Accurate delivery of cargo from air to ground is currently performed using autonomously guided pa... more Accurate delivery of cargo from air to ground is currently performed using autonomously guided parafoil systems. These parafoils offer limited maneuverability and accuracy, and are often relatively complex systems with significant deployment uncertainty. The author has proposed, designed, and developed a novel precision airdrop system in the form of a samara. Consisting of a single wing, payload, and control system, the guided samara is mechanically simple, and when correctly configured, is globally stable during deployment and steady descent. The proposed control mechanisms grant the vehicle omni-directional glide slope control during autorotating descent. This is the first documented effort to develop an actively controlled vehicle of this form factor. The research presented in this thesis includes the conceptual design of the vehicle and several
L'invention concerne un avion comprenant une soufflante canalisee et un moteur pour entrainer... more L'invention concerne un avion comprenant une soufflante canalisee et un moteur pour entrainer cette soufflante canalisee. Cet avion comprend une pluralite d'ailettes montees mobiles sur l'avion a une extremite d'echappement sensiblement rectangulaire de l'avion. Chaque ailette est sensiblement rectangulaire ou carree. La pluralite d'ailettes est configuree pour modifier une zone de sortie de l'extremite d'echappement. L'avion comprend un circuit de detection pour detecter un regime du moteur ou pour produire un signal de regime. Cet avion comprend un circuit de commande relie au circuit de detection et a la pluralite d'ailettes. Le circuit de commande est concu pour actionner la pluralite d'ailettes pour modifier la zone de sortie de l'extremite d'echappement, de sorte a faire varier la charge de pression sur la soufflante canalisee, pour commander le regime du moteur, en reaction au signal de regime.
This chapter contains sections titled: D.1 Geometry and Problem Formulation, D.2 First-Order Solu... more This chapter contains sections titled: D.1 Geometry and Problem Formulation, D.2 First-Order Solution, D.3 First-Order Force and Moment Calculation, D.4 Second-Order Solution
This paper presents a description of the physical principles of aerodynamic power savings from bo... more This paper presents a description of the physical principles of aerodynamic power savings from boundary layer ingestion propulsion and a quantitative evaluation of the boundary layer ingestion bene...
This paper presents experimental measurements of propulsive power reduction due to boundary layer... more This paper presents experimental measurements of propulsive power reduction due to boundary layer ingestion, for an electric ducted fan propulsor behind a NACA 0040 body of revolution at a Reynolds number of approximately 240,000. The propulsive power is defined as the electrical power required by the propulsor to obtain a zero net streamwise force on the body/propulsor combination, mimicking the cruise condition for an aircraft. The benefits of the boundary layer ingestion are quantified as a power saving coefficient, or ratio relative to the no-ingestion case where the propulsor is isolated from the wake. The measurements show a maximum power savings when the propulsor is closest to the body centered on the body axis, with savings of 26% for an untripped flow case and 29% for a tripped flow case. A second iteration of experiments were performed, showing a maximum power savings of 25% for a tripped flow case. Propulsor locations farther downstream and further off-axis show progressively smaller power saving benefits. An uncertainty analysis is performed to verify the measurements to within 99% confidence. Wake profiles were also measured to confirm that the wake was fully ingested for on-axis propulsor locations.
We present a novel closed-circuit ultra-compact wind tunnel with an 8:1 contraction ratio and hig... more We present a novel closed-circuit ultra-compact wind tunnel with an 8:1 contraction ratio and high flow quality. Its overall footprint area is less than half that of a conventional tunnel with the same test section size and same contraction ratio, enabling significantly smaller material and construction costs. The tunnel’s key features which enable the small footprint include a two-dimensional main diffuser, a minimum-length contraction, and expanding turning vanes with a 1.167:1 ratio in corner two and an aggressive 1.875:1 ratio in corner four. Separation in the latter is prevented using a screen and honeycomb integrated into each vane passage—the first time this has been used in a wind tunnel. The tunnel exhibits excellent flow quality with less than $$\pm 1$$ ± 1 % mean flow variation in the test section core and a freestream turbulence level of 0.03% at 12 m/s over a 4 Hz–20kHz bandwidth. Graphical abstract
This article presents first-of-a-kind measurements, and complementary computations, of the flow t... more This article presents first-of-a-kind measurements, and complementary computations, of the flow through the propulsion system of a boundary layer ingesting, twin-engine advanced civil transport aircraft configuration. The experiments were carried out in the NASA Langley 14- by 22-foot Subsonic Tunnel, using a 1:11 scale model of the D8 “double-bubble” aircraft with electric ducted fans providing propulsive power. Overall force and moment measurements and flow field surveys at the inlet and nozzle exit planes were obtained. The computations were carried out with the NASA OVERFLOW code. The measurements and computations were conducted for a range of aircraft angles of attack and propulsor powers representing operating points during the aircraft mission. Velocity and pressure distributions at the propulsor inlet and exit, and integral inlet distortion metrics, are presented to quantify the flow nonuniformity due to boundary layer ingestion. The distorted inflow exhibits qualitative and...
This book is intended to serve a diverse audience of students, scientists and engineers who are i... more This book is intended to serve a diverse audience of students, scientists and engineers who are interested in understanding and utilizing the concepts of flight dynamics. The following notes provide to the reader the basic principles based on a classical analytical approach. The concepts of controllability and maneuverability are detailed starting from the definition of stability and control of the equilibrium states. Equations for the estimation of hinge moments and stick force in steady and maneuvering flight are provided. The equations of motion are then extended to unsteady flight and a detailed analytical model is derived for dynamic stability analysis, including an interpretation of stability and control derivatives. Modal response of the vehicle in the longitudinal and lateral-directional plane is also reconstructed. The problems inherent to the evaluation of the flying qualities of a fixed-wing aircraft and the elements of parameter identification are also introduced. Finally, open and closed loop response to controls is discussed both in time and frequency domain
XFOIL-An analysis and design system for low Reynolds number airfoils. ... panel method with a Kar... more XFOIL-An analysis and design system for low Reynolds number airfoils. ... panel method with a Karman-Tsien compressibility correction is developed for direct and mixed-inverse modes. ... are treated, with an e exp 9-type amplification formulation determining the transition point. ...
Accurate delivery of cargo from air to ground is currently performed using autonomously guided pa... more Accurate delivery of cargo from air to ground is currently performed using autonomously guided parafoil systems. These parafoils offer limited maneuverability and accuracy, and are often relatively complex systems with significant deployment uncertainty. The author has proposed, designed, and developed a novel precision airdrop system in the form of a samara. Consisting of a single wing, payload, and control system, the guided samara is mechanically simple, and when correctly configured, is globally stable during deployment and steady descent. The proposed control mechanisms grant the vehicle omni-directional glide slope control during autorotating descent. This is the first documented effort to develop an actively controlled vehicle of this form factor. The research presented in this thesis includes the conceptual design of the vehicle and several
L'invention concerne un avion comprenant une soufflante canalisee et un moteur pour entrainer... more L'invention concerne un avion comprenant une soufflante canalisee et un moteur pour entrainer cette soufflante canalisee. Cet avion comprend une pluralite d'ailettes montees mobiles sur l'avion a une extremite d'echappement sensiblement rectangulaire de l'avion. Chaque ailette est sensiblement rectangulaire ou carree. La pluralite d'ailettes est configuree pour modifier une zone de sortie de l'extremite d'echappement. L'avion comprend un circuit de detection pour detecter un regime du moteur ou pour produire un signal de regime. Cet avion comprend un circuit de commande relie au circuit de detection et a la pluralite d'ailettes. Le circuit de commande est concu pour actionner la pluralite d'ailettes pour modifier la zone de sortie de l'extremite d'echappement, de sorte a faire varier la charge de pression sur la soufflante canalisee, pour commander le regime du moteur, en reaction au signal de regime.
This chapter contains sections titled: D.1 Geometry and Problem Formulation, D.2 First-Order Solu... more This chapter contains sections titled: D.1 Geometry and Problem Formulation, D.2 First-Order Solution, D.3 First-Order Force and Moment Calculation, D.4 Second-Order Solution
This paper presents a description of the physical principles of aerodynamic power savings from bo... more This paper presents a description of the physical principles of aerodynamic power savings from boundary layer ingestion propulsion and a quantitative evaluation of the boundary layer ingestion bene...
This paper presents experimental measurements of propulsive power reduction due to boundary layer... more This paper presents experimental measurements of propulsive power reduction due to boundary layer ingestion, for an electric ducted fan propulsor behind a NACA 0040 body of revolution at a Reynolds number of approximately 240,000. The propulsive power is defined as the electrical power required by the propulsor to obtain a zero net streamwise force on the body/propulsor combination, mimicking the cruise condition for an aircraft. The benefits of the boundary layer ingestion are quantified as a power saving coefficient, or ratio relative to the no-ingestion case where the propulsor is isolated from the wake. The measurements show a maximum power savings when the propulsor is closest to the body centered on the body axis, with savings of 26% for an untripped flow case and 29% for a tripped flow case. A second iteration of experiments were performed, showing a maximum power savings of 25% for a tripped flow case. Propulsor locations farther downstream and further off-axis show progressively smaller power saving benefits. An uncertainty analysis is performed to verify the measurements to within 99% confidence. Wake profiles were also measured to confirm that the wake was fully ingested for on-axis propulsor locations.
We present a novel closed-circuit ultra-compact wind tunnel with an 8:1 contraction ratio and hig... more We present a novel closed-circuit ultra-compact wind tunnel with an 8:1 contraction ratio and high flow quality. Its overall footprint area is less than half that of a conventional tunnel with the same test section size and same contraction ratio, enabling significantly smaller material and construction costs. The tunnel’s key features which enable the small footprint include a two-dimensional main diffuser, a minimum-length contraction, and expanding turning vanes with a 1.167:1 ratio in corner two and an aggressive 1.875:1 ratio in corner four. Separation in the latter is prevented using a screen and honeycomb integrated into each vane passage—the first time this has been used in a wind tunnel. The tunnel exhibits excellent flow quality with less than $$\pm 1$$ ± 1 % mean flow variation in the test section core and a freestream turbulence level of 0.03% at 12 m/s over a 4 Hz–20kHz bandwidth. Graphical abstract
This article presents first-of-a-kind measurements, and complementary computations, of the flow t... more This article presents first-of-a-kind measurements, and complementary computations, of the flow through the propulsion system of a boundary layer ingesting, twin-engine advanced civil transport aircraft configuration. The experiments were carried out in the NASA Langley 14- by 22-foot Subsonic Tunnel, using a 1:11 scale model of the D8 “double-bubble” aircraft with electric ducted fans providing propulsive power. Overall force and moment measurements and flow field surveys at the inlet and nozzle exit planes were obtained. The computations were carried out with the NASA OVERFLOW code. The measurements and computations were conducted for a range of aircraft angles of attack and propulsor powers representing operating points during the aircraft mission. Velocity and pressure distributions at the propulsor inlet and exit, and integral inlet distortion metrics, are presented to quantify the flow nonuniformity due to boundary layer ingestion. The distorted inflow exhibits qualitative and...
This book is intended to serve a diverse audience of students, scientists and engineers who are i... more This book is intended to serve a diverse audience of students, scientists and engineers who are interested in understanding and utilizing the concepts of flight dynamics. The following notes provide to the reader the basic principles based on a classical analytical approach. The concepts of controllability and maneuverability are detailed starting from the definition of stability and control of the equilibrium states. Equations for the estimation of hinge moments and stick force in steady and maneuvering flight are provided. The equations of motion are then extended to unsteady flight and a detailed analytical model is derived for dynamic stability analysis, including an interpretation of stability and control derivatives. Modal response of the vehicle in the longitudinal and lateral-directional plane is also reconstructed. The problems inherent to the evaluation of the flying qualities of a fixed-wing aircraft and the elements of parameter identification are also introduced. Finally, open and closed loop response to controls is discussed both in time and frequency domain
XFOIL-An analysis and design system for low Reynolds number airfoils. ... panel method with a Kar... more XFOIL-An analysis and design system for low Reynolds number airfoils. ... panel method with a Karman-Tsien compressibility correction is developed for direct and mixed-inverse modes. ... are treated, with an e exp 9-type amplification formulation determining the transition point. ...
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