New Wing Design Exponentially Increases Total Aircraft Efficiency
Adverse yaw, present in current aircraft design, is the adverse horizontal movement around a vertical axis of an aircraft; the yaw opposes the direction of a turn. As an aircraft turns, differential drag of the left and right wings while banking contributes to aircraft yaw. Proverse yaw—yawing in the same direction as a turn—would optimize aircraft performance. Initial results from flight experiments at Armstrong demonstrated that this wing design unequivocally established proverse yaw. This wing design further reduces drag due to lift at the same time. <strong>How It Works</strong> The Armstrong team (supported by a large contingent of NASA Aeronautics Academy interns) built upon the 1933 research of the German engineer Ludwig Prandtl to design and validate a scale model of a non-elliptical loaded wing that reduces drag and increases efficiency. The key to the innovation is reducing the drag of the wing through use of an alternative bell-shaped spanload, as opposed to the conventional elliptical spanload. To achieve the bell spanload, designers used a sharply tapered wing, with 12 percent less wing area than the comparable elliptical spanload wing. The new wing has 22 percent more span and 11 percent less area, resulting in an immediate 12 percent drag reduction. Furthermore, using twist to achieve the bell spanload produces induced thrust at the wing tips, and this forward thrust increases when lift is increased at the wingtips for roll control. The result is that the aircraft rolls and yaws in the same direction as a turn, eliminating the need for a vertical tail. When combined with a blended-wing body, this approach maximizes aerodynamic performance, minimizes weight, and optimizes flight control. <strong>Why It Is Better</strong> Conventional aircraft make use of elliptical loaded wings to minimize drag. However, achieving aircraft stability and control in conventional elliptical wings produces a strong adverse yaw component in roll control (i.e., the aircraft will yaw the opposite direction with application of roll control). Therefore, a vertical tail or some other method of direct yaw control is required, such as split elevons for use as drag rudders. The use of elliptical wings also results in a suboptimal amount of structure to carry the integrated wing bending moment. Adopting the bell-shaped spanload change results in an immediate 12 percent drag reduction. In addition, optimization of the overall aircraft configuration is projected to achieve additional significant overall performance increases.
electrical and electronics
Analog Signal Correlating
Each of two analog signals (channels A and B) is converted to a digital bit stream by phase correcting it and comparing it to an average of itself at a sampling clock rate f. The hard-limited conversions of A and B are bitwise compared to measure the level of similarity between the two by the OBDC. This similarity measurement X is equal to the maximum possible Hamming distance (N bits in disagreement) minus the measured number of bits in disagreement. The OBDC functions are embedded into a field programmable gate array (FPGA). The OBDC is made up of two shift registers containing the current sample values (of length N) from each of the two input channels (A and B). During each sample clock, a new sample from each A and B input is clocked into the input linear shift register for each respective channel; this input shifts the current values in the linear shift register. Once the inputs have been clocked in, the correlation routine can start. Once the correlation value has been calculated, this result is forwarded to compare with the max correlation value register. If the X value is greater than the current max correlation value, then the max correlation value becomes X, and the shift counter register is latched and put into the best correlation index register, providing the index of the current best correlation. This index is the number of sample clock periods difference between the two input signals and thus, for sample clock rate f, indicates the delay between the signals A and B. This is an early-stage technology requiring additional development. Glenn welcomes co-development opportunities.
Spatial Standard Observer (SSO)
The Spatial Standard Observer (SSO) provides a tool that allows measurement of the visibility of an element, or visual discriminability of two elements. The device may be used whenever it is necessary to measure or specify visibility or visual intensity. The SSO is based on a model of human vision, and has been calibrated by an extensive set of human test data. The SSO operates on a digital image or a pair of digital images. It computes a numerical measure of the perceptual strength of the single image, or of the visible difference between the two images. The visibility measurements are provided in units of Just Noticeable Differences (JND), a standard measure of perceptual intensity. A target that is just visible has a measure of 1 JND. The SSO will be useful in a wide variety of applications, most notably in the inspection of displays during the manufacturing process. It is also useful in for evaluating vision from unpiloted aerial vehicles (UAV) predicting visibility of UAVs from other aircraft, from the control tower of aircraft on runways, measuring visibility of damage to aircraft and to the shuttle orbiter, evaluation of legibility of text, icons or symbols in a graphical user interface, specification of camera and display resolution, inspection of displays during the manufacturing process, estimation of the quality of compressed digital video, and predicting outcomes of corrective laser eye surgery.
Variable Geometry Aircraft Wing Supported By Struts and/or Trusses
This innovation utilizes a strut/truss-braced oblique variable-sweep wing mounted on a constant cross-section geometry fuselage. The combination of the strut/truss-bracing with the oblique wing greatly reduces the structural and weight penalties previously associated with unbraced oblique wing configurations while maintaining the oblique wings improved aerodynamic performance. Strut/truss bracing helps to further reduce the wing weight, and can be used to automatically align wing-mounted engines with the oncoming flow. The synergistic combination of these design elements provides the aircraft with a wide and efficient cruise speed range when the wing is at intermediate sweep positions, and superior low speed performance when the wing is unswept. The wing could remain aligned during taxiing, reducing the chance of collisions with other taxiing aircraft. This wide speed envelope provides future air traffic systems with additional flexibility when scheduling efficient arrivals and departures. The improved climb performance of the straight wing reduces the neighborhood noise footprint of the aircraft as it departs the airport. Efficient aircraft designs are increasingly desired in order to support the continued growth of the air transportation industry. Continued expansion of this vital mode of transportation is threatened by ever-increasing challenges in emissions, noise, and fuel efficiency.
Green aviation - improved aerodynamic efficiency and less fuel burn
Currently, as fuel is burned, wing loading is reduced, thereby causing the wing shape to bend and twist. This wing-shape change causes the wings to be less aerodynamically efficient. This problem can be further exacerbated by modern high-aspect flexible wing design. Aircraft designers typically address the fuel efficiency goal by reducing aircraft weights, improving propulsion efficiency, and/or improving the aerodynamics of aircraft wings passively. In so doing, the potential drag penalty due to changes in the wing shapes still exists at off-design conditions. The unique or novel features of the new concepts are: 1. Variable camber flap provides the same lift capability for lower drag as compared to a conventional flap. The variable camber trailing edge flap (or leading edge slat) comprises multiple chord-wise segments (three or more) to form a cambered flap surface, and multiple span-wise segments to form a continuous trailing edge (or leading edge) curve with no gaps which could be prescribed by a mathematical function or the equivalent with boundary conditions enforced at the end points to minimize tip vortices 2. Continuous trailing edge flap (or leading edge slat) provides a continuously curved trailing edge (or leading edge) with no gaps to minimize vortices that can lead to an increase in drag. 3. The active wing-shaping control method utilizes the novel flap (or slat) concept described herein to change a wing shape to improve aerodynamic efficiency by optimizing span-wise aerodynamics. 4. An aeroelastic wing shaping method for analyzing wing deflection shape under aerodynamic loading is used in a wing-control algorithm to compute a desired command for the flap-actuation system to drive the present flap (or slat) system to the correct position for wing shaping.
Aeroelastic Wing Shaping
Distributed propulsion and lightweight flexible structures on air vehicles pose a significant opportunity to improve mission performance while meeting next generation requirements including reduced fuel burn, lower emissions, and enhanced takeoff and landing performance. Flexible wing-shaping aircraft using distributed propulsion enable the ability to achieve improved aerodynamic efficiency while maintaining aeroelastic stability. Wing shaping concepts using distributed propulsion leverage the ability to introduce forces/ moments into the wing structure to affect the wing aerodynamics. This can be performed throughout the flight envelope to alter wing twist, hence local angle of attack, as the wing loading changes with air vehicle weight during cruise. Thrust-induced lift can be achieved by distributed propulsion for enhanced lift during take-off and landing. For a highly flexible wing structure, this concept could achieve a 4% improvement in lift-to-drag ratio, hence reduced fuel burn, as compared to a conventional stiff wing. This benefit is attributed to a reduction in lift-induced drag throughout the flight envelope by actively shaping the spanwise lift distribution using distributed propulsion. Vertical tail size could be reduced by utilizing differential thrust flight-propulsion control. This will result in weight reduction to achieve further fuel savings. Aeroelastic stability is addressed in the design process to meet flutter clearance requirements by proper placement of the propulsion units. This technology enables synergistic interactions between lightweight materials, propulsion, flight control, and active aeroelastic wing shaping control for reducing the environmental impact of future air vehicles.
Aircraft Active Pylon Noise Control System
For use on aircraft, the air intake would be on the pylon at an aerodynamically advantageous location. The delivery system would consist of pipes, a pump or pressure regulator and a plenum chamber. The air is piped through the internal pylon structure in pipes by a pump and to the plenum chamber. The injection site for the most common embodiments would be the shelf of the pylon (adjacent to the core nozzle flow) and the trailing edge of the pylon. The objective of the injection is to alter the trajectory of the core nozzle flow thereby impacting how the core and fan streams mix and the overall trajectory of the core and fan streams together. The injection site on the trailing edge has the objective of minimizing the wake of the pylon by injecting higher pressure and velocity air through the active aircraft pylon trailing edge injector. At cruise conditions, injection from the pylon trailing edge can also reduce the drag contribution of the pylon to the total aircraft drag.
Improved Ground Collision Avoidance System
This critical safety tool can be used for a wider variety of aircraft, including general aviation, helicopters, and unmanned aerial vehicles (UAVs) while also improving performance in the fighter aircraft currently using this type of system. <strong>Demonstrations/Testing</strong> This improved approach to ground collision avoidance has been demonstrated on both small UAVs and a Cirrus SR22 while running the technology on a mobile device. These tests were performed to the prove feasibility of the app-based implementation of this technology. The testing also characterized the flight dynamics of the avoidance maneuvers for each platform, evaluated collision avoidance protection, and analyzed nuisance potential (i.e., the tendency to issue false warnings when the pilot does not consider ground impact to be imminent). <strong>Armstrong's Work Toward an Automated Collision Avoidance System</strong> Controlled flight into terrain (CFIT) remains a leading cause of fatalities in aviation, resulting in roughly 100 deaths each year in the United States alone. Although warning systems have virtually eliminated CFIT for large commercial air carriers, the problem still remains for fighter aircraft, helicopters, and GAA. Innovations developed at NASAs Armstrong Flight Research Center are laying the foundation for a collision avoidance system that would automatically take control of an aircraft that is in danger of crashing into the ground and fly it—and the people inside—to safety. The technology relies on a navigation system to position the aircraft over a digital terrain elevation data base, algorithms to determine the potential and imminence of a collision, and an autopilot to avoid the potential collision. The system is designed not only to provide nuisance-free warnings to the pilot but also to take over when a pilot is disoriented or unable to control the aircraft. The payoff from implementing the system, designed to operate with minimal modifications on a variety of aircraft, including military jets, UAVs, and GAA, could be billions of dollars and hundreds of lives and aircraft saved. Furthermore, the technology has the potential to be applied beyond aviation and could be adapted for use in any vehicle that has to avoid a collision threat, including aerospace satellites, automobiles, scientific research vehicles, and marine charting systems.
High-Speed Smart Camera Detects Supersonic Inlet Shocks
In order for the camera to detect invisible air shocks in an aircraft engine's intake, a fine sheet of laser light is first projected through the airflow. The light is refracted in the densest part of the airflow (the location of the shock), which creates a dark spot that shows up as a dip or negative peak in the pixel intensity profile of the image. The smart camera uses this information to identify a negative going edge and a positive going edge, which is expressed as numeric pixel values within the linear array. Data is output from the circuit as an analog signal or digitally by an onboard microcontroller using a parallel digital bus or a serial interface such as the controller area network (CAN bus), Ethernet, RS-232/485 or USB. Unlike conventional edge detection systems, which rely on both a high-speed camera and a bulky computer or digital signal processor, this innovation uses an analog technique to process images. Its simple, sleek design consists of three basic parts: a linear image sensor, an analog signal processing circuit, and a digital circuit. The result is a smaller, more reliable technology with increased processing frame rates. The design can easily be tailored to the end use, and can be reconfigured to respond to positive and/or negative going edges. Furthermore, the threshold sensitivity can be varied and algorithmically set, making it well suited for a number of other terrestrial applications from transportation to manufacturing.
Foot Pedal Controller
The Foot Pedal Controller enables an operator of a spacecraft, aircraft, or watercraft, or a simulation of one in a video game, to control all translational and rotational movement using two foot pedals. This novel technology allows control across all six degrees of freedom, unlike any technology on the market. The components of the technology are a support structure, a left foot pedal, a right foot pedal, and supporting electronics. The Foot Pedal Controller is intuitive, easy to learn, and has ergonomic features that accommodate and stabilize the operator's feet. A working prototype is available to demonstrate key technology features to potential licensees. The Foot Pedal Controller technology could be used in designs for the flight deck of the future, video game controls, drone operations and flight simulators. This technology can be useful in any application where it is preferred or desirable to use the feet to control motion rather than using the hands. A potential market could be foot control of equipment by people with arm or hand disabilities. A unique aspect of the innovation is the consideration of natural foot mechanics in the design and placement of the sensors and actuators to reduce operator fatigue. The axes of rotation of the Controller align with the joints of the foot so the foot moves naturally to control the movement of the craft. NASA seeks collaborations with companies interested in licensing and partnering to further develop and commercialize the technology.