Browse Topic: Flight dynamics

Items (303)

Basic Science and Art of Aircraft Wreckage Reconstruction

R-48004/23/2025

Basic Science and Art of Aircraft Wreckage Reconstruction is a unique title which addresses important aspects of investigating crashes, who does this kind of work, and how a healthy attitude and open mind are required to properly perform investigations. It also discusses what to expect from the on-scene part of the investigation, and the fundamental approaches to common types of wreckage reconstruction. Written by Don Knutson, a veteran of this industry, Basic Science and Art of Aircraft Wreckage Reconstruction is intended for the practitioner, student, or those who are simply curious about how aircraft wreckage is reconstructed. Full references are provided in the various chapters for additional reading and research. Many examples of aircraft crash scenarios and circumstances are presented in a "generic" form but relate to actual investigations, which should prove as a useful investigative resource whether you are an apprentice or an experience professional with a government aviation

Knutson, Donald F.

Longitudinal Air-Breathing Hypersonic Vehicle Nonlinear Dynamic Simulation with Different Control Inputs

01-17-02-0015

03/04/2024

The air-breathing hypersonic vehicle (AHV) holds the potential to revolutionize global travel, enabling rapid transportation to low-Earth orbit and even space within the next few decades. This study focuses on investigating the nonlinear dynamic simulation, trim, and stability analysis of a three-degrees-of-freedom (3DOF) longitudinal model of a generic AHV for variable control surface deflection,and. A simulation is developed to analyze the burstiness of the AHV’s nonlinear longitudinal behavior, considering the complete flight envelope across a wide range of Mach numbers, from= 0 to 24, for selected stable. The presented simulation assesses trim analysis and explores the dynamic stability of the AHV through its flight envelope and bifurcation method analysis is carried out to gain insight and validate the dynamic stability using eigen value approach.

Singh, Ritesh, Prakash, Om, Joshi, Sudhir, Sharma, Rakesh Chandmal

An Aerodynamic Equation of State—Part II: Applications to Flapping Flight

01-17-01-0002

04/19/2023

Part I introduced the aerodynamic equation of state. This Part II introduces the aerodynamic equation of state for lift and induced drag of flapping wings and applies it to a hovering and forward-flying bumblebee and a mosquito. Two- and three-dimensional graphical representations of the state space are introduced and explored for engineered subsonic flyers, biological fliers, and sports balls.

Burgers, Phillip

Instrumentation for Fabrication and Testing of High-Speed Single-Rotor and Compound-Rotor Systems

20AERP10_0710/01/2020

Precision data acquisition is required to generate a comprehensive set of measurements of the blade surface pressures, pitch link loads, hub loads, rotor wakes and performance of high-speed single-rotor and compound-rotor systems to support the development of next-generation rotorcraft. Army Research Office, Research Triangle Park, North Carolina Precision data acquisition is required to generate a comprehensive set of measurements of the blade surface pressures, pitch link loads, hub loads, rotor wakes and performance of high-speed single-rotor and compound-rotor systems to support the development of next-generation rotorcraft, such as envisioned in the Joint Multi-Role (JMR) rotorcraft program. These data are crucial to validate advanced CFD tools, as well as gain improved understanding of the fundamental physics in high advance ratio flight conditions. The research program at the Alfred Gessow Rotorcraft Center (AGRC) is built around four interrelated thrust areas, namely

Instrumentation for Fabrication and Testing of High-Speed Single-Rotor and Compound-Rotor Systems

TBMG-3788010/01/2020

Flight Optimization Model on Global and Interval Ranges for Conceptual Studies of MEA Systems

2019-01-190609/16/2019

In development of more electric aircraft applications, it is important to discuss aircraft energy management on various level of aircraft operation. This paper presents a computationally efficient optimization model for evaluating flight efficiency on global and interval flight ranges. The model is described as an optimal control problem with an objective functional subjected to state condition and control input constraints along a flight path range. A flight model consists of aircraft point-mass equations of motion including engine and aerodynamic models. The engine model generates the engine thrust and fuel consumption rate for operation condition and the aerodynamic model generates the drag force and lift force of an aircraft for flight conditions. These models is identified by data taken from a published literature as an example. First, approximate optimization process is performed for climb, cruise, decent and approach as each interval range path. Next, optimization for global

Shibuya, Yotsugi, Oyori, Hitoshi, Sugawara, Hirotaka, Seki, Naoki

Computational Analysis of Flap Camber and Ground Clearance in Double-Element Inverted Airfoils

2019-01-506506/11/2019

Drag and lift are the primary aerodynamic forces experienced by automobiles. In competitive automotive racing, the design of inverted wings has been the subject of much research aimed at improving the performance of vehicles. In this direction, the aerodynamic impact of change in maximum camber of the flap element and ground effect in a double-element inverted airfoil was studied. The National Advisory Committee for Aeronautics (NACA) 4412 airfoil was taken as the constant main element. The camber of the flap element was varied from 0% to 9%, while ground clearance was varied from 0.1c to 1.0c. A two-dimensional (2D) Computational Fluid Dynamics (CFD) study was performed using the realizable k-ε turbulence model in ANSYS Fluent 18.2 to analyze the aerodynamic characteristics of the airfoil. Parameters such as drag coefficient, lift coefficient, pressure distribution, and wake flow field were investigated to present the optimum airfoil configuration for high downforce and low drag. It

Kashyap, Vishesh, Bhattacharjee, Sourajit

Facing the Challenges of Supercooled Large Droplet Icing: Results of a Flight Test Based Joint DLR-Embraer Research Project

2019-01-198806/10/2019

Today’s airplanes are well equipped to cope with most common icing conditions. However, some atmospheric conditions consisting of supercooled large droplets (SLD) have been identified as cause of severe accidents over the last decades as existing countermeasures even on modern aircraft are not necessarily effective against SLD-ice. In 2014, the new Appendix O to the certification regulations (FAR Part 25 / CS-25) had been issued to guarantee the safe operation of future airplane when encountering SLD conditions. But as the SLD topic is quite new for the majority of aircraft manufacturers and research institutes in a same way, DLR (German Aerospace Center) and Embraer established a joint research cooperation in 2012 to obtain a better understanding of the distinct influences of SLD-ice shapes on aircraft characteristics and to evaluate proper ways for future airplane certification under App. O. Furthermore, one additional scientific goal of the cooperation was to develop and test new

Deiler, Christoph, Ohme, Per, Raab, Christian, Mendonca, Celso, Silva, Daniel

Landing Response Analysis on High-Performance Aircraft ^* Using Estimated Touchdown States

01-12-01-000104/08/2019

A novel use of state estimation methods as initial input for a landing response analysis is proposed in this work. Six degrees of freedom (DOF) non-linear landing response model is conceived by considering longitudinal dynamics of aircraft as a rigid body with heave-and-pitch motions coupled onto a bicycle landing gear† arrangement. The DOF for each landing gear consist of vertical and longitudinal motions of un-sprung mass, considering strut bending flexibility. The measurement data for state estimation is obtained for three landing cases using non-linear flight mechanics model interfaced with pilot-in-loop simulation. State estimation methods such as Upper Diagonal Adaptive Extended Kalman Filter (UD-AEKF) with fuzzy-based adaptive tuning and Un-scented Kalman Filter (UKF) were adapted for landing maneuver problem. On the basis of estimation error metrics, aircraft state from UKF is considered during onset of touchdown. These estimated states are used as an initial condition for the

Suresh, P.S., Sura, Niranjan Kumar, Shankar, K.

Landing Gear Stability

AIR4894 (Current)10/18/2017

This SAE Aerospace Information Report (AIR) discusses the nature of landing gear stability, describes many common landing gear stability problems, and suggests approaches and methods for solving or avoiding them.

A-5B Gears, Struts and Couplings Committee

A New VTOL Propelled Wing for Flying Cars: Critical Bibliographic Analysis

2017-01-214409/19/2017

This paper is a preliminary step in the direction of the definition of a radically new wing concept that has been conceived to maximize the lift even at low speeds. It is expected to equip new aerial vehicle concepts that aim to compete against helicopters and tilt rotors. They aim achieving very good performance at very low speed (5 to 30 m/s) by mean of an innovative concept of morphing ducted-fan propelled wing that has been designed to maximize the lift force. This paper presents an effective bibliographic analysis of the problem that is a preliminary necessary step in the direction of the preliminary design of the wing. A preliminary CFD evaluation allows demonstrating that the claimed results are in line with the initial expectations. According to the CFD, results it has been produced a preliminary energetic evaluation of the vehicle in a flying car configuration by EMIPS method. Even if the results are still preliminary, they allow evidencing a good energy efficiency of the

Trancossi, Michele, Hussain, Mohammad, Shivesh, Sharma, Pascoa, Jose

Improved Ground Collision Avoidance System (iGCAS)

TBMG-2600412/01/2016

Researchers at NASA’s Armstrong Flight Research Center have dramatically improved upon existing ground collision avoidance technology for aircraft. NASA’s system leverages leading-edge fighter safety technology, adapting it to civil aviation use as an advanced warning system. It offers higher fidelity terrain mapping, enhanced vehicle performance modeling, multidirectional avoidance techniques, more efficient data-handling methods, and user-friendly warning systems. The algorithms have been incorporated into an app for tablet/handheld mobile devices that can be used by pilots in the cockpit, enabling significantly safer general aviation. This will enable pilots to have access to this lifesaving safety tool regardless of what type of aircraft they are flying. The system also can be incorporated into electronic flight bags (EFBs) and/or aircraft avionics systems.

Applying the Dynamic Inertia Measurement Method to Full-Scale Aerospace Vehicles

TBMG-2549610/01/2016

Researchers at NASA’s Armstrong Flight Research Center have been interested in using the Dynamic Inertia Measurement (DIM) method on full-scale aerospace test vehicles, given its advantages over traditional methods for determining the mass properties of such vehicles. Developed at the University of Cincinnati, the DIM method uses a ground vibration test setup to determine mass properties using data from frequency-response functions. The method has been successfully tested on a number of small-scale test articles — including automobile brake rotors, steel blocks, and custom fixtures — but until now, has had limited success being tested in larger applications. Armstrong’s recent efforts, in conjunction with ground vibration tests, represent a step forward in applying the DIM method successfully to full-scale aerospace vehicles.

Aerodynamic Analysis of the Elytron 2S Experimental Tiltwing Aircraft

2016-01-200809/20/2016

The Elytron 2S is a prototype aircraft concept to allow VTOL capabilities together with fixed wing aircraft performance. It has a box wing design with a centrally mounted tilt-wing supporting two rotors. This paper explores the aerodynamic characteristics of the aircraft using computational fluid dynamics in hover and low speed forward flight, as well as analyzing the unique control system in place for hover. The results are then used to build an input set for NASA Design and Analysis if Rotorcraft software allowing trim and flight stability and control estimations to be made with SIMPLI-FLYD.

Grima, Alexander, Theodore, Colin, Garrow, Oliver, Lawrence, Ben, Persson, Linnea

Trajectory Optimization of a Dynamic Soaring UAV

2016-01-198009/20/2016

This paper studies admissible state trajectories for an unmanned aerial vehicle(UAV) by performing dynamic soaring technique in the wind gradient. An optimization problem is formulated by employing direct optimal piece wise control. A 3-DOF point mass model system dynamics of UAV is considered. The bank angle and lift co-efficient are identified as control variables. A UAV of mass 5.44kg is considered for this study. Performance measures considered are maximization of specific energy and maximization of specific energy rate extracted by the vehicle, and minimization of the control effort. The effects of linear and parabolic wind gradient on maximizing the specific energy of an autonomous dynamic soaring UAV is also studied and minimum linear gradient required is found. The loop radius of the loiter pattern is maximized for applications like surveillance and patrolling of a localized area along with energy maximization as objective function. Genetic algorithm is used for optimization

Rao, Syama M., M, Dineshkumar

Design and Development of Autonomous Amphibious Unmanned Aerial Vehicle and UAV Mountable Water Sampling Devices for Water Based Applications

2016-01-200409/20/2016

In this paper we discuss about the design and development of an “Autonomous Amphibious Unmanned Aerial Vehicle (AAUAV)” that can fly autonomously to the polluted water areas where human accessibility is formidable to test the water quality. The AAUAV system is an integrated multi-copter with tilt rotor capability to facilitate easy landing, navigation and maneuver on water. A 3D CAD model has been designed and analyzed. A specific propulsion system has been devised and lab tested. A proof of concept model has been made and tested in the field with its instruments to ascertain its technical/ operational feasibility. This system can also be tailored to collect and store the water samples from the polluted sites for further comprehensive research at the laboratory. AAUAV system is the novel solution to the polluted environment through a complete integrated system. This will be an effective alternative for the conventional water sampling techniques.

Parvez Alam, M., Manoharan, Dinesh

Aircraft Weight and Center of Mass Estimation System

2016-01-202509/20/2016

Aircraft weight and center of mass are two critical design and operational parameters that have to be within a design envelope to ensure a safe and efficient operation of aircraft. Previous efforts to accurately determine aircraft weight and center of mass before takeoff using landing gear shock strut pressures have failed due to the distortion of measured pressures by shock strut seal friction. Currently, aircraft loading process is controlled with loading sheets and passenger/cargo weight estimation as there are no online measurement systems that can accurately and efficiently estimate aircraft weight and determine the center of mass location before takeoff. However, errors in loading sheets, shifting cargo and errors in weight estimation could lead to incorrect loading of aircraft and, consequently, increase the risk of accidents, particularly in cargo flights. In this paper, an online weight measurement system that can determine an aircraft weight and its center of mass before

Fazeli, Amir, Cepic, Adnan, Reber, Susanne

Technology of Cut-Glue Approximation Method for Modeling Strongly Nonlinear Multivariable Objects. Theoretical Bases and Prospects of Practical Application

2016-01-203509/20/2016

The main difficulties of the mathematical models vehicles creation are defined by strongly nonlinearity of dependences which connect various variables their states and conditions of the movement environment. Most it belongs to aircrafts as aerodynamic interactions are characterized by essential nonlinearity up to discontinuity of variables and their derivatives. Creation process of these models is complicated by high-dimensionality, characteristic for the mechanical movement laws. Experimental creation of the mathematical models (MM) of such dependences is carried out by various mathematical methods of approximation of data. Universal remedies of the solution of the formulated task don't exist. Each of it possesses both benefits, and considerable shortcomings. In this regard the possibilities of a method creation of high-precision analytical approximations of the strongly nonlinear dependences using the analytical functions have been investigated. The Cut-Glue approximation (CGA

Neydorf, Rudolf, Neydorf, Anna

Achieving a Realistic Model of Flight Dynamics and Aeroelasticity of Flexible Aircraft

TBMG-2494307/01/2016

Researchers at NASA’s Armstrong Flight Research Center have developed a method that allows for the translation of frequency-domain aerodynamics from commercial code (e.g., ZAERO™ or NASTRAN®) to a time-domain formulation that can be easily understood by flight control engineers, and eliminates the complications inherent in previous methods. These previous methods were designed for structural control (independent of flight dynamics) and are therefore formulated in the inertial (stationary) modal reference frame, which cannot accurately capture phugoid mode dynamics without significant complexity. Thus, a non-inertial reference frame was required to correctly model flight dynamics — a goal previously achieved by applying a transformation to the final statespace model. However, the transformation method created numerical errors, leading to problems in model simulation, reduction of the order-for-control development, and decreased accuracy.

Improved Ground Collision Avoidance System for General Aviation Aircraft and UAVs

TBMG-2364601/01/2016

Controlled flight into terrain (CFIT) causes almost 100 deaths each year in the United States. Although warning systems have virtually eliminated CFIT for large commercial air carriers, the problem still remains for general aviation aircraft and unmanned aerial vehicles (UAVs). Existing systems are forced to rely on digital maps with low resolution/fidelity. They also require expensive equipment, limit the maneuvers to avoid collision, and frequently issue false alarms, causing pilots to ignore the safety system.

Graphical Input-Output Visualization Tool for DAVE-ML Models

TBMG-2368401/01/2016

Adopters of the AIAA/ANSI Standard S119, “Flight Dynamics Model Exchange Standard,” are required to deal with models encoded using DAVE-ML, an XML grammar. While examining the model via a text editor, the ability to visualize nonlinear mappings between input and output signals is not easy. This innovation provides a simple, easy-to-use, standalone Java application that provides the capability to examine the response of the model to combinations of input values. The models are encoded in XML, which is text-based.

Satellite Situation Update

TBMG-23228

11/01/2015

Satellite Situation Update (SSUP) software shows the current locations of a selected set of orbiting spacecraft, along with each satellite’s ground track and/or orbit shape. SSUP is intended as a real-time display, showing multiple spacecraft, that is suitable for a large wall monitor meant to be in public spaces for the appreciation of a wider audience. Satellite positions are constantly updated to stay current, based on either publicly available information (e.g. Celestrak) or other sources [by arrangement with Flight Dynamics Facility (FDF)]. The user chooses the spacecraft to be monitored, as well as other configuration parameters. SSUP is intended for education and outreach purposes; it is a way for an organization to, for example, take pride in the spacecraft they had a role in building or operating. SSUP also is an attractive way to stimulate interest in Earth-Sun-Moon relationships and basic orbital geometries.

Autonomous Micro Aerial Vehicle Flight Using Optical Flow and Inertial Cues

TBMG-2322911/01/2015

Micro aerial vehicles (MAVs) are agile and have unstable flight dynamics. They require a failsafe method to be navigated through areas even without GPS coverage. The approach of this work is to use only the feature matches between two consecutive images, i.e. optical flow (OF) and inertial cues. The vehicle’s pose and additional intrinsic as well as extrinsic states are estimated continuously to navigate and control the MAV through the area. Optical flow cues and inertial measurement readings are fused in an EKF (extended Kalman filter) framework to estimate a metric 3D body velocity, terrain plane-parameters, terrain plane relative 3D attitude including heading, and metric distance between the camera on the MAV and this plane. The estimates of the EKF provide the vehicle controller with accurate information about the vehicle and the environment in order to navigate the micro-helicopter autonomously through large areas. The system is fully self-contained and all computation is done

Design, Manufacturing and Testing of a Long Endurance UAV - Effect of Control Simulations

2015-36-036409/22/2015

A long endurance high efficiency Unmanned Aerial Vehicle (UAV) is being developed by a group of researchers and students in the Mechanical Engineering Technology program at Algonquin College, Ottawa, ON, Canada. The design is based on a tailless, staggered tandem wing configuration, with a carbon fiber frame and electric propulsion. The developed aircraft has a maximum weight of 12.5 kg, well within the 25 kg limit outlined by Transport Canada for permission-free operation. The UAV was designed to fly missions exceeding 24 hours, performing surveillance and oil pipeline monitoring and inspection, either autonomously or under radio control from a ground station, with medium to high payload capacity. This paper describes the process of designing, manufacturing and testing the developed configuration. The operational requirements are delineated as conceptualized by the development team. A description of the prototype development, including aerodynamics, structural and stability

Spuldaro, Everton, Donoghue, Justin, Hough, Jacob, Rocha, Bruno

Bivariate “Cut-Glue” Approximation of Strongly Nonlinear Mathematical Models Based on Experimental Data

2015-01-239409/15/2015

Researchers meet the difficulties of experimental and computer modeling of a statics and dynamics of aircrafts connected with their essential nonlinearity. This is due to the fact that the aerodynamic effects of the interaction complex aircraft designs or their models with air environment generate abrupt changes of the character of the some dependencies. Aerodynamic coefficients in the model of interaction can be obtained only or by full-scale tests or by computer simulations. Therefore, the construction of mathematical models of the objects is associated with the mathematical processing of the points of the experimental data. In this case, the experimentally obtained dependence is usually essentially nonlinear up to piecewise, or even discontinuous nature. Approximation of such dependencies, even with the use of spline functions, is very difficult and is associated with large errors. The solution to this problem was proposed by the author and was reported to the ASME Congress in

Neydorf, Rudolf

Technology Innovations in World War I Airplane Design

2015-01-258109/15/2015

World War 1 began with the airplane as a frail, unarmed means of observing enemy troop movements and ended with the airplane as a powerful, much more evolved weapon of war. There were specialized roles for fighter, bomber and ground attack aircraft as well as newly developed aerial strategies and tactics for operational effectiveness. Many aircraft design technologies greatly matured during the war. Four will be the subject of this paper: Drag reduction, aircraft handling qualities, stability and control, airfoil design technology, and structures design technology. Propulsion and armament also matured greatly but are not discussed in the paper. The discussion of drag reduction will illustrate the innovations of the British on external wire bracing drag, the French on cowl design and the Germans on cantilevered wings and induced drag. Control surfaces and handling will show the invention of balanced controls, and the use of the equations of motion to design specific handling properties

Eberhardt, Scott

NDI-Based Controller for Acheon-Based Thrust Vectoring of Aircraft

2015-01-246809/15/2015

Nonlinear Dynamic Inversion (NDI) has been previously reported for application to unmanned aircraft systems, due to the inherent attributes of allowing global co-ordinates to be used directly as control inputs. Here, the paper describes a model implementation of an ACHEON propulsion/thrust vectoring system that can be applied to a range of aircraft, with specific emphasis to thrust vectoring of a UAV. Results from the studies show the overall performance is shown to provide improved stability and dynamic characteristics when augmented with additional classical (PI based) control schemes.

Margetts, Rebecca, Bingham, Chris, Smith, Tim

Development of a High-Fidelity Simulation Model for a Research Environment

2015-01-256909/15/2015

During aircraft development, mathematical models are elaborated from our knowledge of fundamental physical laws. Those models are used to gain knowledge in order to make the best decisions at all development stages. Depending on the application, different models can be used to describe, in one way or another, the aircraft behavior. The goal of this paper is to develop a high-fidelity aircraft simulation model that is exceptionally capable, flexible and responsive to the needs of the researchers. The proposed model includes nonlinear aerodynamic coefficients, a generic engine model and a complete autopilot with auto-landing. The simulation model has been designed to help researchers develop and validate new algorithms for trajectory optimization, control design, stability analysis and parameter estimation. To make it easy to use, the simulation model also includes algorithms for stability and control analysis. Methodologies based on Nelder-Mead's optimization algorithm with a friendly

Ghazi, Georges, Botez, Ruxandra

Validation and Update of Aerodynamic Database at Extreme Flight Regimes

2015-01-256709/15/2015

Aerodynamic database update from the flight tests using system identification techniques is a crucial tool for the development of control laws and high fidelity simulators. For the certification of aircraft under test, aero-database needs to be validated from flight tests throughout the flight envelope and also to certain levels beyond the envelope boundaries. Validation of aero-database close to envelope boundaries entails additional complexities which necessitates careful handling of flight data identification and update process. This paper discusses the approach adopted for aero-database update and flight clearance, followed by a discussion on the issues relevant in the extreme flight test regimes, such as, flow angle accuracy at higher angles-of-attack, center-of-gravity variation with fuel pitch angle for high-g maneuvering conditions and inaccuracies in Mach number at transonic speeds. Results from flight data identification of a high performance aircraft with relaxed static

Kaliyari, Dushyant, Nusrath TK, Khadeeja, Singh, Jatinder

Investigation of GNSS Integrity Augmentation Synergies with Unmanned Aircraft Sense-and-Avoid Systems

2015-01-245609/15/2015

Global Navigation Satellite Systems (GNSS) can support the development of low-cost and high performance navigation and guidance architectures for Unmanned Aircraft Systems (UAS) and, in conjunction with suitable data link technologies, the provision of Automated Dependent Surveillance (ADS) functionalities for cooperative Sense-and-Avoid (SAA). In non-cooperative SAA, the adoption of GNSS can also provide the key positioning and, in some cases, attitude data (using multiple antennas) required for automated collision avoidance. A key limitation of GNSS for both cooperative (ADS) and non-cooperative applications is represented by the achievable levels of integrity. Therefore, an Avionics Based Integrity Augmentation (ABIA) solution is proposed to support the development of an Integrity-Augmented SAA (IAS) architecture suitable for both cooperative and non-cooperative scenarios. The performances of this IAS architecture were investigated in representative simulation case studies by

Sabatini, Roberto, Moore, Terry, Hill, Chris, Ramasamy, Subramanian

Development of Variable Camber Continuous Trailing Edge Flap for Performance Adaptive Aeroelastic Wing

2015-01-256509/15/2015

This paper summarizes the recent development of an adaptive aeroelastic wing shaping control technology called variable camber continuous trailing edge flap (VCCTEF). As wing flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. The initial VCCTEF concept was developed in 2010 by NASA under a NASA Innovation Fund study entitled “Elastically Shaped Future Air Vehicle Concept,” which showed that highly flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and bending deflection in order to optimize the spanwise lift distribution for drag reduction. A collaboration between NASA and Boeing Research & Technology was subsequently funded by NASA from 2012 to 2014 to further develop the VCCTEF concept. This

Nguyen, Nhan, Lebofsky, Sonia, Ting, Eric, Kaul, Upender, Chaparro, Daniel, Urnes, James

Spy Blimps Revisited: A Performance Comparison between Two Competing Approaches

2015-01-257909/15/2015

While operational airships globally number in the low dozens, interest in buoyant or semi-buoyant platforms continues to arouse imaginations of commercial and military planners and developers alike. The airship-as-advertisement business model is the only model that has proven sustainable on any scale since the crash of the initially successful LZ-128 Hindenburg effectively ended regular passenger and cargo transport by airship, and the 1962 termination of the US Naval airship program terminated regular large-scale surveillance from airships. Efforts in the US and Japan during the 2000's to have a self-sustaining sight-seeing business model using the modern semi-rigid Zeppelin NT both failed. In theory, the buoyant nature of airships provides compelling endurance and cost-per-ton-mile capability which fills a niche arguably not currently occupied by other modes of transportation. The potential endurance capability motivated the US Military to fund two nearly-simultaneous airship

Buerge, Brandon Todd

Automated ATM System Enabling 4DT-Based Operations

2015-01-253909/15/2015

As part of the current initiatives aimed at enhancing safety, efficiency and environmental sustainability of aviation, a significant improvement in the efficiency of aircraft operations is currently pursued. Innovative Communication, Navigation, Surveillance and Air Traffic Management (CNS/ATM) technologies and operational concepts are being developed to achieve the ambitious goals for efficiency and environmental sustainability set by national and international aviation organizations. These technological and operational innovations will be ultimately enabled by the introduction of novel CNS/ATM and Avionics (CNS+A) systems, featuring higher levels of automation. A core feature of such systems consists in the real-time multi-objective optimization of flight trajectories, incorporating all the operational, economic and environmental aspects of the aircraft mission. This article describes the conceptual design of an innovative ground-based Air Traffic Management (ATM) system featuring

Gardi, Alessandro, Sabatini, Roberto, Ramasamy, Subramanian, Marino, Matthew, Kistan, Trevor

Simulation-Driven Methodology for the Requirements Verification and Safety Assessment of Innovative Flight Control Systems

2015-01-247809/15/2015

The paradigm shift to focus on an enhancement of existing aircraft systems raises the question which of the many possible incremental improvements results in an advantageous solution still considering all existing requirements. Hence, new methodologies for aircraft system design are a prerequisite to cope with such huge and complex design spaces. In the case of flight control system optimization, major design variables are the control surface configuration and actuation as well as their functional allocation. Possible architecture topologies have to be verified inter alia with respect to system safety requirements. In this context, flight dynamic characteristics and handling qualities of the fully operational as well as of several degraded system states of each topology have to be evaluated and checked against common specifications. A model-based verification of the requirements is favorable, resulting in a rapid reduction of the design space. Safety objectives for valid configurations

Kreitz, Tobias, Bornholdt, Riko, Krings, Matthias, Henning, Karsten, Thielecke, Frank

FMS and AFCS Interface for 4D Trajectory Operations

2015-01-245809/15/2015

The future revolution of the air traffic system imposes the development of a new class of Flight Management Systems (FMS), capable of providing the aircraft with real-time reference flight parameters, necessary to fly the aircraft through a predefined sequence of waypoints, while minimizing fuel consumption, noise and pollution emissions. The main goal is to guarantee safety operations while reducing the aircraft environmental impact, according to the main international research programs. This policy is expected to affect also the Unmanned Aerial Systems (UASs), as soon as they will be allowed to fly beyond the restricted portions of the aerospace where they are currently confined. In the future, in fact, UASs are expected to fly within the whole civilian airspace, under the same requirements deriving from the adoption of the Performance Based Navigation (PBN). For UASs, the most attractive strategy to reach this goal consists in adopting the mature technology developed for the civil

Sirigu, Giuseppe, Battipede, Manuela, Gili, Piero, Cassaro, Mario

Comparative Usage of Two Similar Airframes

2015-01-900609/01/2015

In-service data from two Bombardier business jets, a Global 5000 and a Global Express XRS, have been compared. Flight data has been analyzed from both airframes with comparable number of ground-air-ground cycles. Individual flight phase have been examined and compared between the two airframes. Primary emphasis has been placed on airframe usage. The influence of primary mission on ground-air-ground cycles has been highlighted in the form of ground and flight loads, as well as dynamics of the flights. It is demonstrated that safe-life maintenance approach may have to be adjusted to account for the airframe usage.

Kliment, Linda, Rokhsaz, Kamran

Ad Hoc Adaptive Pitch Axis Pilot Model

TBMG-2178704/01/2015

Flight research has shown that adaptive flight control systems can be susceptible to adverse pilot-controller interactions, including pilot-in-the-loop oscillations (PIO). Conventional PIO analysis is performed using a static pilot model and a linear, time-invariant model of the aircraft and its control system. For aircraft with time-varying dynamics such as damage or failure, pilot technique may change rapidly to maintain control. An adaptive pilot model can be used to evaluate potential interactions between the pilot and an adaptive flight controller.

Researchers Develop Multiphysics Model for Electro-Thermal Analysis of UAV

TBMG-21186

12/01/2014

Vives College University and Kulab (KU Leuven University campus Ostend) in Belgium are undertaking an aeronautical research program for the development of a new UAV aimed at performing scientific missions along the Belgian coastline above the North Sea. The main performance requirement of the UAV, dubbed Litus, is to be electrically powered with a range of 160 km and a payload up to 5 kg.