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Showing 1 to 20 of 30 for “"High Angle of Attack"”.
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Reentry Vehicle Aerodynamics and Control at Very High Angle of Attack
… reentry test vehicle spins during the deployment of the drogue parachute. An experimental aerodynamic study has been conducted at the University of Illinois using a scale model of the X-38 to explore the cause of this problem. A six-component sting balance was used to measure the forces and …
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A comparison of control design options for high angle-of-attack flights
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science.
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High Angle of Attack Forebody Flow Physics and Design Emphasizing Directional Stability
… for understanding the fundamental physics of flowfields over forebody type shapes at low speed, high angle of attack conditions with special emphasis on sideslip has been established. Computational Fluid Dynamics (CFD) has been used to study flowfields over experimentally investigated …
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An Aerodynamic Model for Use in the High Angle of Attack Regime
… reduction methods are developed on the basis of multirate digital signal processing. Since the model is sting mounted, the frequencies associated with sting vibration are included in balance readings thus a linear filter must be used to extract out the aerodynamic responses. To achieve this, a …
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Analysis of the dynamic stability derivatives for high angle of attack aircraft
Modern, high performance aircraft are required to be able to fly and be controlled over a wide variety of flight conditions. In order to predict the aircraft behavior and control requirements over the entire flight regime it is necessary to have a proper aerodynamic model. Flight conditions at high …
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Identification of an Unsteady Aerodynamic Model up to High Angle of Attack Regime
… reduction methods are developed on the basis of multirate digital signal processing techniques. Since the model is sting-mounted to the support system of DyPPiR, the Discrete Fourier Transform (DFT) is first used to identify the frequencies of the elastic modes of sting. Then the sampling rate …
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Direct numerical simulation of an aerofoil at high angle of attack and its control
Detailed analysis of the flow around a NACA0020 aerofoil at moderate low chord Reynolds number (Rec = 2×104) in completely stalled conditions has been carried out by means of Direct Numerical Simulations. The stalled condition is either a steady configuration at a fixed angle of attack (α = 20o) or …
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Analysis of High Angle of Attack Maneuvers to Enhance Understanding of the Aerodynamics of Perching
… aerodynamics, mimicking the flight maneuvers of natural flyers requires a deep understanding of the unsteady flow physics while also demanding the ability to expand the vehicle's flight envelope beyond normal conditions. Experimental and computational investigations are performed to study and …
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Flowfield measurements in the vortex wake of a missile at high angle of attack in turbulence
The flowfield downstream of a vertically-launched surface-to-air missile model at an angle of attack of 50° and a Reynolds number of 1.1 x 10(5) was investigated in a wind tunnel of the Naval Postgraduate School. The goal of this thesis is to experimentally validate the pressure measurement system …
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Measurement of unsteady aerodynamic characteristics of a subscale aerobatic aircraft in high angle-of-attack maneuvers
High angle-of-attack flight testing was performed using the UIUC Subscale Sukhoi, which is a 35% scale, 2.6 m (102 in) wingspan Sukhoi 29S electric model aircraft that was developed at the University of Illinois at Urbana-Champaign. The aircraft was instrumented with a custom sensor data …
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Aerodynamic modeling of a 2-dimensional airfoil with a covert-inspired deployable flap using a discrete vortex method
… by their inability to efficiently perform high-angle-of-attack maneuvers at low Reynolds numbers, while birds seem to perform these maneuvers with little effort. Birds use a passively-deployed feather called the covert feather to correct for flow reversal over their wings during …
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Cascade performance of double circular arc compressor blades at high angles of attack
The design of a cascade wind tunnel for testing of compressor blades at high angle of attack is described. Methods to insure uniform velocity profiles and control of inlet turbulence are discussed. The problem of maintaining two-dimensional flows at high angle of attack was addressed. A tunnel …
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A dynamic model for aircraft poststall departure
An engineering model designed for the analysis of high angle-of-attack flight characteristics is developed and applied to the problem of aircraft poststall departure. The model consists of an aerodynamics package used interactively with a six-degree-of-freedom flight simulator. The aerodynamics are …
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Nonlinear control of an aerobatic RC airplane
An automatic flight controller based on the ideas of backstepping is applied to an aerobatic RC airplane. The controller asymptotically tracks a time-parameterized position reference, and depends on an orientation look-up rule to determine the vehicle orientation from a desired acceleration. A …
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Influence of Wing Planform Shape on the Effectiveness of a Fixed-Slot
<p>This thesis report explores the effect of the Clark-Y wing geometry on lift and drag to use as a reference during aircraft design stage. The different characteristics investigated are fixed slot span, taper ratio, washout, and sweep angle. Plain wings, half slotted wings, and fully slotted wings …
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Analysis of various forced oscillation techniques for obtaining dynamic stability derivatives
… dynamic stability derivatives for aircrafts at high angle of attack are described. From the general equations of motion of an aircraft in space, the perturbation equations of motion are derived for applying to a wind tunnel aircraft model. Data Reduction and test procedures for important dynamic …
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A computational and experimental investigation of the propulsive and lifting characteristics of oscillating airfoils and airfoil combinations in incompressible flow
… an analysis was completed on the effects of a harmonically oscillating airfoil on the pressure gradient of a stationary airfoil. Finally, flow visualization experiments were conducted using a low smoke speed tunnel at the Naval Postgraduate School (NPS). This experiment demonstrated the …
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Modeling and control of an autonomous underwater vehicle with combined foil/thruster actuators
… on this; however, requires an understanding of the vehicles dynamics. In this work, we present the development and analysis of an analytic model of the Sentry AUV. Our goals were to develop a model sufficiently accurate in terms of the mission profile to identify critical vehicle behaviors …
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Adaptive Control of Nonaffine Systems with Applications to Flight Control
… flight control design is based on linearization of the equations of motion around a set of trim points and scheduling gains of linear (optimal) controllers around each of these points to meet performance specifications. For high angle of attack maneuvers and other aggressive flight regimes …
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