loads for minimum induced drag, and a modification of the Trefftz plane procedure to estimate the induced drag for specified span loads. The first two methods are used to aerodynamically...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CONFIGURATIONS, AIRCRAFT DESIGN, LATTICES...

Variable camber actuator assemblies broaden the range of speeds at which lift to drag performance is maximized for slotted flap wings. Lift is improved over a broader range of cruising speeds by varying wing camber with rotational flap movements that do not introduce wing slots and induced drag. Forward flaps are secured to forward flange links which extended from, and are a part of forward flap linkage assemblies. The forward flaps rotate about flap pivots with their rotational displacement...

Topics: NASA Technical Reports Server (NTRS), LIFT DRAG RATIO, VARIABILITY, WING CAMBER, WING FLAPS, WING...

The design is presented of an aircraft which employs an integrated wing and winglet lift system. Comparison was made with a conventional baseline configuration employing a high-aspect-ratio supercritical wing. An optimized wing-winglet combination was selected from four proposed configurations for which aerodynamic, structural, and weight characteristics were evaluated. Each candidate wing-winglet configuration was constrained to the same induced drag coefficient as the baseline aircraft. The...

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT CONFIGURATIONS, AIRCRAFT DESIGN, COMMERCIAL...

The fundamental vortex theory for a single rotation propeller with a finite number of blades is reviewed. The theory leads to the specification of a radial distribution of bound circulation on each blade for minimum induced loss, analogous to the elliptic spanwise distribution of bound circulation on a wing for minimum induced drag. A propeller designed in accord with this theory has been tested in a water tunnel where it exhibited high efficiency in spite of localized cavitating flow. A...

Topics: NASA Technical Reports Server (NTRS), DRAG REDUCTION, FLOW DISTRIBUTION, PROPELLER BLADES,...

This viewgraph presentation reviews the minimum induced drag of wings. The topics include: 1) The History of Spanload Development of the optimum spanload Winglets and their implications; 2) Horten Sailplanes; and 3) Flight Mechanics & Adverse yaw.

Topics: NASA Technical Reports Server (NTRS), INDUCED DRAG, MINIMUM DRAG, WINGS, WING SPAN, GLIDERS, YAW,...

An analysis of basic vehicle characteristics required to meet the Fundamental Aeronautics Program s 70 percent energy consumption reduction goal for commercial airliners in the 2030 to 2035 timeframe was conducted. A total of 29 combinations of vehicle parasitic drag coefficient, vehicle induced drag coefficient, vehicle empty weight and engine Specific Fuel Consumption were used to create sized tube-and-wing vehicle models. The mission fuel burn for each of these sized vehicles was then...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC COEFFICIENTS, COMMERCIAL AIRCRAFT, ENERGY...

Of all the types of drag, induced drag is associated with the creation and generation of lift over wings. Induced drag is directly driven by the span load that the aircraft is flying at. The tools by which to calculate and predict induced drag we use were created by Ludwig Prandtl in 1903. Within a decade after Prandtl created a tool for calculating induced drag, Prandtl and his students had optimized the problem to solve the minimum induced drag for a wing of a given span, formalized and...

Topics: NASA Technical Reports Server (NTRS), INDUCED DRAG, MINIMUM DRAG, TAIL ASSEMBLIES, AERODYNAMICS,...

The integral conservation laws of fluid mechanics are used to assess the drag efficiency of lifting wings, both CTOL and various out-of-plane configurations. The drag-due-to-lift is separated into two major components: (1) the induced drag-due-to-lift that depends on aspect ratio but is relatively independent of Reynolds number; (2) the form drag-due-to-lift that is independent of aspect ratio but dependent on the details of the wing section design, planform and Reynolds number. For each...

Topics: NASA Technical Reports Server (NTRS), CONSERVATION LAWS, DRAG REDUCTION, FLUID MECHANICS, LIFT,...

Aircraft travel has become a major form of transportation. Several of our major airports are operating near their capacity limit, increasing congestion and delays for travelers. As a result, the National Aeronautics and Space Administration (NASA) has been working in conjunction with the Federal Aviation Administration (FAA), airline operators, and the airline industry to increase airport capacity without sacrificing public safety. One solution to the problem is to increase the number of...

Topics: NASA Technical Reports Server (NTRS), FLIGHT TESTS, VORTICES, MOMENT DISTRIBUTION, AIRCRAFT WAKES,...

Classical drag equations were used to calculate total and induced drag and ratios of stabilizer lift to wing lift for a variety of conventional and canard configurations. The Flight efficiencies of such configurations that are trimmed in pitch and have various values of static margin are evaluated. Classical calculation methods are compared with more modern lifting surface theory.

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, CANARD CONFIGURATIONS, DRAG MEASUREMENT,...

Considered apart from its propulsive system the high altitude airplane itself adapted to higher flight altitudes than those in current use. Scaling on the assumption of constant aircraft density indicates that this conclusion applies most importantly to smaller transport aircraft. Climb to 60,000 ft could save time and energy for trips as short as 500 miles. A discussion of the effect of winglets on aircraft efficiency is presented. A 10% reduction of induced drag below that of a comparable...

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT DESIGN, DRAG REDUCTION, HIGH ALTITUDE, TRANSPORT...

A theoretical method was developed for determining the optimum span load distribution for minimum induced drag for subsonic nonplanar configurations. The undistorted wing wake is assumed to have piecewise linear variation of shed vortex sheet strength, resulting in a quadratic variation of bound circulation and span load. The optimum loading is obtained either through a direct technique, whereby derivatives of the drag expression are calculated analytically in terms of the unknown wake vortex...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CONFIGURATIONS, DRAG, INDUCED DRAG, SUBSONIC...

The feasibility was studied of modifying a JetStar airplane into a demonstrator of benefits to be achieved from incorporating active control concepts in the preliminary design of transport type aircraft. Substantial benefits are shown in terms of fuel economy and community noise by virtue of reduction in induced drag through use of a high aspect ratio wing which is made possible by a gust alleviation system. An intermediate configuration was defined which helps to isolate the benefits produced...

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT DESIGN, CONTROL EQUIPMENT, CONTROL THEORY, DRAG...

The spanwise vortex-lattice arrangement is mathematically established by lattice solutions of the slender wing which are shown to be analogous to the chordwise vortex-lattice thin wing solution. Solutions for any number N of panels wing theory lift and induced drag and thin wing theory lift and moment are predicted exactly. As N approaches infinity, the slender wing elliptic spanwise loading and thin wing cotangent chordwise loading are predicted, which proves there is mathematical convergence...

Topics: NASA Technical Reports Server (NTRS), ANALYTIC FUNCTIONS, LATTICES (MATHEMATICS), OPTIMIZATION,...

A new method based on vortex lattice theory has been developed which can be applied to the combined analysis, induced drag optimization, and aerodynamic design of three-dimensional configurations of arbitrary shape. Geometric and aerodynamic constraints can be imposed on both the optimization and the design process. The method is compared with several known analytical solutions and is applied to several different design and optimization problems, including formation flight and wingtip fins for...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CONFIGURATIONS, AIRCRAFT DESIGN, LATTICES...

Equations are derived to demonstrate which distribution of lifting elements result in a minimum amount of aerodynamic drag. The lifting elements were arranged (1) in one line, (2) parallel lying in a transverse plane, and (3) in any direction in a transverse plane. It was shown that the distribution of lift which causes the least drag is reduced to the solution of the problem for systems of airfoils which are situated in a plane perpendicular to the direction of flight.

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, AIRFOIL PROFILES, AIRFOILS, DRAG REDUCTION,...

Munk's stagger theorem holds that the induced drag of a multiplane is independent of the streamwise position (the stagger) of its lifting elements so long as the gap/span ratios and the element/element lift ratios are specified. In particular, a monoplane-tailplane or a monoplane-foreplane (canard)arrangement can be regarded as a biplane of zero gap and the trim drag due to tailplane download or foreplane upload can be readily calculated. The trim drag penalty is the same for both...

Topics: NASA Technical Reports Server (NTRS), BODY-WING AND TAIL CONFIGURATIONS, DRAG REDUCTION, ESTIMATES,...

Theoretical and practical aspects of conducting three-dimensional wake measurements in large wind tunnels are reviewed with emphasis on applications in low-speed aerodynamics. Such quantitative wake surveys furnish separate values for the components of drag, such as profile drag and induced drag, but also measure lift without the use of a balance. In addition to global data, details of the wake flowfield as well as spanwise distributions of lift and drag are obtained. The paper demonstrates the...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, AERODYNAMICS, INDUCED DRAG, LOW SPEED,...

The AEROX aerodynamic computer program which provides accurate predictions of induced drag and trim drag for the full angle of attack range and for Mach numbers from 0.4 to 3.0 is described. This capability is demonstrated comparing flight test data and AEROX predictions for 17 different tactical aircraft. Values of minimum (skin friction, pressure, and zero lift wave) drag coefficients and lift coefficient offset due to camber (when required) were input from the flight test data to produce...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC COEFFICIENTS, COMPUTER PROGRAMS, INDUCED DRAG,...