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Unmanned aerial vehicles (UAV) are used in the military field for missions such as observation, surveillance and seeking object. UAV observation can be used to monitor humans, weather, forests, agriculture, and fisheries and so on. UAV can be operated for very broad missions with low development costs compared to manned aerial vehicles with a low risk of death. The design of an aircraft affects the performances of the aircraft itself. Aircraft flying characteristics are influenced by the value of coefficient of drag (CD) and coefficient of lift (CL). The value of CD affects how much aircraft friction with the air, while the value of CL affects how much lifting force the aircraft is produced so it can fly. The design output needs the most optimal CD and CL values to get the optimal aircraft performance. In this study, we simulated the effect of 4 digit NACA changes on the characteristics of the plane's CD and CL. This study uses variations modification of NACA digits with different variables. NACA airfoil 4 digit series (MPXX) designates camber lines, maximum camber position and thickness. Based on the results of this study, the optimal CD and CL values for the Airfoil NACA with the Aerosonde UAV model are designs that have a large ratio of lift and drag (CL / CD). The lower the CD value and the higher the CL value, the better the performance of the UAV. The design that has the largest CL / CD is the NACA 6412 Airfoil. [ABSTRACT FROM AUTHOR]

Water tunnel (WaTu) visualization techniques have been in high demand to analyze aerodynamic characters in the delta-aircraft model because of clearer and more detailed results. The visualization was used to observe the aerodynamic characteristic of the rolled-up vortex phenomenon on delta-wing. The difference in fluid and flow parameters became an issue of the accuracy of the results. Therefore, testing parameters need to be analyzed so that the results of the WaTu test have been able to represent the real conditions. This research has varied the velocity to investigate the delta-wing aerodynamic characteristics using GAMA water tunnel. The results were compared with computational fluid dynamics (CFD) results based on WaTu and real (subsonic) conditions, as well as several other references. The results showed a similarity in the vortex breakdown location (VBL) at all flow rates in the WaTu and CFD. The CFD results also showed that the coefficient of pressure (Cp) on the wing had the same results in all tests, both based on WaTu and real conditions. Likewise, for a lift and drag coefficient (Cl-Cd), values for all states approached the same amount with a difference of less than 5%. Finally, the uses of the WaTu method has been able to represent the actual conditions in vortex dynamics cases in delta aircraft with the optimum velocity to produce the best visualization around 0.1 m/s. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicle is a type of aircraft that has a very wide application. In this study, numerical calculations were performed using ANSYS Fluent software to find the effects caused by the implementation of the area rule theory to the fuselage of a surveillance Unmanned Aerial Vehicle (UAV). The area rule theory usually used on the transonic aircraft while the surveillance UAV is a very low speed aircraft. The study was conducted by varying four prototype of UAV fuselage with different volume distributions on the area around the wing without varying other part such as wing, tail, etc. The study was conducted using the k-omega SST viscous model (k-ω SST) with the mission profile having a distance of 200 km, a ceiling of 500 m, and a speed of 20.8333 m/s. Mesh is made of polyhedral with a very good standard of skewness quality and mesh orthogonal quality. The results of this study indicate that the implementation of the area rule theory to the fuselage of a surveillance UAV didn't affect the drag force that occur on the aircraft, but the implementation of the theory increased the lift force occur on the aircraft, although it's not significant. [ABSTRACT FROM AUTHOR]