A computer graphics simulation of an aircraft Head-Up Display was designed using an RDS-3000 Ikonas Graphics Processor and a PDP-11/34 host computer system. The software control and display modules were accomplished using Ikonas microcode and Digital Equipment Corporation Fortran IV-PLUS. The Head-Up Display system consists of the basic flight data, which includes aerodynamic flight information, Roll/Pitch Ladder, and the Velocity Vector or Flight Path Marker. The system was designed for flexibility in modifications and evaluation of various weapons delivery systems. These will be adapted to specific needs by research scientists and engineers at the Visual Technology Research Simulator in Orlando, Florida.

The problem of aircraft control allocation is that of finding a combination of control positions that cause the resulting aircraft moments to most closely satisfy a given desired moment vector. The problem is easily solved for the case of an aircraft having three control surfaces, each of which primarily imparts moments in each of the three aircraft axes. In this simple case, the solution to the control allocation problem is uniquely determined. However, many current and future aircraft designs employ a larger set of control effectors, resulting in a control redundancy in the sense that more than one combination of control positions can produce the same desired moment. When taking into account both the position and rate constraints of the control effectors, the problem is significantly more complex. Constrained moment-rate control allocation guarantees a control solution that can achieve every possible moment that is physically realizable by the aircraft. Addressed here is the real-time performance of moment-rate constrained control allocation as tested on a desktop simulation. Issues that were deemed interesting or potentially problematic in earlier batch simulation, such as control chattering due to restoring and apparent control wind-up, are investigated and an evaluation is made of the overall feasibility of these algorithms. The purpose of the research is to confirm that the results obtained from batch simulation testing are also valid using maneuvers representative of real-time flight and representative simulation frame sizes, and to uncover potential problems not observed in batch simulation. NOTE: An updated copy of this ETD was added on 05/29/2013. / Master of Science

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper discusses the methodology, requirements, tests, and implementation plan for the live demonstration of the Enhanced Flight Termination System (EFTS) using a missile program at two locations in Florida: Eglin Air Force Base (AFB) and Tyndall AFB. The demonstration included the integration of EFTS Flight Termination Receivers (FTRs) onto the missile and the integration of EFTS-program-developed transmitter assets with the mission control system at Eglin and Tyndall AFBs. The initial test stages included ground testing and captive-carry flights, followed by a launch in which EFTS was designated as the primary flight termination system for the launch.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / As the size of missiles and UAVs shrink, so does the volume available for the Flight Termination System (FTS). Small, light weight FTS systems open up applications not possible with the larger and heavier conventional FTS systems. This paper presents a novel approach for the design, implementation and test of a subminiature Flight Terminate System Receiver for use in the Subminiature Flight Safety System (SFSS). This receiver implements the new digital-based Enhanced Flight Termination System (EFTS) protocol, while maintaining a volume of less than 1 cubic inch with power consumption of less than 2 watts. Combining all of the necessary functionality into a small package while meeting the rigorous requirements of the Range Commanders Council (RCC) specifications (EMI, vibration and shock) presented significant challenges. The Subminiature Enhanced Flight Termination Receiver used in the SFSS has been named the "SEFTR".

During the period 1980 to 2008 there were 359 fatal accidents involving UK registered light aeroplanes of which 36% occurred in visual meteorological conditions. In all, 216 lives were lost with accidents being attributed to the pilot 'failing to maintain proper control resulting in a stall or spin'. Dissimilar fatal stallrelated accident rates are evident for aeroplane makes & models of similar design. During the course of this programme of research, flight testing of two similar aeroplane models using a case study method showed marked differences in the variation of stick force with airspeed or stick force gradient in all flight conditions. This suggested that 'control feel' was a contributory factor towards the pilot’s failure to maintain proper control. Current certification standards for light aeroplanes rely upon the subjective assessment of stick force gradients by test pilots, requiring that substantial changes in airspeed are accompanied by clearly perceptible changes in stick force with no specified minimum gradient. This programme of research has been carried out to determine acceptable criteria for stick force gradients of a light aeroplane in all flight conditions. Criteria has been determined from flight tests of aeroplanes with different in-service safety records and subjective pilot workload assessment using simulated flying tasks with different stick force gradients performed by twenty GA pilots. Simulation tests indicated that pilot mental demand increased significantly (p > 0.05) when stick force gradient was reduced to ‘zero’, representing an aeroplane with neutral longitudinal static stability. A predictive model has been developed to estimate stick force gradients for a light aeroplane in any flight condition under quasi-static, longitudinal, non-manoeuvring flight and 1-g loading conditions. The model builds upon previous published work limited to cruising flight, and enables the estimation of stick forces and gradients due to high lift devices in the climb and landing condition by consideration of the combined effects of wing loading, CG, elevator gearing, flaps and elevator trim setting. Implemented using MATLAB, the model has been validated by comparing with flight test results for the case study aeroplanes and showed mean differences of ±0.025 daN/kt. The predictive model should be used in preliminary aeroplane design to assess tendencies towards neutral stability in high workload, safety critical flight conditions such as the take-off and landing. In addition, the model should be used to analyse existing aeroplanes with comparatively low or neutral stick force gradients in safety critical flight phases and to predict the effects of changing CG and/or flap limits to increase stick force gradient and improve control feel. The combined results of these studies suggest that a minimum acceptable stick force gradient for a non-aerobatic light aeroplane in all flight conditions should be nonzero and between 0.10~0.13 daN/kt. A stable and predictable stick force variation with airspeed will ensure that any substantial deviation from trimmed airspeed is accompanied by a stick force change clearly perceptible to the pilot and also provide additional warning of the proximity to the stall. The use of specific criteria to complement qualitative test pilot opinion, will assist in confirming compliance and provide consistency with current standards for sailplanes/powered sailplanes and large commercial aeroplanes, both of which already have defined minimum acceptable gradients.

Este trabalho apresenta os principais conceitos de um modelo de referência, chamado de Consciência Situacional em Voo (In-Flight Awareness, IFA), e sua implementação embarcada IFA2S (In-Flight Awareness Augmentation System). IFA é um conceito novo e realista e voltado à melhoria da segurança de voo de VANTs. IFA2S tem o potencial de alavancar confiabilidade dos VANTs aos níveis encontrados na aviação geral. Ele aumenta a consciência aeronave tanto em relação a si mesma e seu ambiente circundante e, ao mesmo tempo reconhece restrições da plataforma para agir de acordo com algoritmos de decisão pré-definidos. Este trabalho apresenta o IFA como consequência dos requisitos de segurança estabelecidos através da metodologia STPA, faz uma avaliação quantitativa do impacto do IFA2S no risco operacional dos VANTs e apresenta orientações de implementação em hardware. Simulações de validação são realizadas com uso do software Labview e do simulador de voo XPlane. / This work presents the key concepts of IFA, In-Flight Awareness, and its implementation IFA2S (In-Flight Awareness Augmentation System). IFA is a novel and realistic concept intended to enhance flight safety. IFA2S has the potential to leverage UAVs reliability to the levels of general aviation aircraft. It increases aircraft awareness regarding both itself and its environment and, at the same time recognizes platform constraints to act in accordance to predefined decision algorithms. This paper presents the IFA as a consequence of the safety requirements established using STPA methodology, a quantitative assessment of the impact of IFA2S in the operational risk of UAVs as well as suggestions for hardware implementation. Simulations are carried out using Labview software and the flight simulator XPlane.

Demonstration of spanwise-periodic discrete roughness element laminar flow control (DRE LFC) technology at operationally relevant flight regimes requires extremely stable flow conditions in flight. A balance must be struck between the capabilities of the host aircraft and the scientific apparatus. A safe, effective, and efficient flight experiment is described to meet the test objectives, a flight test technique is designed to gather research-quality data, flight characteristics are analyzed for data compatibility, and an experiment is designed for data collection and analysis. The objective is to demonstrate DRE effects in a flight environment relevant to transport-category aircraft: [0.67 – 0.75] Mach number and [17.0M – 27.5M] Reynolds number. Within this envelope, flight conditions are determined which meet evaluation criteria for minimum lift coefficient and crossflow transition location. The angle of attack data band is determined, and the natural laminar flow characteristics are evaluated. Finally, DRE LFC technology is demonstrated in the angle of attack data band at the specified flight conditions. Within the angle of attack data band, a test angle of attack must be maintained with a tolerance of ± 0.1° for 15 seconds. A flight test technique is developed that precisely controls angle of attack. Lateral-directional stability characteristics of the host aircraft are exploited to manipulate the position of flight controls near the wing glove. Directional control inputs are applied in conjunction with lateral control inputs to achieve the desired flow conditions. The data are statistically analyzed in a split-plot factorial that produces a system response model in six variables: angle of attack, Mach number, Reynolds number, DRE height, DRE spacing, and the surface roughness of the leading edge. Predictions on aircraft performance are modeled to enable planning tools for efficient flight research while still producing statistically rigorous flight data. The Gulfstream IIB aircraft is determined to be suitable for a laminar flow control wing glove experiment using a low-bank-angle-turn flight test technique to enable precise, repeatable data collection at stabilized flight conditions. Analytical angle of attack models and an experimental design were generated to ensure efficient and effective flight research.

Este trabalho apresenta os principais conceitos de um modelo de referência, chamado de Consciência Situacional em Voo (In-Flight Awareness, IFA), e sua implementação embarcada IFA2S (In-Flight Awareness Augmentation System). IFA é um conceito novo e realista e voltado à melhoria da segurança de voo de VANTs. IFA2S tem o potencial de alavancar confiabilidade dos VANTs aos níveis encontrados na aviação geral. Ele aumenta a consciência aeronave tanto em relação a si mesma e seu ambiente circundante e, ao mesmo tempo reconhece restrições da plataforma para agir de acordo com algoritmos de decisão pré-definidos. Este trabalho apresenta o IFA como consequência dos requisitos de segurança estabelecidos através da metodologia STPA, faz uma avaliação quantitativa do impacto do IFA2S no risco operacional dos VANTs e apresenta orientações de implementação em hardware. Simulações de validação são realizadas com uso do software Labview e do simulador de voo XPlane. / This work presents the key concepts of IFA, In-Flight Awareness, and its implementation IFA2S (In-Flight Awareness Augmentation System). IFA is a novel and realistic concept intended to enhance flight safety. IFA2S has the potential to leverage UAVs reliability to the levels of general aviation aircraft. It increases aircraft awareness regarding both itself and its environment and, at the same time recognizes platform constraints to act in accordance to predefined decision algorithms. This paper presents the IFA as a consequence of the safety requirements established using STPA methodology, a quantitative assessment of the impact of IFA2S in the operational risk of UAVs as well as suggestions for hardware implementation. Simulations are carried out using Labview software and the flight simulator XPlane.

This thesis presents a comprehensive framework and a study for trajectory optimization based on the patterned formation flying of the aircraft system as well as the maneuvers for deforming the configured and aligned aerial vehicles with safe mode criteria considerations while subjected to typical environmental requirements of aerial-flying zones. The elementary trajectory problem of a simple dynamical point-mass system of the aircraft is mathematically formulated and converted into a simulation version of mathematical programming as finite horizon planning and fixed arrival time planning strategies as an optimization problem. The methodology of the designed framework is mainly concerned with the safer path planning of the aircraft system with testing on all the probable feasibility and safety constraints to incorporate into a mathematical programming design of a collision-free and optimal trajectory characterization. The imperative notion is to create a configurational pattern of the aircraft system based on their creation of wingtip vortices. Flying the aircraft in formation lessen the fuel consumption as well as increase the time efficiency. The aircraft formation is arranged and optimized for safe trajectories during flight operations and for reduction of the carbon footprint of the whole system. Furthermore, deformation maneuvers are incorporated to complete the aircraft planning system by allowing the possibility of safely disassembling the formation for emergency breakout and exit sequences.

Bats have many impressive flight characteristics such as the ability to rapidly change direction, carry substantial loads, and maintain good flight efficiency. For several years, researchers have been working towards an understanding of the specific aerodynamic phenomena which relate the unique wing structure of bats to their flight abilities. Computational fluid dynamics, a powerful tool used extensively across aerospace research, has led to substantial progress in the understanding of insect flight. However, due to technical challenges, numerical simulation has seen limited use in bat flight research. For this research, we develop, validate, and apply computational modeling techniques to three modes of bat flight: straight flight, sweeping turn, and U-turn maneuver. 3D kinematic data collection was achieved using a 28 camera multi-perspective optical motion capture system. The calibration of the cameras was conducted using a multi-camera self-calibration method. Point correspondences between cameras and frames was achieved using a human-supervised software package developed for this project. After the collection of kinematic data, we carried out aerodynamic flow simulations using the incompressible Navier-Stokes solver, GenIDLEST. The immersed boundary method (IBM) was used to impose moving boundary conditions representing the wing kinematics. Validation of the computational model was preformed through a grid independence study as well as careful evaluation of other relevant simulation parameters. Verification of the model was performed by comparing simulated aerodynamic loads to the expected loads based on the observed flight trajectories. Additionally, we established that we had a sufficient resolution of the wing kinematics, by calculating the sensitivity of the simulation results to the number of kinematic markers used during motion capture. For this study, three particular flights are analyzed—a straight and level flight, a sweeping turn, and a sharp 180 degree turn. During straight flight, typical flight velocities observed in the flight tunnel were 2-3 m/s resulting in a Reynolds number of about 12,000. Lift generation occurred almost exclusively during the downstroke, and peaks mid-downstroke. At the beginning of each downstroke, the effective angle of attack of the wings transitions from negative to positive and a leading edge vortex (LEV) quickly forms. LEVs are known to augment lift generation in flapping flight and allow lift to remain high at large angles of attack. During the end of each downstroke, the LEVs break up and lift drops substantially. As the wingbeat cycle transitions from downstroke to upstroke, the wings rotate such that the wing chordline is vertical as the wing moves upward. This wing rotation is critical for mitigating negative lift during the upstroke. Many of the basic flight mechanisms used for straight flight—i.e. LEV formation, wing rotation during upstrokes—were also observed during the sweeping turn. In addition, asymmetries in the wing kinematics and consequently the aerodynamics were observed. Early in the turn, the bank angle was low and elevated levels of thrust were generated by the outer wing during both the upstroke and downstroke causing a yaw moment. As the bat moved towards the middle of the turn, the bank angle increased to 20-25 degrees. Although the bank angle remained nominally constant during the middle and later portion of the turn, there was variation within each wingbeat cycle. Specifically, the bank angle dropped during each upstroke and subsequently was recovered during each downstroke as a consequence of elevated lift on the outer wing. Banking served to redirect the net force vector laterally causing a radial, centripetal force. Considering the mass of the bat, the nominal flight velocity, and the radius of curvature, the magnitude of the radial force fully explained the expected centripetal acceleration during the middle and later portion of the turn. Over the entire turn, yaw was found to be important in initiating the turn while banking was more important during the middle part of the turn. Over the course of 5 wingbeat cycles, the change in bearing angle (direction of flight) was about 45 degrees. Analysis of the U-turn flight showed many of the same characteristics as were observed during the sweeping turn, as well as a few key differences. The bat's ability to rotate its body rapidly appears to be more limited than its ability to change its trajectory. For this reason, the yaw rotation began about one to two cycles before the rapid bearing angle change and was stretched out over several wingbeat cycles. At the apex of the U-turn, the bat combined a high roll angle with a low flight velocity magnitude to very rapidly redirect its bearing direction and negotiate a low radius of curvature flight trajectory. Increases in roll angle occurred almost exclusively during the downstrokes, while both the upstroke and downstroke were active in generating yaw. Elevated thrust on the left outer wing during the end of the upstroke was observed throughout the flight, and elevated drag on the right inside wing did not appear to have an impact on the turn. We hope that this project motivates and facilitates further computational analysis into bat flight aerodynamics. Additionally, the data and findings will be useful for applications such as the design of bioinspired MAVs or flexible membrane energy harvesting technology. / Doctor of Philosophy / Bats have many impressive flight characteristics such as the ability to rapidly change direction, carry substantial loads, and maintain good flight efficiency. A better understanding of the physics of how bats fly can help scientists and engineers build more maneuverable, quieter, and more efficient bioinspired micro air vehicles. This engineering approach leverages the incredible capabilities observed in nature, but requires detailed knowledge of the animal as a prerequisite. Computational fluid dynamics, a powerful tool used extensively across aerospace research, has led to substantial progress in the understanding of animal flight broadly. However, due to technical challenges, numerical simulation has seen limited use in bat flight research. For this research, we develop, validate, and apply computer modeling techniques to the investigation of bat flight aerodynamics. Three particular modes of flight were analyzed—a straight and level flight, a sweeping turn, and a sharp 180 degree turn. During straight flight, typical flight velocities observed in the flight tunnel were 2-3 m/s. Lift generation, the force keeping the bat aloft, occurred almost exclusively during the downstroke, and peaks mid-downstroke. As the wing flap transitions from downstroke to upstroke, the wings rotate such that the wing is vertical as it moves upward. This wing rotation is critical for maximizing lift force during flight. During the sweeping turn, asymmetries in the wing kinematics and consequently the aerodynamics were observed. Early in the turn, the bank angle was low and elevated levels of thrust were generated by the outer wing during both the upstroke and downstroke causing rotation of the bat. As the bat moved towards the middle of the turn, the bank angle increased to 20-25 degrees. Banking served to redirect the net force vector laterally causing a turning force. Over the course of 5 wingbeat cycles, the change in direction of flight was about 45 degrees. Analysis of the U-turn flight showed many of the same characteristics as were observed during the sweeping turn, as well as a few key differences. At the apex of the U-turn, the bat combined a high roll angle with a low flight velocity magnitude to very rapidly redirect its bearing direction and negotiate a low radius of curvature flight trajectory. We hope that this project motivates and facilitates further computer simulations studying bat flight aerodynamics. Additionally, the data and findings will be useful for applications such as the design of bioinspired MAVs or flexible membrane energy harvesting technology.