scholarly journals Frequency-Domain Bifurcation Analysis of a Nonlinear Flight Dynamics Model

2021 ◽  
Vol 44 (1) ◽  
pp. 138-150
Author(s):  
Duc H. Nguyen ◽  
Mark H. Lowenberg ◽  
Simon A. Neild
Keyword(s):  
Frequency Domain ◽  
Bifurcation Analysis ◽  
Flight Dynamics ◽  
Dynamics Model ◽  
Flight Dynamics Model

scholarly journals Study on longitudinal stability of ducted vertical take-off and landing fixed-wing UAV

2021 ◽  
Vol 39 (4) ◽  
pp. 712-720
Author(s):  
Chunyang Wang ◽  
Zhou Zhou ◽  
Rui Wang ◽  
Kelei Wang
Keyword(s):  
Experimental Data ◽  
Flight Dynamics ◽  
Model Parameters ◽  
Dynamics Model ◽  
Flight Stability ◽  
Aerodynamic Model ◽  
Characteristic Cross Section ◽  
Flight Dynamics Model ◽  
Six Degree Of Freedom ◽  
Blade Element

The longitudinal flight stability of the ducted vertical take-off and landing fixed-wing UAV during the flight state of hovering and transition is studied. Firstly, based on the Blade-Element Momentum Theory (BEMT) and experimental data, a coaxial dual-rotor ducted aerodynamic model and a thrust ducted aerodynamic model based on characteristic cross-section calculations are established. The model parameters are identified according to the experimental data. Secondly, a UAV flight dynamics model with thrust duct deflection is established according to the six-degree-of-freedom equations. Finally, the case UAV was used to solve the longitudinal balance and stability analysis of hovering and transition state with the established model method, and compared with the hovering experimental results. The results show that the UAV flight dynamics model combined with the ducted dynamic model established in the article can accurately describe the longitudinal flight stability characteristics of this type of aircraft.

Pilot Sensitivity to Simulator Flight Dynamics Model Formulation for Stall Training

2019 ◽  
Author(s):  
Kevin Cunningham ◽  
Gautam H. Shah ◽  
Patrick C. Murphy ◽  
Melissa A. Hill ◽  
Brent Pickering
Keyword(s):  
Flight Dynamics ◽  
Dynamics Model ◽  
Model Formulation ◽  
Flight Dynamics Model

Trajectory Simulations for Laser-Launched Microsatellites Using a 7-DOF Flight Dynamics Model

2009 ◽  
Author(s):  
David A. Kenoyer ◽  
Kurt S. Anderson ◽  
Leik N. Myrabo
Keyword(s):  
Laser Beam ◽  
Specific Impulse ◽  
Flight Dynamics ◽  
Basic Research ◽  
Scale Model ◽  
Beam Power ◽  
Small Scale ◽  
Dynamics Model ◽  
Predictive Tool ◽  
Flight Dynamics Model

Laser launch trajectories are being developed for boosting nano- and micro-satellite sized payloads (i.e., 1 to 100 kg) using a 7-Degree Of Freedom (DOF) flight dynamics model that has been extensively calibrated against 16 actual trajectories of small scale model lightcraft flown at White Sands Missile Range, NM on a 10 kW pulsed CO2 laser called PLVTS. The full system 7-DOF model is comprised of individual aerodynamics, engine, laser beam propagation, variable vehicle inertia, reaction controls system, and dynamics models, integrated to represent all major phenomena in a consistent framework. The suborbital trajectory results presented herein are for a 240 cm diameter lightcraft (100 kg payload; 100 MW beam power) flown under three different laser-boost scenarios: 1) liftoff and vertical climb-out on a vertically oriented laser beam; 2) liftoff and climb-out along a constant laser beam pointing angle (fixed azimuth and zenith) defined relative to the launch pad; 3) liftoff and climb-out on a beam with a time-varying pointing schedule (azimuth and zenith) to “slingshot” the lightcraft laterally, making maximum use of the engine’s autonomous beam-riding feature. For simplicity, simulations assume a solid ablative rocket propellant (e.g., Teflon®-like performance) with a vacuum specific impulse of 644 seconds, momentum coupling coefficient of 190 N/MW, and overall efficiency of 60%. This flight dynamics model and associated 7-DOF code provide a physics-based predictive tool for basic research investigations into laser launched lightcraft for suborbital and orbital missions. An investigative protocol was developed to identify and quantify phenomena that dominate each phase of the launch trajectory. These protocols are specified herein, along with physics-based explanations for such phenomena, both predicted and observed.

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