Mathematical Model Of Combat Aircraft Sizing & Performance Optimization [TL671.2. P276 2007 f rb].

Tesis ini menerangkan tentang permodelan matematik anggaran berat, prestasi dan pengoptimuman rekabentuk jet pejuang pada tahap konsep awal berasaskan pelbagai kaedah. Model ini dihasilkan khas bagi merekabentuk kapal terbang berinjin kembar yang supersonik untuk operasi “hi-lo-hi”. This thesis gives thorough analysis on the mathematical model of combat aircraft sizing, performance and optimization for initial conceptual design stage, based on various fighter design methodology. The developed mathematical model is specifically for designing a supersonic fighter of twin engine aircraft where the design mission of this fighter is hi-lo-hi operation

Modelling of solar irradiance and daylight duration for solar-powered UAV sizing

Solar energy from the sun is the largest available renewable energy that enhances the endurance of a solar powered unmanned aerial vehicle. However, harnessing this solar power is a great challenge. This is due to having solar module system’s power output efficiency of only about 15–30%. However, a solar powered unmanned aerial vehicle has the potential to outperform a battery only operated unmanned aerial vehicle, especially when task being a pseudo satellite which requires long operating hours. The atmospheric conditions and geological locations undoubtedly the main cause for poor performance of these solar modules. In spite of its prolific improvement in solar cell efficiency over the years, the overall solar module system barely converts half of sun’s power into electricity. Therefore, this situation makes the current system unattractive to be widely used for energy harvesting. Recent attention has been focused not only on type of solar cells but on its positioning system. However, there were lack of understanding and research on the solar irradiance intensity and daylight duration’s effect on the power output. Therefore, a comprehensive model was developed to study on how the sun movement affects the solar module system’s performance. This simulation model has identified the daylight duration is more important in comparison to the available solar irradiance. Moreover, the higher the solar irradiance and daylight duration, the solar module system gives the most power output. The daylight duration also depends on the latitude where the higher the latitude gets, the longer the daylight duration. Besides, the longitudinal coordinates and elevation have minor effect on the daylight duration estimation. In other words, in summer, the northern hemisphere has more advantage compared to the southern hemisphere locations and vice versa

Development of design methodology for a small solar-powered unmanned aerial vehicle

Existing mathematical design models for small solar-powered electric unmanned aerial vehicles (UAVs) only focus on mass, performance, and aerodynamic analyses. Presently, UAV designs have low endurance. The current study aims to improve the shortcomings of existing UAV design models. Three new design aspects (i.e., electric propulsion, sensitivity, and trend analysis), three improved design properties (i.e., mass, aerodynamics, and mission profile), and a design feature (i.e., solar irradiance) are incorporated to enhance the existing small solar UAV design model. A design validation experiment established that the use of the proposed mathematical design model may at least improve power consumption-to-take-off mass ratio by 25% than that of previously designed UAVs. UAVs powered by solar (solar and battery) and nonsolar (battery-only) energy were also compared, showing that nonsolar UAVs can generally carry more payloads at a particular time and place than solar UAVs with sufficient endurance requirement. The investigation also identified that the payload results in the highest effect on the maximum take-off weight, followed by the battery, structure, and propulsion weight with the three new design aspects (i.e., electric propulsion, sensitivity, and trend analysis) for sizing consideration to optimize UAV designs

Experimental Study of Solar Module & Maximum Power Point Tracking System under Controlled Temperature Conditions

An experimental work has been designed to evaluate the performance of solar module thoroughly. This is crucial to develop a solar module and maximum power point tracker (MPPT) system design for optimal operation of solar-powered unmanned aerial vehicle (UAV). The impact of temperature and solar irradiance intensity at various solar module angle investigated to study the effect of solar module power output of a moving UAV. Moreover, the effect of lamination on solar module and the benefit of MPPT for application of small solar-powered UAV are scrutinized. The results show that the optimum operating temperature for this solar module is approximately 45°C and solar power rises almost linearly along the solar module tilt angle. The laminated solar module has consistently loss 10% power compared to the non-laminated solar module. Besides, an additional 24% power can be obtained with the use of MPPT for small solar-powered UAV developed by Aircraft Design Group, Cranfield University

Sensitivity analysis of design parameters of a small solar-powered electric unmanned aerial vehicle

The design, fabrication, and operation costs of a solar-powered unmanned aerial vehicle (SUAV) only comprise a small fraction of the various aspects of satellite systems. Given the easy redeployment of SUAVs with a newly enhanced payload, many researchers have become interested in studying the potential of SUAVs as pseudo-satellites. However, research on the capability of a small SUAV to achieve year-round global perpetual operation remains in its infancy. The endurance of small SUAVs may be further improved by reducing system weight and power consumption. Therefore, sensitivity analyses are performed to determine the effects of payload, propulsion’s weight to power ratio, and solar module’s weight to area ratio on the weight and power consumption of a small SUAV. The outcome of this investigation is vital to avoid unnecessary investment on product development that may not significantly improve the performance and capabilities of SUAVs. The payload exerts the greatest effect on the maximum take-off weight of a SUAV, followed by the battery, structure, solar module, and propulsion weight. The weight to area ratio of the solar module should be prioritized in technological advancements to promote the endurance of SUAVs. In addition, small SUAVs will considerably benefit from improvements in the weight to power ratio of the propulsion

Experimental Assessment of Various Batteries and Propellers for Small Solar-Powered Unmanned Aerial Vehicle

In this study, the performance of the propulsion system of a solar-powered unmanned aerial vehicle (UAV) was investigated. Both battery and propeller variation tests were performed to evaluate their performance in relation to an electric motor. The battery was varied in the number of cells and capacity, and the propeller was varied in terms of diameter, pitch, manufacturer, and propeller type (fixed and folding propellers). For validation, the bench test result was compared with a simulation model. The bench test provided a reasonable guide for the throttle level required to obtain optimal power. A large variation existed in propeller performance between manufacturers. Sizing electric propulsion is important for UAV performance and the manufacturing factor is significant for propeller performance

Combined effect of nozzle pressure ratio and screech prone supersonic mach number in a suddenly expanded flow

This paper presents the results of an experimental study to evaluate the effectiveness of the micro jets to control the base pressure in a suddenly expanded flow at supersonic Mach numbers. Four micro jets of 1mm orifice diameter located at 90 intervals along a pitch circle diameter of 1.3 times the nozzle exit diameter in the base region were employed as active controls. The Mach numbers of the present study were 1.8 and 2.0. The jets were expanded suddenly into an axi-symmetric circular tube with cross-sectional area 2.56, 3.24, 4.84 and 6.25 times that of the nozzle exit area. The Length to Diameter ratio of the suddenly expanded duct was varied from 10 to 1 and experiment were conducted for Nozzle Pressure Ratio (NPR) from 3 to 11. Jets were over, under, and correctly expanded depending upon the NPR of the respective runs. When flow from the nozzle was over expanded or under expanded an oblique shock or expansion fan will be positioned at the nozzle lip, which in turn will result in increase or decrease of the base pressure. From the results it was observed that at NPRs 3 the control was not effective, however, at NPR 5, 7, 9, and 11 a significant change in the base pressure for all the area ratios was seen. From the results it was concluded that the level of expansion, Mach number, length-to-diameter ratio, and area ratio played an important role to fix the value of the base pressure and the control effectiveness by the micro jets

An effective proportional-double derivative-linear quadratic regulator controller for quadcopter attitude and altitude control

A quadcopter control system is a fundamentally difficult and challenging problem because its dynamics modelling is highly nonlinear, especially after accounting for the complicated aerodynamic effects. Plus, its variables are highly interdependent and coupled in nature. There are six controllers studied and analysed in this work which are (1) Proportional–Integral–Derivative (PID), (2) Proportional-Derivative (PD), (3) Linear Quadratic Regulator (LQR), (4) Proportional-Linear Quadratic Regulator (P-LQR), (5) Proportional-Derivative-Linear Quadratic Regulator (PD-LQR) and lastly (6) the proposed controller named Proportional-Double Derivative-Linear Quadratic Regulator (PD2-LQR) controller. The altitude control and attitude stabilization of the quadcopter have been investigated using MATLAB/Simulink software. The mathematical model of the quadcopter using the Newton–Euler approach is applied to these controllers has illuminated the attitude (i.e. pitch, yaw, and roll) and altitude motions of the quadcopter. The simulation results of the proposed PD2-LQR controller have been compared with the PD, PID, LQR, P-LQR, and PD-LQR controllers. The findings elucidated that the proposed PD2-LQR controller significantly improves the performance of the control system in almost all responses. Hence, the proposed PD2-LQR controller can be applied as an alternative controller of all four motions in quadcopters

Experimental analysis of small solar ummanned aerial vehicle to predict aerodynamic performance

Various studies have been done in recent years on unmanned solar-powered aircraft for non-stop flight at a specified location or area. However, if a solar-powered unmanned aerial vehicle (UAV)can achieve a non-stop flight around the world, it may lead to the possibility of a pseudolite (i.e., pseudo-satellite) operation. These solar UAVs capable of operating as a satellite enable sustainable aviationthat provides cheaper communication accessibility. Recently, we have developed a mathematical model for solar UAVs that was followed by the fabrication of a solar UAV model. Both the mathematical design model and the prototype model have been published. Thus, this work aims to determine the actual flight performance characteristics of the fabricated solar UAV. In this work, the bench and flight tests of the prototype solar and non-solar UAV model were compared in terms of aerodynamic characteristics and performance. These characteristics are determined using the flight test data and then compared with simulation data using a mathematical design model published earlier. Both accelerated and un-accelerated methods have been applied to predict the polar drag curve, and a distinct band of data obtained for both UAV prototypes. The predicted zero-lift drag coefficients were similar to the theoretical prediction in these UAV

Power Management Strategy by Enhancing the Mission Profile Configuration of Solar-Powered Aircraft

Solar energy offers solar-powered unmanned aerial vehicle (UAV) the possibility of unlimited endurance. Some researchers have developed techniques to achieve perpetual flight by maximizing the power from the sun and by flying in accordance with its azimuth angles. However, flying in a path that follows the sun consumes more energy to sustain level flight. This study optimizes the overall power ratio by adopting the mission profile configuration of optimal solar energy exploitation. Extensive simulation is conducted to optimize and restructure the mission profile phases of UAV and to determine the optimal phase definition of the start, ascent, and descent periods, thereby maximizing the energy from the sun. In addition, a vertical cylindrical flight trajectory instead of maximizing the solar inclination angle has been adopted. This approach improves the net power ratio by 30.84% compared with other techniques. As a result, the battery weight may be massively reduced by 75.23%. In conclusion, the proposed mission profile configuration with the optimal power ratio of the trajectory of the path planning effectively prolongs UAV operation