Course: Aircraft Design and Development
Abstract
The Grumman X-29 aircraft was developed and designed as a technology demonstrator in an attempt to test and evaluate the feasibility of Forward Swept Wings (FSW) aircraft. Theoretical models had indicated the possibility for significant improvements in lift generation, drag mitigation and higher maximum speed. The development of light weight composite materials with high yield strength provided a solution to the problem of structural divergence demonstrated by prior FSW aircraft programs. DARPA, NASA, and the USAF recognized the feasibility of an innovative concept with the potential for higher performance than the conventional backward swept aircraft wings. Despite stability and control challenges, aircraft configured with forward swept wings can achieve optimum flight performance characteristics and stability. How was aircraft design characteristics and enabling technologies optimized to achieve improved maneuverability and stability for the Grumman X-29 ? Wing geometry, movable forward-mounted canards and a computerized fly-by-wire flight control system significantly optimized maneuverability and stability for the Grumman X-29 which reportedly generated better control responses than comparable aircraft at up to 45 degree angle of attack. Stability and maneuverability of the Grumman X-29 can be improved by implementing a variable FSW wing configuration. Any resulting change in maximum speed capabilities can be compensated by the use of a V-tail configuration and a newer engine capable of generating significantly more thrust. Engineers shall also evaluate opportunities for improving stability and control by mounting the Forward Swept Wings (FSW) much closer to the center of gravity of the aircraft. The three points location of the FSW shall support a fuselage and wings system in static equilibrium with the net torque equal to zero. Flight control surfaces such as ailerons, slats, flaps, and strake flaps shall be used as secondary systems to improve aircraft performance and stability.
Introduction
Swept wings were pioneered by the remarkable Messerschmitt Me262 aircraft program. To achieve significantly higher aircraft speed, Me262 engineers develop a backward swept configuration for the aircraft wings and progressively increased the swept angles (Radinger & Schick, 1993). The swept wings design allows for a delay of drag divergence to much higher Mach numbers (Anderson, 2016). Although this type of aircraft wings design configuration is commonly characterized by a backward orientation, a forward orientation is also feasible. A testimony to the feasibility and design of highly efficient aircraft configured with forward swept wings is the Grumman X-29. It is a remarkable aircraft that was designed to take advantages of forward swept wings characteristics such as a minimization of drag and an increase in lift characteristics (NASA, 2015).
Airflow over a forward swept wing cause flow separation to start near the root which prevent the loss of aileron control at the tips. They generate higher magnitude of lift forces and produce higher lift coefficient and maximum lift coefficient (Anderson, 2016). According to NASA, the reverse airflow also keeps the wing tips and ailerons from stalling at high angles of attack. This surprisingly renders more maneuverable aircraft configured with forward swept wings (NASA, 2016). Despite stability and control challenges, aircraft configured with forward swept wings can achieve optimum flight performance and stability. How was aircraft design characteristics and enabling technologies optimized to achieve improved maneuverability and stability for the Grumman X-29 ?
Wing geometry, movable forward-mounted canards and a computerized fly-by-wire flight control system significantly optimized maneuverability and stability for the Grumman X-29 which reportedly generated better control responses than comparable aircraft at up to 45 degree angle of attack. Forward swept wings configurations require the use of lightweight composite materials with a high yield strength in order to prevent twists and deformations. They are less common and often require the use of control surfaces and complex flight control systems to achieve optimum stability.
Research Question and Hypothesis
Despite stability and control challenges, aircraft configured with forward swept wings can achieve optimum flight performance characteristics and stability. How was aircraft design characteristics and enabling technologies optimized to achieve improved maneuverability and stability for the Grumman X-29 ? What are advantages and disadvantages of forward swept wings configurations?
Wing geometry, movable forward-mounted canards and a computerized fly-by-wire flight control systems significantly optimized maneuverability and stability for the Grumman X-29 which reportedly generated better control responses than comparable aircraft at up to 45 degree angle of attack. Airflow over a forward swept wings cause flow separation to start near the root which prevent the loss of aileron control at the tips. They generate higher magnitude of lift forces and produce higher lift coefficient and maximum lift coefficient. According to NASA, the reverse airflow also keeps the wing tips and ailerons from stalling at high angles of attack. This surprisingly renders more maneuverable aircraft configured with forward swept wings. They require the use of lightweight composite materials with a high yield strength in order to prevent structural divergence. They are less common and often requires the use of control surfaces and complex flight controls systems to achieve optimum stability.
Research Approach and Plan
The research study was primarily completed through a documentation analysis of existing research literature on the X-29, canards, and forward swept wings configurations as well as a mathematical analysis of equation defining aircraft performance characteristic and parameters. A basic case study was completed to evaluate performance characteristics of the X-29 against similar aircraft under similar conditions. Relevant research studies and textbooks were used for an analysis and evaluation of design goals, top level requirements, program constraints, and optimum design enablers. Through an evaluation and interpretation of advantages and disadvantages of forward swept wings, the X-29 design strengths and weaknesses were presented. Multiple databases and research tools such as the Embry-Riddle Hunt Library research tool, the AIAA publication and research database and the MIT Open courseware were use as a resource for the research. Microsoft Excel was used for basic data and statistical analysis.
Literature Review
The X-29 Grumman aircraft is a remarkable Jet Fighter configured with canards and forward swept wings. It is a remarkable aircraft that was designed to take advantage of forward swept wings characteristics such as a minimization of drag and an increase in lift (NASA, 2015). Multiple entities and researchers have studied the aircraft and its unique configurations and features. According to NASA, the reverse airflow also keeps the wing tips and ailerons from stalling at high angles of attack. This surprisingly renders more maneuverable aircraft configured with forward swept wings (NASA, 2015).
In the textbook titled : Introduction to Flight, Anderson highlights that Airflow over a forward swept wing cause flow separation to start near the root which prevent the loss of aileron control at the tips. They generate higher magnitude of lift forces and produce higher lift coefficient and maximum lift coefficient. Swept wings design also allows for a delay of drag divergence to much higher Mach numbers (Anderson, 2016).
Characteristics of the design configuration used for the X-29 Grumman is also discussed by Zhang G. et al. in their research study titled: Aerodynamic Characteristics of Canard-Forward Swept Wing Aircraft Configurations. They concluded that Compared with standard configurations, the use of canards can change the flow pattern of the main wing. Aerodynamic interference and mutual coupling between the canard and wing improve the lift characteristics of the FSW aircraft (Zhang G., 2013).
Stability and control characteristics of a forward mounted canard with forward swept wing configuration which characterizes the X-29 Grumman is discussed in the study titled: Stability and control of a three-surface, forward-swept wing configuration by Owens et al. They concluded that forward-swept wings have good stall characteristics and demonstrate a flat-top lift curve in the post-stall regime. They established that a canard with a canard-to-wing area ratio of 0.076 provide the best longitudinal stability. Owens et. al also conclude that when compared to a two-surface configuration with the same wing and empennage, the three-surface design which consists of an aft-mounted forward-swept wing, low horizontal tail location, and a forward-swept canard with a 7.6% canard-to-wing area ratio provided greater longitudinal control and increased range (Owens & Perkins, 1996).
The research study titled: Performance of a forward swept wing fighter utilizing thrust vectoring and reversing discusses adaptability of an Augmented Deflector Exhaust Nozzle to the X-29 Grumman. This tool led to a significant aircraft performance improvement. Miller reports 28 % decrease in takeoff ground roll, 4.5% decrease in approach speed, 7% decrease in landing ground roll, and 4% increase in instantaneous turn rate. The incorporation of a thrust reverser reportedly provides a 30% reduction in landing distance in addition to the tactical advantages that would be provided with in-flight deceleration (Miller, 1986).
In the research study titled: Propulsive aerodynamics of an advanced Nozzle/Forward swept wing aircraft configuration, Bowers concludes that changes in total lift, drag, and pitching moment coefficients are due to direct jet lift, jet induced aerodynamics, and the flap effect of the exhaust nozzle surface turned into the freestream flow. As Mach number increases, the contribution of the induced aerodynamic effects decreases, and the contribution of the exhaust nozzle flap effect increases. In other words, the interactions of the jet exhaust flow and the wing flow field decrease as Mach numbers increase (Bowers, 1981)
In the research study titled: CFD Analysis of the X-29 Inlet at High Angle of Attack, Tindell and Hill established through a CFD analysis that separation length was minimized by 40% at an angle of attack of 500 through the use of a slotted duct (Tindell & Hill, 1993).
In the research study titled: Numerical Study of Aerodynamic Characteristics of FSW Aircraft with Different Wing Positions Under Supersonic Condition, Lei, Zhao, and Wang demonstrate that the pitching moment and center of pressure coefficient increases as the distance between the FSW and the tail decreases (Lei, Zhao & Wang, 2016).
In the research study titled: The X-29 - a unique and innovative aerodynamic Concept, Frei and Moore demonstrate that the X-29 FSW configuration exhibits efficient stability and control characteristics and tremendous aerodynamics advantages when integrated with canards, flaperons and flaps (Frei & Moore, 1985).
In the publication titled: The Grumman X-29, Pace provide a thorough background, analysis, and evaluation of the X-29 Program. He established how the use of lightweight composite materials with high yield strength enabled the development of the aircraft by providing a solution for structural divergence (Pace, 1991).
In the publication titled: Grumman X-29, Gunston provide a background and analysis of the X-29 program. He concluded that the X-29 program solved aircraft stability issues through the use of a Fly-by-wire computerized control systems. The system essentially sent automated command to the forward mounted canards to correct responses based on measured flight conditions (Gunston, 1985).
In the publication titled: X-29 flight control system: Lessons learned, Bosworth demonstrated that the X-29 Fly-by-wire flight control system essentially constituted of a sub-system composed of a digital computer, sensors, and actuators. He further established how engineers integrated three redundant algorithms to prevent system failure (Bosworth, 1994).
Synthesis, Analysis, and Interpretation
A synthesis, analysis and interpretation of the X-29 aircraft program requires a system approach. The criteria for this evaluation shall include design objectives, aircraft requirements, program cost, development constraints, trade-offs, aircraft strength and weaknesses, and its value to current aircraft system design practices. The X-29 is often touted as a technology demonstrator that challenged the limits of aircraft design during its development and required the integration of new engineering and technological solutions (Pace, 1991). The Design of this operational forward swept wings (FSW) aircraft was rendered possible by the use of light but robust composite materials, a fly-by-wire computerized control systems and the use of forward mounted canards (Pace, 1991). FSW configurations are superior to conventional aircraft wings configurations. they offered 3 main advantages: higher maximum lift coefficient, lower bending moments and delayed stalls.
1. Design goals and Top Level Requirements
The objective of the X-29 program was to test and evaluate the feasibility of the forward swept wings (FSW) concept. The program had three main objectives. First, prove the benefits of the FSW configuration and its related technology. Second, confirm the airworthiness of the advanced technology demonstrator aircraft within an adequate angle of attack and speed and altitude envelope. Third, transfer program results to government and industry in a timely manner (Pace, 1991). The main requirement was to create an airworthy FSW vehicle capable of subsonic, transonic, and supersonic speed (Gunston, 1985). It is reported that NASA, DARPA, and the US Air Force aimed to evaluate theoretical advantages and characteristics of FSW. From a practical standpoint, the objective was to validate and verify whether FSW in fact offered optimum lift characteristics, improved maneuverability and aircraft control, and a more efficient flight at cruise speed. Engineers and manufacturers were also keen on evaluating whether FSW configurations significantly minimize drag.
The Grumman X-29 aircraft is defined by the following physical characteristics:
Table 1: Defined Physical characteristics of the Grumman X-29
The Grumman X-29 was equipped with a General Electric F-404- 400 engine. The aircraft maximum level speed reportedly exceeds Mach 1.8 (Gunston, 1985).
2. Cost, Materials, Technical, and Environmental Constraints
The Grumman X-29 program was defined as an experimental project. It was restricted to an 87 million budget for the production of 2 experimental aircraft. Given that the main objective was to prove the feasibility of forward swept wings aircraft, one of the most important constraints was the property of the materials used to build the aircraft wings. Prior researches and aircraft programs such as the JU-287 Bomber, the Cornelius XFG-1, and the Bell X1 had demonstrated the problem of structural divergence (Pace, 1991). Rotational forces generated by the wings cause twisting and bending motions that damage the wings through deformation. The magnitude of the twisting and bending forces increases proportionally with speed. High speed was unachievable with FSW aircraft through the use of conventional aircraft manufacturing materials like aluminum and titanium. An attempt to mitigate the effects of structural divergence through the use of conventional materials would have required aircraft wings that weight tons and rendered the aircraft unflyable (Pace 1991). Therefore, the Grumman X-29 was constrained to the use of composite materials. The use of advance composite materials wing covers was necessary to mitigate twisting due to structural divergence.
The Grumman X-29 program was unique as the objective was also to test for technical constraints and design and technology limitations. From a technical standpoint, airfoil shape sections and the flight control system represented the most significant challenges (Pace, 1991). In matter of fact, stability issues were a significant constraint due to the selected FSW configuration and especially the selected 3 points locations for the aircraft wings positions. Based on the basic principles of statics and dynamics, the aircraft system is not in equilibrium in flight as the wings are mounted away from the center of gravity. The net torque acting on the systems does not tend to zero because the extra weight is mounted in the aft section of the aircraft which creates an unbalanced system and a rotational motion where the forward section rises up (Hibbeler, 2006). When extrapolated to aerodynamics settings, this means that the nose of the aircraft will tend to oscillate and rise up and down as well as shift right and left across its center of gravity. This caused significant instability in flight and represented a tremendous design constraint for engineers on the X-29 Program.
3. Trades Made to Achieve Optimum Design
The achievement of optimum design required the integration of multiple components, sub-systems and enabling technologies. This included the use of Forward Swept Wings, thin supercritical wing sections, composite wing overs, variable camber devices, close-coupled variable-incidence canards foreplanes, strake flaps, 3 surface pitch control system, relaxed static stability system, nose strake and a digital flight by wire digital control system (Pace, 1991).
Figure 2: Depiction of components used by the Grumman X-29 to achieve optimum design. Retrieved from Pace, S. (1991). The Grumman X-29. Tab Books/McGraw-Hill, Inc.: Blue Ridge Summit, PA.
The first element that enabled optimum design was the use of composite wing covers characterized by a very high yield strength and a very low material weight. The use of composite minimized the effect of structural divergence and rendered feasible the development of a viable jet aircraft equipped with forward swept wings (Pace, 1991).
The second element that enabled optimum design is the use of forward mounted canards. Since the 3 points locations of the FSW created instability issues, forward mounted canards were added to the design configuration. The canards assist with pitch control and prevent root stall. Typical aircraft wing loading is also distributed across the forward swept wings and the canards (Owens & Perkins 1996).
The third element that enabled optimum design is the use of a fly-by-wire computerized control system. It essentially constituted of a sub-system composed of a digital computer, sensors, and actuators. Through the use of sensors, flight conditions such as speed, altitude, temperature, and pressure are measured and transmitted to the digital computer systems. The computer systems compute ideal flight and aircraft characteristics and communicate the data to the actuators who regulate the motion of the canards (Bosworth et al., 1994). Three redundant schemes were implemented to optimized ideal parameters calculation and prevent system failure. This resulted in up to 40 commands per second being executed by the actuators to achieve desired aircraft stability (Pace, 1991).
Other significant design elements include the use of a nose strake to prevent the aircraft nose from moving or oscillating right and left with respect to the aircraft center of gravity. Strake flaps were installed on the trailing edge as a secondary instrument for pitch control. The use of a three surface pitch control configuration allowed for optimum aircraft stability and maneuverability. It consisted of a sub-system of canards, flaperons and stake flaps. The configuration was instrumental in achieving a minimization of drag, pitch control, roll control, high light and controlling curvature changes (Pace 1991).
4. Final Design Effectiveness Evaluation - Strengths and Weaknesses
The Grumman X-29 aircraft is an extraordinary aircraft. It demonstrated capabilities superior to the conventional backward swept configuration while exhibiting only minor disadvantages due to its design and development constraints.
The Grumman X-29 is essentially characterized by the use of forward swept wings and forward mounted canards. FSW demonstrated improved efficiency compared to the conventional backward wings. They generate a higher maximum lift coefficient and minimized bending moments (Zhang et al., 2013). The FSW design allows for a delay of drag divergence to much higher Mach numbers. Forward swept wings delay stalls and at high angle of attacks, the unstalled wingtips enables the aircraft to maintain aileron control (Anderson, 2016). One of the most significant strength of the Grumman X-29 aircraft is its higher maneuverability. Its FSW and canard configuration yield higher maximum turn rates and renders the aircraft configuration ideal for air-to-air combat maneuvers. The use of a three surface pitch control configuration proved to be a significant solution to aircraft stability issues. In fact, the aircraft demonstrated improved stability at higher angle of attack. Other advantages include improved lift-to-drag ratio, better range at subsonic speed, lower minimum flight speed, greater aircraft range at subsonic speed and a minimization of take-off and landing distance (Gunston, 1985). The Grumman X-29 demonstrated better control and lift qualities in extreme maneuvers. The aircraft generated lower drag and produce a more efficient flight at cruise speed (Pace, 1991).
An evaluation of the weaknesses of the X-29 reveal that challenges with this aircraft pertains to its design and development constraints. Since forward swept wings are affected by structural divergence which leads to twisting and bending of the wings, the use of composite materials with a high yield strength is required (Gunston, 1985). Stability should not be highlighted as a disadvantage for this aircraft because the solutions implemented generated successful results. The forward mounted canard configuration, the use of a three surface pitch control configuration and the fly-by-wire computerized control systems actually led to improved aircraft stability and control (Pace, 1991). Nevertheless, the fly-by-wire concept was fairly complex and depended on a mathematical probability theory that indicated that the possibility of simultaneous failure of all 3 redundant algorithms used to maintain aircraft stability was very low (Pace, 1991). The hypothetical or solely theoretical scenario where all the fly-by-wire computer system algorithms simultaneously fail is a significant aircraft design and safety risk. Other disadvantages pertain to the difficulty of integrating stealth technology with forward swept wings and the potential redundancy of thrust vectoring capabilities with the FSW configuration.
5. Lessons Learn Applicable to Today's System Design
The Grumman X-29 aircraft was a significantly superior aircraft which technologies and design configurations were used to improve aircraft design and development principles. Although tremendous progress has been made in the development of aircraft design and technologies, the Grumman X-29 program provide valuable lessons that can be applied to today’s systems design. First, the use of composite materials to address design limitations and improve aircraft components characteristics is still beneficial to aircraft manufacturing. Second, the use of the forward swept wings configurations to increase aircraft speed and maneuverability still improves the performance characteristics of a significant number of aircraft being currently flown or developed. Third, the use of a digital computerized flight control system and flight control surfaces such as canards, strake flaps and nose strake to improve aircraft stability is still an invaluable practice in aircraft design today.
Summary and Conclusion
The Grumman X-29 aircraft is an experimental aircraft that is configured with forward swept wings and forward mounted canards. It is a technology demonstrator that is characterized by the use of a fly-by-wire computerized control system to optimize aircraft stability. The purpose of the program was to evaluate the forward swept wings (FSW) concept feasibility. The program had three main objectives. First, prove the benefits of the FSW configuration and its related technology. Second, confirm the airworthiness of the advanced technology demonstrator aircraft within an adequate angle of attack and speed and altitude envelope. Third, transfer program results to government and industry in a timely manner (Pace, 1991). Aircraft design and development efforts were most significantly constrained by the required use of light weight composites materials with a high yield strength. It provided an efficient solution to mitigate the effect of structural divergence by preventing twisting and bending motions that characteristically damaged FSW. Optimum design was achieved through the integration of multiple components, sub-systems and enabling technologies. It included the use of Forward Swept Wings, thin supercritical wing sections, composite wing overs, variable camber devices, close-coupled variable-incidence canards foreplanes, strake flaps, 3 surface pitch control system, relaxed static stability system, nose strake and a digital flight by wire digital control system.
The FSW configuration exhibited improved efficiency compared to the conventional backward wing. They generate a higher maximum lift coefficient and minimized bending moments (Zhang et al., 2013). The FSW design allows for a delay of drag divergence to much higher Mach numbers. FSW delay stalls and at high angle of attacks, the unstalled wingtips enables the aircraft to maintain aileron control (Anderson, 2016). One of the most significant strength of the Grumman X-29 aircraft is its higher maneuverability. Its FSW and canard configuration yield higher maximum turn rates and renders the aircraft configuration ideal for air-to-air combat maneuvers. The use of a three surface pitch control configuration was an efficient solution to aircraft stability issues. In fact, the aircraft demonstrated improved stability at higher angle of attack. The aircraft also demonstrated a multitude of improved capabilities which include improved lift-to-drag ratio, better range at subsonic speed, lower minimum flight speed, greater aircraft range at subsonic speed and a minimization of take-off and landing distance (Gunston, 1985). The Grumman X-29 demonstrated better control and lift qualities in extreme maneuvers. The aircraft generated lower drag and produce a more efficient flight at cruise speed (Pace, 1991). The Grumman X-29 demonstrated tremendous capabilities which were implemented on a plethora of newer aircraft programs. The true potential of this aircraft and its configuration has yet to be fulfilled. Engineers and manufacturers were drawn to new aircraft projects and the research and development of new technologies. FSW configurations were abandoned due to the difficulty of integrating stealth technology with forward swept wings and the potential redundancy of thrust vectoring capabilities with the FSW configurations.
Recommendation
The Grumman X-29 is an experimental aircraft which significantly contributed to the development of newer aircraft programs. Enabling technologies, design and performance lessons learned from the X-29 were implemented into newer fighter jets (Pace, 1991). Nevertheless, an analysis and evaluation of the X-29 indicates that the aircraft exhibited the most advanced performance characteristics among fighter aircraft at the time of its development. An integration of the X-29 aircraft concept with current design capabilities and enabling technologies will yield an advanced combat aircraft ideal for air-to-air combat applications.
As show by Table 1 above, maximizing the capabilities of the X-29 requires a fully configured combat aircraft designed for air-to-air combat. Stability and maneuverability of the Grumman X-29 shall be improved by implementing a variable FSW wing configuration. Engineers shall also evaluate opportunities for improving stability and control by mounting the Forward Swept Wings (FSW) much closer to the center of gravity of the aircraft. The three points location of the FSW shall support a fuselage and wings system in static equilibrium with the net torque equal to zero (Lei, Zhao & Wang, 2016). Flight control surfaces such as ailerons, slats, flaps, and strake flaps shall be used as secondary systems to improve performance and stability. Engineers shall also evaluate improvements to aircraft stability through a slight decrease in the FSW swept angle. The resulting change in maximum speed capabilities can be compensated by the use of newer engine capable of generating significantly more thrust. The Pratt & Whitney F135-PW-100 turbofan engine or the Pratt & Whitney F119-PW-100 turbofan engine are ideal for the propulsion system (US Air Force, 2014). These engines respectively power the F-35 Lightning II and the F-22 Raptor. The aircraft shall also be configured with a V-tail to minimize drag and improve aircraft maximum speed capabilities. The V-tail configuration has been proven feasible for advanced fighter aircraft. It is exhibited by the Northrop-McDonnell Douglas YF-23A ( US Air Force, 2015).
The aircraft performance capabilities can be optimized through a minimization of the overall aircraft system weight. This can be achieved through the use of advanced light weight composite materials with a high yield strength. The lower system weight directly optimize essential characteristics such as thrust to weight ratio, thrust required, lift coefficient, climb rate, wing loading, range, endurance, load factor, turn radius and turn rate. A lower turn radius and higher turn rate further increase maneuverability capability of the FSW configuration. In this case, the aircraft maximum speed can also be significantly increased by lowering the wing area (Anderson, 2016). An all composite fuselage and wing systems offer significant weight savings which shall be used for the integration of enabling technologies.
The fly-by-wire system can be adapted to other flight control surfaces such as ailerons, slats, flaps, and strake flaps. An alternate solution is to evaluate the possibility of equipping the aircraft with the newer fly-by-wireless systems which also offers significant weight savings (Studor, 2007). The aircraft shall be equipped with the most advanced technologies and weapons systems seen on the F-35 Lightning II and the F22 Raptor. Despite the FSW configuration, a redundant thrust vectoring system shall be incorporated into the aircraft systems. This configuration is exhibited by the Russian Sukhoi Su-47. It optimizes aircraft maneuverability (Schwede & Brookes, 2015). Enabling technologies shall include advanced vehicle control, maneuver control and trajectory correction control systems, advanced navigation and positioning features, innovative obstacle avoidance algorithms, vehicle monitoring and structural health monitoring sub-systems. The aircraft shall also be equipped with advanced sensors and radars systems (Schwede & Brookes, 2015). This shall include radar warning receivers, missile approach warning tool, active electronically scanned array, cognitive radio, electro-optical sensors, infrared cameras, cooled and uncooled infrared detectors (Saab, n.d.). These technologies are currently exhibited by the JAS 39 Gripen and the Dassault Rafale. Finally, the use of composite presents an opportunity to address the challenges of implementing stealth technology with FSW aircraft. The aircraft shall be equipped with an all-weather stealth system and technology.
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