A mathematical model of a tilt-wing aircraft for piloted simulation

A mathematical model of a tilt-wing aircraft that was used in a piloted, six-degree-of-freedom flight simulation application is described. Two types of control systems developed for the math model are discussed: a conventional, programmed-flap wing-tilt control system and a geared-flap wing-tilt control system. The primary objective was to develop the capability to study tilt-wing aircraft. Experienced Tilt-wing pilots subjectively evaluated the model using programmed-flap control to assess the quality of the simulation. The math model was then applied to study geared-flap control to investigate the possibility of eliminating the need for auxilary pitch-control devices (such as the horizontal tail rotor or tail jet used in earlier tilt-wing designs). This investigation was performed in the moving-base simulation environment, and the vehicle responses with programmed-flap and geared-flap control were compared. The results of the evaluation of the math model are discussed

Control of a human-powered helicopter in hover

The study of a control system for the Da Vinci 2 human-powered helicopter in hovering flight is documented. This helicopter has two very large, slowly rotating rotor blades and is considered to be unstable in hover. The control system is designed to introduce stability in hover by maintaining level rotors through the use of rotor tip mounted control surfaces. A five degree of freedom kinematic model was developed to study this control system and is documented. Results of this study show that the unaugmented configuration is unstable due to the large Lock Number, and the augmented configuration is stable. The role of NASA in this study included the development and analysis of the kinematic model and control laws. Both analytical and numerical techniques were used

Rotor and control system loads analysis of the XV-15 with the advanced technology blades

An analysis of the rotor and control system loads of the XV-15 with the Advanced Technology Blades (XV-15/ATB) was conducted to study the effects of modifications designed to alleviate high collective actuator loads encountered during initial flight tests. Rotor loads predictions were correlated with flight data to establish accuracies of the methodology used in the analysis. Control system loads predictions were then examined and were also correlated with flight data. The results showed a significant reduction in 3/rev collective actuator loads of the XV-15/ATB when the control system stiffness was increased and the rotor blade chord balance and tip twist were modified

Helicopter Airborne Laser Positioning System (HALPS)

The theory of operation, configuration, laboratory, and ground test results obtained with a helicopter airborne laser positioning system developed by Princeton University is presented. Unfortunately, due to time constraints, flight data could not be completed for presentation at this time. The system measures the relative position between two aircraft in three dimensions using two orthogonal fan-shaped laser beams sweeping across an array of four detectors. Specifically, the system calculates the relative range, elevation, and azimuth between an observation aircraft and a test helicopter with a high degree of accuracy. The detector array provides a wide field of view in the presence of solar interference due to compound parabolic concentrators and spectral filtering of the detector pulses. The detected pulses and their associated time delays are processed by the electronics and are sent as position errors to the helicopter pilot who repositions the aircraft as part of the closed loop system. Accuracies obtained in the laboratory at a range of 80 ft in the absence of sunlight were + or - 1 deg in elevation; +0.5 to -1.5 deg in azimuth; +0.5 to -1.0 ft in range; while elevation varied from 0 to +28 deg and the azimuth varied from 0 to + or - 45 deg. Accuracies in sunlight were approximately 40 deg (+ or - 20 deg) in direct sunlight

A Mission-Adaptive Variable Camber Flap Control System to Optimize High Lift and Cruise Lift-to-Drag Ratios of Future N+3 Transport Aircraft

Boeing and NASA are conducting a joint study program to design a wing flap system that will provide mission-adaptive lift and drag performance for future transport aircraft having light-weight, flexible wings. This Variable Camber Continuous Trailing Edge Flap (VCCTEF) system offers a lighter-weight lift control system having two performance objectives: (1) an efficient high lift capability for take-off and landing, and (2) reduction in cruise drag through control of the twist shape of the flexible wing. This control system during cruise will command varying flap settings along the span of the wing in order to establish an optimum wing twist for the current gross weight and cruise flight condition, and continue to change the wing twist as the aircraft changes gross weight and cruise conditions for each mission segment. Design weight of the flap control system is being minimized through use of light-weight shape memory alloy (SMA) actuation augmented with electric actuators. The VCCTEF program is developing better lift and drag performance of flexible wing transports with the further benefits of lighter-weight actuation and less drag using the variable camber shape of the flap

Aerodynamic Analysis of the Truss-Braced Wing Aircraft Using Vortex-Lattice Superposition Approach

The SUGAR Truss-BracedWing (TBW) aircraft concept is a Boeing-developed N+3 aircraft configuration funded by NASA ARMD FixedWing Project. This future generation transport aircraft concept is designed to be aerodynamically efficient by employing a high aspect ratio wing design. The aspect ratio of the TBW is on the order of 14 which is significantly greater than those of current generation transport aircraft. This paper presents a recent aerodynamic analysis of the TBW aircraft using a conceptual vortex-lattice aerodynamic tool VORLAX and an aerodynamic superposition approach. Based on the underlying linear potential flow theory, the principle of aerodynamic superposition is leveraged to deal with the complex aerodynamic configuration of the TBW. By decomposing the full configuration of the TBW into individual aerodynamic lifting components, the total aerodynamic characteristics of the full configuration can be estimated from the contributions of the individual components. The aerodynamic superposition approach shows excellent agreement with CFD results computed by FUN3D, USM3D, and STAR-CCM+

Mobile Mapping and its Potential for Faculty Collaboration and Undergraduate Student Learning

Undergraduate research is a high impact practice for student learning, but the key is often to match projects with tools that build students’ skills as they learn about a topic. Digital tools now profligate to the point that they are almost overwhelming to the student and teacher alike. These tools, coupled with computing have forged an entirely new field: digital humanities. Our manuscript discusses how one easy to use, student friendly digital tool—ARCGIS’s mobile app, Collector—is used in collaborative undergraduate research. The tool’s usefulness stems from its potential to contribute to the relationship between the discourse on digital humanities with its actual practice in the classroom. The Collector App encourages undergraduate researchers to go beyond the confines of the classroom and into the field to conduct research with one of their favorite tools, their smartphone. The Collector App allows past-present-and future classes of students to intermingle in a digital space that is devoted to creating knowledge for public use. The easy-to-use digital tool facilitates undergraduates in the Humanities and other disciplines to become cognizant of the world immediately around them in a new way while also equipping them with a technical skill that may be applied in other courses as well as in future employment scenarios. In short, the Collector App serves as a place where applied research and the scholarship of discovery intersect. As such, the Collector App contributes to the expansion of the digital humanities into undergraduate education. We present as evidence several different collaborative digital undergraduate projects that span classes and semesters and all involve primary field research through Collector. The Collector-based research projects have encouraged students to build skills while contributing to knowledge in new ways.La recherche de premier cycle est une pratique à fort impact sur l'apprentissage des étudiants, mais la clé est souvent de trouver des outils qui renforcent les compétences des étudiants tout en apprenant sur un sujet donné. Les outils numériques sont maintenant si présents qu'ils sont presque écrasants tant pour les élèves que pour les enseignants. Ces outils, associés à l'informatique, ont forgé un tout nouveau domaine : les sciences humaines numériques. Notre manuscrit explique la façon dont un outil numérique facile à utiliser et convivial pour les étudiants — l'application mobile d'ARCGIS, Collector — est utilisé dans la recherche collaborative dans le premier cycle universitaire. L'utilité de l'outil découle de son potentiel à contribuer à la relation entre le discours sur les sciences humaines numériques et sa pratique réelle en classe. Le Collector App encourage les chercheurs de premier cycle à sortir des limites de la salle de classe et à se rendre sur le terrain pour mener des recherches avec l'un de leurs outils préférés, leur téléphone portable mobile. L'application Collector permet aux anciennes et futures classes d'élèves de se mêler dans un espace numérique dédié à la création de connaissances à usage public. Cet outil numérique facile à utiliser permet aux étudiants de premier cycle en sciences humaines et dans d'autres disciplines de se familiariser avec le monde qui les entoure immédiatement et de façon nouvelle tout en acquérant une compétence technique qui pourra être utilisée dans d'autres cours ainsi que dans de futurs scénarios professionnels. En résumé, l'application Collector sert de lieu d'intersection entre la recherche appliquée et la découverte scientifique. À ce titre, l'application Collector App contribue à l'expansion des sciences humaines numériques dans l'enseignement de premier cycle. Nous présentons comme preuve plusieurs projets de collaboration de premier cycle en numérique qui s'étendent sur plusieurs classes et semestres et qui impliquent tout une recherche primaire sur le terrain par le biais de Collector