Browse Topic: Canards

Items (45)

An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications

04/19/2023

In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid mechanics

Burgers, Phillip

Numerical Analysis of Asymmetric Canard-Wing System in Detroit Flying Cars

2019-01-136103/19/2019

A numerical simulation system of airflow around the Detroit Flying Cars-Wild Dream 1 (WD-1) is introduced. It involves the application of FVM, the mesh-independence system, boundary conditions and the verification of the simulation conditions to NACA airfoil data and the discussion of technological treatments corresponding to the evaluation of asymmetric wings. The present work is investigating the aerodynamic behavior of an asymmetric canard-wing system used on the Detroit Flying Cars-WD 1 model. The work involves the application of Finite Volume Method (FVM), the mesh-independence system, boundary conditions and the verification of simulation conditions to NACA airfoil data using OpenFOAM software. The Reynolds number based on free stream velocity and root chord is 5X106. Based on the Coefficient of Lift and Coefficient of Drag obtained from the analysis, the effect of canards on the wings, the distance between the canard trailing edge and the leading edge of the wings and the

Kocherla, Isaac Shanth, Yu, ChenXing

Flight and Range Characteristics for a Subsonic Advanced Propeller-Driven Blended Wing Body Composite Air Frame Capable of Transporting a 150-Ton Military Cargo

2016-01-2019

09/20/2016

An advanced composite Blended Wing Body (BWB) air frame previously used as a study aircraft to transport a 75-ton military cargo halfway around the world and back unrefueled has been modified and evaluated as a 150-ton heavy lifter. The modifications include enlarging the forward trim canard, reducing fuel load by 151,850 lbs, increasing the high-mach NASA-type counter-rotating propellers from 12 feet to 13 feet diameter, extending the propeller support pylons' height by 6 inches and modifying cruise flight and prop control strategies. Due to structural and propulsion system changes, the air frame Operational Empty Weight (OEW) was increased by 1,850 lbs. but the maximum Take Off Gross Weight (TOGW) was held to 800,000 lbs. Brief descriptions of the major propulsion system components are provided. In addition, a comparison of three different counter-rotating propeller systems is presented. The first is a Standard configuration. The second Modified (Mod.) configuration uses a proposed

Johnston, Richard P.

Pugh Analysis for Configuration Selection of a Hybrid Buoyant Aircraft

2015-01-2446

09/15/2015

In comparison with traditional aircraft design, the configuration design phase of a hybrid buoyant aircraft is quite complex due to the augmentation of aerostatic and aerodynamic lift. The first step in assessing the optimal configuration for such aircraft is to approach the design in a number of different ways with different shapes of hull and diversed empennage arrangements. Concept selection methods like Pugh concept selection charts can assist to rank the population of different concepts of such aircraft. In the present work, an effort was done to explore the potential usage of Pugh's method in a comprehensive manner and to establish a basis for choosing a particular design concept. Driving factors of such design concepts were reviewed alongwith the selection of figure of merits, which were further evaluated by taking Megalifter as a reference with which all other configurations under consideration were compared. The initial set of concept generation was obtained on some initial

ul Haque, Anwar, Asrar, Waqar, Sulaeman, Erwin, Omar, Ashraf, Ali, Jaffar Syed Mohamed

Novel World War II Aircraft Design Features

2015-01-2580

09/15/2015

During the 1930s and 1940s, aircraft designers worked on developing novel design features. Some of these features worked and are commonplace today. Other features fell by the wayside and have been forgotten. These novel design features include laminar flow wings, low-drag cooling systems, buried propulsion systems, canard configurations, jet engines, break-away wing tips, pressure cabins and swept wings. The development and applications of these features will be examined. Specific technical details of these applications will be included in this examination. For the design features that fell by the wayside, the reasons for this outcome will be discussed

Lednicer, David

Multifunctional Unmanned Reconnaissance Aircraft for Low-Speed and STOL Operations

2015-01-2465

09/15/2015

This paper presents a novel UAS (Unmanned Aerial System) designed for excellent low speed operations and VTOL performance. This aerial vehicle concept has been designed for maximizing the advantages by of the ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle) propulsion system, which has been studied in a European commission under 7th framework programme. This UAS concept has been named MURALS (acronym of Multifunctional Unmanned Reconnaissance Aircraft for Low-speed and STOL operation). It has been studied as a joint activity of the members of the project as an evolution of a former concept, which has been developed during 80s and 90s by Aeritalia and Capuani. It has been adapted to host an ACHEON based propulsion system. In a first embodiment, the aircraft according to the invention has a not conventional shape with a single fuselage and its primary objective is to minimize the variation of the pitching moment allowing low speed operations. The shape with convex wings has

Trancossi, Michele, Bingham, Chris, Capuani, Alfredo, Das, Shyam, Dumas, Antonio, Grimaccia, Francesco, Madonia, Mauro, Pascoa, Jose, Smith, Tim, Stewart, Paul, Subhash, Maharshi, Sunol, Anna, Vucinic, Dean

Aerodynamic Flat and Curved Plates, Combined

2012-36-020710/02/2012

Flat plate aerodynamic profiles which have constant thicknesses were intensively used at the beginning of aviation, especially on canards and stabilizers. Today, the constant thickness is usually a necessity borne of the manufacturing process, because the blades are made out of steel plates, in most of the cases. These profiles are used on some domestic ventilation and air conditioning fans and as wing profiles for balsa wood rubber band model airplanes. A more efficient spin off of the flat plate profile, the curved plate, of constant thickness and curvature, has found wide application in fans for industrial use, automotive cooling systems, air conditioning and in carbon fiber propellers and rotors of Unmanned Air Vehicles, UAVs, especially electric mini-quadrotors. However, there is enough evidence that combining the curved plate profile with flat plate profile does bring better results than the current days use of constant curvature profiles very intensively. This paper shows that

Rabello, Jose Esteves Botelho

CFD Analysis of Directional Stability for the American Challenger Rocket Car

2007-01-385709/17/2007

This paper describes how computational fluid dynamics (CFD) has recently been used to design the directional stability components of the American Challenger racecar. Under development by Bill Fredrick, the missile-shaped, rocket-powered car is intended to break the World Land Speed Record, achieving a top speed greater than 800 mph. Designing a transonic car presents many unique challenges that are almost never encountered by land vehicles or aircraft. Previous papers [1, 2] on this project have described the use of the CFD++ flow solver in the selection of a rear strut profile and the positioning of the canard to achieve the desired pitching characteristics and aerodynamic loading. Following completion of these phases, the directional stability was examined at several sideslip angles and through a large range of speeds. As with previous phases of the design, maintaining desirable aerodynamic performance through both subsonic and transonic flow regimes is difficult. While directional

Oberoi, R., Chakravarthy, S., Peroomian, O., Akdag, V., Fredrick, W., Glessner, P.T.

Using CFD to Design the American Challenger Rocket Car

2006-01-366012/05/2006

This paper details how computational fluid dynamics (CFD) is being used to design the American Challenger car, under development by Bill Fredrick. This rocket-powered vehicle is intended to set a new world land speed record. Initially, CFD revealed that a biconvex-shape airfoil for the canard and rear strut had advantages over a diamond profile because it limited large-amplitude oscillations caused by transonic shock boundary layer interactions. Later, CFD helped identify proper placement and orientation of the canard and strut to achieve the desired down force and stability. The use of CFD simulations with both propulsion on and off have helped to ensure that the vehicle will have the desired dynamic characteristics at all phases of the record breaking attempts: acceleration, record phase, and deceleration to full stop

Oberoi, R., Chakravarthy, S., Fredrick, W., Glessner, P.T.

Excitations for Rapidly Estimating Flight-Control

TBMG-9307/01/2006

A flight test on an F-15 airplane was performed to evaluate the utility of prescribed simultaneous independent surface excitations (PreSISE) for real-time estimation of flight-control parameters, including stability and control derivatives. The ability to extract these derivatives in nearly real time is needed to support flight demonstration of intelligent flight-control system (IFCS) concepts under development at NASA, in academia, and in industry. Traditionally, flight maneuvers have been designed and executed to obtain estimates of stability and control derivatives by use of a post-flight analysis technique. For an IFCS, it is required to be able to modify control laws in real time for an aircraft that has been damaged in flight (because of combat, weather, or a system failure

Conformably Stowable Canard

TBMG-29542

02/01/2001

An improved secondary wing system of the canard type has been invented to improve performance and increase efficiency of airplanes capable of flight at supersonic and high subsonic speeds. Canards, including small forward-mounted secondary wings, are used to increase the total wing surface areas of airplanes in order to improve their low-speed lift-to-drag ratios and trim characteristics. Although canards have been used on supersonic airplanes to increase low-speed performance, heretofore the designs of canards have not provided for optimal high-speed performance and aerodynamic efficiency

Compound Tilting Wing for STOL Configurations

1999-01-565410/19/1999

An empirically based, analytical tool for calculating lift, drag and pitching moment of tilting wing configurations is presented, and used to develop the general characteristics of the Compound Tilting Wing (CTW), a variation on the conventional tilting wing configuration. The CTW utilizes an inboard leading edge extension, which acts as a canard when the wing tilts to augment pitch control during low speed operations and conforms to the wing at zero tilt. This scheme allows the designer more degrees of freedom for overall configuration layout and propulsion system integration for STOL design

Shenk, Barth W.

X-36 Tailless Agility Aircraft Subsystems Integration

97550510/01/1997

The X-36 is a remotely piloted 28% scale model of a two-axis-unstable notional future fighter aircraft with canards, a mid-wing and features the absence of any vertical control surfaces, Figure 1. The aircraft was jointly developed by the NASA Ames Research Center and McDonnell Aircraft & Missile Systems and flight tested at the NASA Dryden Flight Research Center. Objectives of this program were to demonstrate fighter aircraft agility for a vertical tailless configuration and to demonstrate the development of a low cost alternative to full size prototype aircraft. This paper presents some aspects of the subsystem integration methodology used to develop the X-36 Tailless Agility Research Aircraft

Harris, Willard J.

Hover/Ground-Effect Testing and Characteristics for a Joint Strike Fighter Configuration

96225311/18/1996

Hover and ground-effect tests were conducted with the Lockheed-Martin Large Scale Powered Model (LSPM) during June-November 1995 at the Outdoor Aerodynamics Research Facility (OARF) located at NASA Ames Research Center. This was done in support of the Joint Strike Fighter (JSF) Program being lead by the Department of Defense. The program was previously referred to as the Joint Advanced Strike Technology (JAST) Program. The tests at the OARF included: engine thrust calibrations out of ground effect, measurements of individual nozzle jet pressure decay characteristics, and jet-induced hover force and moment measurements in and out of ground effect. The engine calibrations provide data correlating propulsion system throttle and nozzle settings with thrust forces and moments for the bare fuselage with the wings, canards, and tails removed. This permits measurement of propulsive forces and moments while minimizing any of the effects due to the presence of the large horizontal surfaces. The

Hange, Craig, Naumowicz, Tim, Wardwell, Doug, Margason, Richard, Arledge, Tom

An Assessment of a Reaction Driven Stopped Rotor/Wing Using Circulation Control in Forward Flight

96561210/01/1996

The desire of achieving faster cruise speed for rotorcraft vehicles has been around since the inception of the helicopter. Many unconventional concepts have been considered and researched such as the advanced tilt rotor with canards, the tilt-wing, the folding tiltrotor, the coaxial propfan/folding tiltrotor, the variable diameter tiltrotor, and the stopped rotor/wing concept, in order to fulfill this goal. The most notable program which addressed the technology challenges of accomplishing a high speed civil transport mission is the High Speed Rotorcraft Concept (HSRC) program. Among the long list of potential configurations to fulfill the HSRC intended mission, the stopped rotor/wing is the least investigated due to the fact that the existing rotorcraft synthesis codes cannot handle this type of vehicle. In order to develop such a tool, a designer must understand the physics behind this unique concept. The uniqueness of stopped rotor/wing vehicles that use reaction drive can be found

Tai, Jimmy C., Mavris, Dimitri N., Schrage, Daniel P.

Conceptual Airplane Design with Automatic Surface Generation

96551710/01/1996

A methodology and software to automatically define airplane configurations is presented. The general airplane configuration has wing, fuselage, vertical tail, horizontal tail, canard, pylon, and engine nacelle components. The wing, tail, canard, and pylon components are manifested by solving a fourth order partial differential equation subject to Dirichlet and Neumann boundary conditions. The design variables are incorporated into the boundary conditions, and the solution is expressed as a Fourier series. The fuselage and nacelles are described with analytic equations. The methodology is called Rapid Airplane Parametric Input Design (RAPID), and both batch and interactive software based on the technique are described. Examples of high-speed civil transport configurations and subsonic transport configurations are presented

Smith, Robert E., Cordero, Yvette, Mastin, Wayne

CaRnard - A New Roadable Aircraft Concept

93260109/01/1993

The CaRnard* is a new concept in roadable aircraft which takes advantage of the geometric match between the canard aircraft configuration and the mid engine auto. Each high main wing is on a common pivot with one above the other. They rotate forward in a horizontal plane thru an angle of about 110 degrees. In this position they are above and roughly parallel to the fuselage. Each canard also has a pivot near a front corner of the vehicle. They pivot forward about 180 degrees so that one is above the other

Stiles, Palmer

History and Future of Flying Automobiles

92156808/01/1992

The dream of the flying automobile. The distinction between flying autos and roadable aircraft. Examples known to have flown. Safety and accidents. FAA certification of two designs. Drawings from patents. Patents per decade. Indicators of resurging interest. Some people active in the field today. Role of the Experimental Aircraft Association. Current legal climate and its effect on the health of the small aircraft industry. Development and marketing through the experimental aircraft movement with sale of plans or kits to be homebuilt. Use of existing infrastructure for initial small numbers. Numerical specs for ideal design. Geometric match between canard aircraft and rear or mid engine car. Existing canard benchmark design. Proposed model design competition. Bibliography and references

Stiles, Palmer C.

A Short Range Passenger/Freighter Canard - Some Problems of a Preliminary Aerodynamic Concept

92101204/01/1992

The paper presents problems which occurred during a work of the student design team on a preliminary design of a light transport airplane. Some requirement considerations which provided a canard configured concept are presented. The main subject of the work are the problems referring to a preliminary aerodynamic concept and a preliminary configuration optimization of a canard configured aircraft of the considered class. In addition, some remarks on the research and design process are also presented

Piotr, Kulicki, Maciej, Lasek, Jacek, Winiecki

Supersonic Aerodynamic Characteristics of a Maneuvering Canard-Controlled Missile with Fixed and Free-Rolling Tail Fins

90199309/01/1990

Wind tunnel investigations were conducted on a generic cruciform canard-controlled missile configuration. The model featured fixed or free-rolling tail-fin afterbodies to provide an expanded aerodynamic data base with particular emphasis on alleviating large induced rolling moments and/or for providing canard roll control throughout the entire test angle-of-attack range. The tests were conducted in the NASA Langley Unitary Plan Wind Tunnel at Mach numbers from 2.50 to 3.50 at a constant Reynolds number per foot of 2.00 × 106. Selected test results are presented to show the effects of a fixed or free-rolling tail-fin afterbody on the static longitudinal and lateral-directional aerodynamic characteristics of a canard-controlled missile with pitch, yaw, and roll control at model roll angles of 0° and 45

Blair, A. B.

Stability Characteristics of a Conical Aerospace Plane Concept

892313

09/01/1989

Wind tunnel investigations were conducted as part of an effort to develop a stability and control database for an aerospace plane concept across a broad range of Mach numbers. The generic conical design used in these studies represents one of a number of concepts being studied for this class of vehicle. The baseline configuration incorporated a 5° cone forebody, a 75.96° delta wing, a 16°leading-edge sweep deployable canard and a centerline vertical tail. Tests were conducted in the following NASA-Langley facilities spanning a Mach range of 0.1 to 6:30- by 60-Foot Tunnel,14- by 22-Foot Subsonic Tunnel, Low Turbulence Pressure Tunnel, National Transonic Facility, Unitary Plan Wind Tunnel, and the 20 Inch Mach 6 Tunnel. Data were collected for a number of model geometry variations and test conditions in each facility. This paper highlights some of the key results of these investigations pertinent to stability considerations about all three axes. The effects of the canard on pitch

Hahne, David E., Luckring, James M., Covell, Peter F., Phillips, W. Pelham, Gatlin, Gregory M., Shaughnessy, John D., Nguyen, Luat T.

A VSAERO Analysis of Several Canard Configured Aircraft - Part 2

89228709/01/1989

This paper reports on the analysis of several further canard configured aircraft using the VSAERO low-order panel method. Aircraft analyzed within include the Rutan VariEze, Defiant, Predator, Catbird and Triumph. In all cases VSAERO models of the complete aircraft have been used to calculate the aerodynamic performance of the aircraft. Comparisons of these results with flight test and wind tunnel data are included where data are available. Results presented herein show VSAERO to be reasonably accurate in predicting aircraft neutral point. Induced drag predictions tend to be inconsistent and future incorporation of a Trefftz Plane in VSAERO will probably rectify these problems. Overall, VSAERO is shown to be a useful tool for the aircraft design process

Lednicer, David

Wind-Tunnel Investigation of the Low-Speed Aerodynamics of Slender Accelerator-Type Configurations

88135610/01/1988

An investigation was conducted in the Langley 14- by 22-Foot Subsonic Tunnel to determine the low-speed aerodynamic characteristics of a generic, hypersonic accelerator-type configuration. The model consisted of a delta wing configuration incorporating a conical forebody, a simulated wrap-around engine package, and a truncated conical aftbody. Six-component force and moment data were obtained over a range of angle of attack from -4° to 30° and for a sideslip range of ±20°. In addition to tests of the basic configuration, component build-up tests were conducted; and the effects of power, forebody nose geometry, a canard surface, fuselage strakes, and lower surface engines alone were also determined. Control power was investigated via the testing of wing flap deflections as well as the deflections of an aftbody flap in the exhaust flow. Surface pressure data were obtained at several longitudinal locations along the conical forebody. Surface oil flows and a smoke flow visualization

Gatlin, Gregory M.

X-29A Subsystems Integration - An Example for Future Aircraft

88150410/01/1988

The X-29A is the first X-series experimental aircraft developed in the United States since the mid-sixties. The X-29A is a technology demonstrator aircraft that integrates several different-technologies into one airframe. Among the technologies demonstrated are the aeroservoelastically tailored composite forward swept wings, close coupled canards, discrete variable camber wing, triplex digital flight control system with analog backup, thin supercritical wing, three surface pitch control, large negative static margin and the integration of these technologies into the X-29 airframe. This paper deals with the issue of technology integration of five of the X-29A subsystems and the early design decision to use existing aircraft, components whenever and wherever possible. The subsystems described are the X-29 aircraft Hydraulics System, the Electrical Power System, the Emergency Power System, the Aircraft Mounted Accessory Drive and the Environmental Control System. The decision, to use

Collins, Edward

A VSAERO Analysis of Several Canard Configured Aircraft

88148510/01/1988

This paper reports the results of an analysis of several canard configured aircraft using the VSAERO low-order panel method. Aircraft analyzed within include the Rutan Long EZ, Solitaire, VariViggen, VariViggen SP and Quickie homebuilt aircraft. The use of VSAERO in the development of the Rutan Voyager is also discussed. In all cases VSAERO models of the complete aircraft have been used to calculate the aerodynamic performance of the aircraft. Comparisons of these results with flight test data are included where data are available. Aerodynamic panelling programs such as VSAERO allow the determination of an aircraft's induced drag. To substantiate this methodology comparisons of results with the classical Prandtl-Munk theory and wind tunnel test results are also included. These comparisons validate the use of VSAERO in the prediction of induced drag. Further comparisons with flight test results for several aircraft are included

Lednicer, David

What Drives Unique Configurations

88135310/01/1988

This paper presents examples of how severe and/or novel design requirements can ‘drive’ an airplane designer to select a ‘unique’ configuration. Examples to illustrate this are given for the flying wing, for two- and for three-surface canards and for joined wing airplane configurations. Brief historical reviews are also provided

Roskam, Jan

A Close-Coupled Canard, Technology Demonstration Aircraft for General Aviation Applications

87188310/01/1987

From the literature, theoretical analyses and subscale windtunnel aerodynamic investigations of canard aircraft configurations indicate benefits which are enhanced by close-coupling the canard to the wing. To properly evaluate the advantages and to investigate some solutions to the problems associated with the close-coupled canard, a full-scale aircraft development was initiated. A dual purpose of this development was to create a proof-of- concept vehicle designed to satisfy a general aviation requirement, and demonstrate a subsonic, close-coupled canard technology. This paper describes the development together with the aerodynamic considerations of the design. Ultimately, flight-test data are to be used in establishing correlations with windtunnel model data and analytical methodology

Martin, Joe. D., Foster, Ned R.

Canard Certification Loads — A Review of FAA Concerns

87184710/01/1987

Since the first airplane was certified in 1927, the standard configuration has been with the main lifting surface or surfaces forward of the stabilizing surface. Although some of the advantages of the canard configuration were recognized quite early - by the Wright Brothers, for example - canard surfaces have been used to date only as additional control surfaces on some military airplanes, and on some amateur built airplanes. As a result, the Airworthiness Regulations of Reference 1 address only tail aft configurations. When FAA was first approached regarding certification of a canard configured small airplane, an FAA/Industry Empennage Loads Working Group was formed to develop technical proposals for the necessary rule changes and policy. The concerns addressed by this working group are discussed in the following sections

Barnes, Terence J., Gabriel, Edward A.

Flight Test Results for Several Light, Canard-Configured Airplanes

87180110/01/1987

Brief flight evaluations of two different, light, composite constructed, canard and winglet configured airplanes were performed to assess their handling qualities; one airplane was a single engine, pusher design and the other a twin engine, push-pull configuration. An emphasis was placed on the slow speed/high angle of attack region for both airplanes and on the engine-out regime for the twin. Mission suitability assessment included cockpit and control layout, ground and airborne handling qualities, and turbulence response. Very limited performance data was taken. Stall/spin tests and the effects of laminar flow loss on performance and handling qualities were assessed on an extended range, single engine pusher design

Brown, Philip W.

The X-29 - a Unique and Innovative Aerodynamic Concept

85177112/01/1985

Grumman Corporation, under a contract sponsored by the Defense Advanced Research Projects Agency (DARPA) and monitored by the United States Air Force, has designed, fabricated, and is jointly flight testing the X-29 Advanced Technology Demonstrator with NASA. The X-29 was conceived to demonstrate in-flight the potential advantages of several advanced and innovative technologies integrated into one vehicle design. These advanced technologies include: A forward-swept wing (FSW) employing a thin supercritical airfoil Aeroelastically-tailored composite wing covers to control divergence A close-coupled, variable-incidence canard Variable wing camber Three-surface trim configuration. An aerodynamic overview of the configuration development and integration of these technologies is presented. Wind tunnel results and flight test results, where available, are also presented to substantiate the advantages of these innovative concepts

Frei, D., Moore, M.

Application of the Vortex-Lattice Method to High-Angle-of-Attack Subsonic Aerodynamics

85181710/01/1985

The vortex-lattice method for general, unsteady, incompressible aerodynamics is described. This method can treat multiple lifting surfaces operating in close proximity, fully accounting for interference. It is not limited by planform, camber, twist, or maneuver as long as separation occurs only along known lines and vortex bursting does not occur near one of the lifting surfaces. Steady flows can be treated efficiently as special cases of uniform motion. Several examples are presented as a partial illustration of the range of problems that can be treated. These include steady and unsteady flows over rectangular and delta wings, a numerical simulation of the wingrock phenomenon, and steady and unsteady interference among two canards and a wing. In the numerical simulation of wingrock, the equation governing the motion of a delta wing mounted on a free-to-roll sting is integrated numerically by a predictor-corrector method with the aerodynamic roll moment being supplied by the vortex

Mook, Dean T., Nayfeh, Ali H.

Interdependence of Parameters important to the Design of Subsonic Canard-Configured Aircraft

85086504/01/1985

An analysis is made of the interrelation-ship of the longitudinal parameters important to the aerodynamic design of an efficient canard or tandem wing configuration. It is shown that theoretical configuration span efficiencies substantially greater than one are feasible with the proper choice of parameters. This improvement can translate into significantly increased lift/drag ratios assuming fixed spans. The Prandtl-Munk relationship for induced drag is used as a convenient qualitative guide, with stability and trim criteria superimposed. An “aspect-ratio ratio” parameter is introduced to aid in optimizing a configuration longitudinally. It is shown that a canard/wing “aspect-ratio ratio” of approximately 3/2 to 2 is necessary to achieve peak span efficiency for a given span ratio and gap, assuming representative parameters. Large lifting tails are treated in the appendix; they are shown to be aerodynamically competitive with canards for the lower range of span ratios (<̄0.7-0.8

Feistel, T. W.

Analytical Study of Three-Surface Lifting Systems

85086604/01/1985

Conventional, canard, and three surface aircraft configurations are investigated analytically to determine each configuration's induced drag, as well as the pressure and viscous drag. A vortex panel method in conjunction with momentum integral boundary layer method is used to predict inviscid and viscous characteristics. Vortex lattice methods are used to trim the aircraft as well as to predict the induced drag of each configuration. Viscous and induced drag results are presented for two different payloads, a six-place and a twelve-place configuration. For both payloads the conventional configuration had the highest lift over drag. However, the canard and the three surface were close enough to warrant consideration based on other criteria

Rokhsaz, Kamran, Selberg, Bruce P.

A Design Approach to Integrated Flight and Propulsion Control

831482

10/03/1983

A decentralized, multivariable controls methodology is being developed for the functional integration of a fighter's aerodynamic controls with those of its propulsion system (inlet, engine, and thrust vectoring/reversing nozzle). Integrated controls account for, and take advantage of the significant cross-coupling between these system elements. A high-fidelity, six-degrees-of-freedom (6 DOF) aircraft simulation has been developed, incorporating advanced tactical fighter features such as variable cycle engines, variable geometry inlets, 2D-CD TV/TR nozzles, canards and a propulsive lift concept. A comprehensive evaluation test plan, including a piloted simulation, has been developed to validate this integrated-controls design methodology. Preliminary results show significant benefits of integrated control in terms of enhanced aircraft maneuverability, precise flight path control, reduced pilot workload, and fault tolerant system design