Uav-paper

Aerodynamic Modeling of UAV Project for the Peruvian Air Force

The development of UAV systems over the past three decades has been consistent and considerably helpful in many areas such as military Intel operations, surveillance, scientific research, mining, industrial fishing, agricultural Industry, etc. Both military and the civilian world have benefited from the multiple uses a UAV system can be given. The Peruvian Government realized the necessity of developing its own UAV system, reason why the Center of Development of Projects (CEDEP) of the Peruvian Air Force (FAP) is developing the first Peruvian UAV system, with the support of the National Council of Science, Technology, and Technological Innovation (CONCYTEC). This paper summarizes the aerodynamic modeling of the first prototype of the project.

The aerodynamic modeling of the prototype went through the following phases: Conceptual Design and sketch of the design, 2-D Airfoil and Finite Wing Analysis, Design Analysis, and flight test of the first prototype based on the final design.

The conceptual design was based on the requirements for the prototype. The prototype will be a medium range, long endurance surveillance UAV for both military and civilian purposes. Following this line, the prototype has a conventional design for a long endurance aircraft, with a propeller pusher piston engine. The prototype is capable of carrying a specified payload, and will be an autonomous aircraft managed from a ground station. The autopilot uses GPS technology.

Figure 1: Fuselage Design

The Design Airfoil software was used to perform the 2-D Airfoil and Finite Wing Analysis. The software allows you to explore any kind of four, five and six digit NACA airfoils by giving you its corresponding aerodynamic coefficients. A NACA Airfoil was chosen for the prototype’s wing as it was best suited to accomplish the mission requirements. The Wing Span (b) and consequently wing size area (S) were chosen by our engineers following conventional design rules for this type of aircraft and recommendations from our aircraft manufacturer, who has over fifteen (15) years of experience building aero model aircraft.

The next step was to calculate the Stability and Control coefficients. The Advanced Aircraft Analysis (AAA) software provides these coefficients by inputting the geometry of the designed aircraft, flight conditions, and piston engine parameters in the software. These stability and Control coefficients were used to program the autopilot software, MICROPILOT, which is currently being used to fly the Pegasus prototype. As example, figure 2 below shows the lift coefficient vs. angle of attack and figure 3 shows the coefficient of drag derivative with respect to change in angle of attack versus the angle of attack.

Figure 2: CL vs. Angle of Attack (α)

Figure 3: Drag coefficient due to change in angle of attack vs. Angle of Attack

Finally, the AEROPAK visualization software allowed our engineers to find mistakes in the geometric design of the aircraft. If mistakes were found, they were corrected and an iterative process begun back to the AAA software to re-calculate the stability and Control coefficients until the results satisfied both stability and control of the aircraft and a smooth and appropriate design, concluding the design analysis phase.

Figure 4: View of the Pegasus prototype from AEROPAK

The prototype was built and flight tested to discover any problem in performance of the aircraft due to the design and or incorrect stability and control parameters. The aircraft presented no problems during flight testing, allowing us to confirm the FAP has its first successful flying UAV system prototype. The project is currently flying its

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