Generalized liftingline theory for curved and swept wings 499 2. Although the naca conducted independent wind tunnel research on variable sweep wings in 1945, the x5 originated with the messerschmitt p. Computations performed for the boundary layer on a natural laminar flow airfoil with a leadingedge sweep angle of 34. Theses numerical experiments show that the forward swept wing is capable of achieving more optimal perching trajectories that require less actuator effort.
The characteristics of swept wings illustrate the reason for variable sweep in some advanced aircraft and a comparison made with jet lift. In other cases the use of variable geometry wings, as on the grumman f14 tomcat, allows an aircraft to. Some of the implications and problems involved in variable sweep. This is why aircraft such as the f14 tomcat and panavia tornado make use of a variable sweep or swing wing to optimize both for supersonic performance and subsonic maneuverability. Johnson airplane with variable swepi wings y june 4, 1957 3 sheets. Us5984231a aircraft with variable forwardsweep wing. This is why it is beneficial to use variable swept wings for some. It allows the aircrafts shape to be modified in flight, and is therefore an example of a variable geometry aircraft. Thrustvectoring devices extend from the jet engines of the aircraft for varying the thrust direction of such engines. Pdf methodologies for preliminary design of variable wing. Dre technology for extending swept wing natural laminar flow at chord reynolds numbers relevant to transport aircraft. Estimated benefits of variablegeometry wing camber. American institute of aeronautics and astronautics 12700 sunrise valley drive, suite 200 reston, va 201915807 703. The wing model is based on the roddenlove forward swept wing which is modified in the present work so that it.
Variable sweep wing design the starting point for our wing morphing aircraft was the lowcost. Wing planform design as pointed out in the previous section, swept vsings with conventional straightedged planforms have two principal defects in the transonic speed range. A variable swept wing aircraft would be equivalent to a series of such experimental air craft, as it could change the wing angle to the desired research objectives. The term variable geometry wing is often used synonymously with variable sweep, though strictly speaking it is a type of variable geometry. Panavia tornado variablesweep wing combat aircraft. In order to achieve both sonic boom suppression and a reduction in wavedrag, the entire airplane shape of the supersonic aircraft of the present invention uses a variable forward swept wing configuration. It is an object of the present invention to provide the entire airplane shape of a supersonic aircraft that can realize low sonic boom characteristics, and that can also minimize wavedrag. One is that for any given length of wing, the actual span from tiptotip is shorter than the same wing that is not swept.
Design of forward swept wings activities at dlr first studies in 1990s. Pdf roll control reversal of variable swept wing in. A variable sweep wing main part of variable geometry wing, also known as a swing wing, is an aeroplane wing that may be swept back and then returned to its original position during flight. A swept wing is a wing that angles either backward or occasionally forward from its root rather. Why do some military aircraft use variablesweep wings. Swing wing may be colloquial, but there are many other variable wing features than just swing.
The inertia axis of each wing was variable and the wing could be swept back by rotation about an axis perpendicular to the wing in the plane of the root section. Pdf this study presents one of the methodologies that can be adopted to design variable wing geometry and its functionality. Us4569493a integrated multirole variable sweep wing. The variable forwardswept wing vfsw aircraft is a typical variant aircraft. I propose to discuss the design procedure in its separate.
The variable sweep feature was utilized to provide high levels of. Structural analysis, fatigue analysis and optimization of aircraft wings. Toll united states patent q 3,064,928 vareable sweep wtng aircraft thomas a. A generalized liftingline theory for curved and swept wings. Why do some military aircraft use variable sweep wings. Pdf aeroelastic tailoring of a composite forwardswept. Variable sweep wings thin swept wings of low aspect ratio are part of the aerodynamic ingredients of a lowdrag supersonic aircraft but, at the same time, yield an aircaft with a relatively low maximum liftdrag ratio at subsonic speeds, as well as certain undesirable handling characteristics in the lowspeed, highangleofattack regime. Toll, lancaster, calif, assignor to the united states of america as represented by the administrator of the national aeronautics and space administration filed aug. Manchester and others published a variable forwardsweep wing design. A variable sweep wing, colloquially known as a swing wing, is an airplane wing, or set of wings, that may be swept back and then returned to its original position during flight.
In the unswept position the wing is approximately orthogonal to a fuselage centerline, while in the fullforward sweep position the wing. An aircraft with a variable forwardsweep wing and the method of configuring the wing in an optimal position for a desired flight regime. The development of variable geometry in general is traced as applied to aircraft wings with particular emphasis on variable sweepback, including discussion of some experimental aircraft. If you orient the airfoil to the free stream direction for a swept wing it has the effect of increasing the percentage thickness and percentage camber of the airfoil by the ratio of the chord in the free stream direction to the chord perpendicular to the 25% chord line. Gilyard dryden flight research center edwards, california national aeronautics and space administration dryden flight research. In fact, the articles see also section points to some examples that i would rightly consider variable geometry wings. Aspects of wave drag reduction were covered in the discussion of swept wings in section 7. Manchester and others published a variable forwardsweep wing design for enhanced perching in micro aerial vehicles find, read and cite all the research you need. Aeroelastic tailoring of a composite forward swept wing using a novel hybrid pattern search method article pdf available in journal of aerospace engineering 296. Using throttle in mode 1 to swing back wing as it advances throttle. Aerodynamic design of swept wings and bodies 261 3. A swept wing produces less lift than an equivalent unswept wing which results in both a higher stall speed and a less maneuverable platform.
It allows the aircrafts shape to be modified in flight, and is therefore an example of a variable geometry aircraft a straight wing is most efficient for lowspeed flight, but for an aircraft designed for. Pdf a variable forwardsweep wing design for enhanced. The airflow over a swept wing encounters the wing at an angle. Roll control reversal of a variable swept wing is investigated in the present paper. A micro aerial vehicle with a variable forwardsweep wing is proposed with the goal of enhancing. Theoretical and experimental study of a forward swept wing.
When designing the wing, other wing parameters are determ ined. Theoretical and experimental investigations on finite swept wings show, because of threedimensional displacement effects, an effective increase of wing sweep for backward swept wings and an. Fa37 talon, forward variablesweep wing, nothing is. Use mode 0 to keep wings perpendicular to takeoff and land. A swept wing is a wing that angles either backward or occasionally forward from its root rather than in a straight sideways direction. The dominant feature of the configuration is the nonintegrated variable sweep wing. In the latter case it was found that keeping the pressure uniform over the upper wing surface minimizes the shock strength, thereby reducing wave drag. The analysis of moment characteristics of variable forwardswept. Roll control reversal of variable swept wing in supersonic. The robust scroll design has proven reliability over competing compressor technologies. A variable sweep wing, colloquially known as a swing wing, is an airplane wing, or set of wings, that may be swept back and then returned to its original straight position during flight.
Us20050230531a1 variable forward swept wing supersonic. This is helpful when were building airplanes that have to take off from short runway strips which requires high aspect ratio wings all oth. Different aerodynamic sweep at different speeds, allowing aspect ratio to be varied inflight. Low speed drag is strongly correlated with the aspect ratio, the span compared to chord, so a swept wing always has more drag at lower speeds. That angle can be broken down into two vectors, one perpendicular to the wing, and one parallel to the wing.
Adamczyk united aircraft research laboratories summary an analysis is presented which yields an approximate solution for the unsteady aerodynamic response of an infinite swept wing encountering a vertical oblique gust in a compressible stream. The copeland scroll variable speed compressor utilizes a brushless permanent magnet motor bpm that varies the scroll speed, thus, varying the refrigerant flow. A variable sweep wing swing wing is a type of pivoted wing that takes advantage of the aerodynamics of a swept wing at high speeds while swinging straight to avoiding the drawbacks of such a design at lower speeds. In this context, this is a swing wing article not a variable geometry wing article. The canards are positioned and configured to produce pitch control moments about the center of gravity. Abstract roll control reversal of a variable swept wing is investigated in the present.
The passage of an infinite swept airfoil through an oblique gust by john j. Design of backward swept, turbulent reference wing design of a forward swept, turbulent wing design of a forward swept, laminar wing application of fsw to low noise aircraft configuration. A variable forwardsweep wing design for improved perching in micro aerial vehicles zachary r. The aerodynamic design of swept winged aircraft at. Dreenhanced sweptwing natural laminar flow at high.
Effects of speed on coupled sweep and camber in morphing. The formulation of the problem let us consider a wing operating in an inviscid, incompressible flow. Study of the performance envelope of a variable sweep wing. A variable forwardsweep wing design for improved perching. What are the advantages and disadvantages of variable. The panavia tornado is a family of twinengine, variable sweep wing combat aircraft, which was jointly developed and manufactured by germany, italy and the united kingdom. Estimated benefits of variable geometry wing camber control for transport aircraft alexander bolonkin senior research associate of the national research council dryden flight research center edwards, california glenn b. Based on different mission requirements and flight environments, it can free change. Johnson airplane with variable swept wings june 4, 1957i 3 shetssheet 2 filed april 19, 1.
The variable forwardsweep wing is positionable from an essentially unswept position to a fullforward sweep position. Wing sweep has the effect of delaying the shock waves and accompanying aerodynamic drag rise caused by fluid compressibility near the speed of sound, improving performance. This involves the definition of the wing section and the planform. Variable geometry wing design various types of variable geometry wing design are there. Swept wings are therefore often used on jet aircraft designed to fly at these speeds. Canards are pivotally mounted on the fuselage of a variable sweep wing jet aircraft and project laterally with respect to the fuselage forwardly of the wings.