In the past few years, the usage of Unmanned Aerial Vehicles (UAVs) aircraft has increased significantly, but the need for UAVs with higher performance is increasing also. Therefore, all systems of the UAVs must be developed to have high efficiency, including the propulsion system. It is necessary to perform some design and analysis tasks on low Reynolds number propeller, which is a commonly used propulsion system on UAVs, to have higher efficiency and improve the overall UAVs performance. In this paper, low Reynolds number propellers are designed using the Larrabee Design analytical method by referring to the “Master AirScrew 10x7E” propeller. Meanwhile, performance of the designed propellers is analysed by using analytical method of Inversing Larrabee Design method. At the design stage of low Reynolds number propeller, 42 variations of alpha design (αdes ) was inputted along the blades with uniform, linear, and quadratic distributions. Furthermore, the best design from these 42 variations was selected by performing two-stage scoring. At first stage scoring, 42 designs are selected to obtain 5 designs with the highest on-design efficiency. Then, performance of these 5 selected designs are analysed analytically along a certain range of advance ratio. Finally, second stage scoring is performed to obtain 1 design with the best overall performance.

Aeroelastic phenomena including divergence and flutter are investigated for composite plate wing without sweep angle. Suitable derivations of aerodynamic loads have been developed for calculating both flutter speed (U F) and divergence speed (U D). Equivalent plate method is used for structural modeling of composite plate wing. Approximate solutions from the linearized formulation are obtained for studying steady and unsteady aerodynamic loadings on harmonically oscillating wing in subsonic flow. The wing is divided into element panels on which lift distributions are represented by concentrated lift forces. The pressure coefficient distribution is calculated at root chord using steady and unsteady aerodynamic modeling. The span wise distribution of lift coefficient is calculated from the pressure coefficient. The numerical results for both U F and U D show good agreement with previous works. Finally a parametric study of the effect of composite fiber's orientation on both U F and U D is carried out.

The aeroelastic characteristics of wing depend upon the relationship between its aerodynamic and structural properties of the wing box. In the present work the wing box structure has been modeled using linear equivalent plate approach. The mass and stiffness matrices are calculated for a wing composed of skin, spars, and ribs based on simple polynomial functions. The static and dynamic responses to external loads are calculated for a short plate, and a wing box. The doublet point method has been used for calculating the effect of unsteady aerodynamic loads on harmonically oscillating wing in subsonic flow. Using the standard eigenvalue methodology, the solutions for the resulting complex eigenvalue problem are obtained. The V-g method has been used for determining the flutter speed of rectangle wing by calculating the natural frequencies and damping ratios. The obtained results show good agreement with published results. A parametric study has been carried out to obtain the effect of changing the thickness of skin on the flutter speed. The influence of the aspect ratio on the wing flutter speed has been shown that the flutter speed decreases when the aspect ratio increases.