# Design, Manufacturing, and Flight Testing of an Experimental Flying Wing UAV
## 1 Introduction  
The development of unmanned aerial vehicles (UAVs) has attracted much attention in the aviation industry for decades, especially in the United States. [PERSON] [1] noted that the current UAV market is predominantly driven by military requirements. The mainly military applications of UAVs include reconnaissance, transport, and search and rescue. This study noted that operational costs, safety, and multirole capabilities are the dominant factors driving civilian UAV applications. A report from the US Department of Defense (DoD) addressed some significant technologies needed for various UAVs [2]. These technologies can be supported by the current state-of-the-art technology. As the US DoD develops the more multi-functional UAVs, other countries are following the same strategic rules and are developing or purchasing such systems. The current state-of-the-art technology provides low-cost and high-performance sensors, communication, navigation, guidance, and control. For example, Pixhawk 4 (or Ardupilot) is a common and low-cost flight control and navigation system hardware for civilian, research, or hobbyist use. It consists of an inertial measurement unit (IMU) (gyroscopes and accelerometers), magnetometer (compass), barometer, global positioning system (GPS) module, power system, and interfaces. Its powerful autopilot software can handle all flight control and navigation requirements of the UAV. Low-cost UAVs have a significant influence on the overall value and specific applications in the aviation industry. Aerodynamic design plays a crucial role in an aircraft's conceptual design. An aerodynamic design layout strongly influences the aircraft's structures and systems, and in turn, its manufacturing process. Good aerodynamic design enables an aircraft to have good performance and reduces costs via lower fuel consumption. At the start of the aircraft's conceptual design, many parameters mustbe determined. Studies have developed aircraft conceptual design methodologies for conventional aircrafts [3,4] and analyzed various techniques for this purpose [5]. [PERSON] developed the matching of sizing aircraft performance methods for subsonic aircrafts [6]. Hydrocarbon fuels such as petroleum are used most commonly in aircrafts. Therefore, the development of conventional design methodologies is based on hydrocarbon fuels [3, 4, 5]. Flight duration depends on the energy carried by the UAV. The energy density of petroleum, lithium-ion batteries, and lead-acid batteries are 46.4, 0.36-0.88, and 0.17 MJ/kg, respectively. High-energy-density fuels enable lower weights and better performance under the same flight conditions. Therefore, the use of low-energy-density fuels in aircraft design is a research challenge. Further, the weight strongly influences the aircraft's power consumption, making it challenging to design a battery that can satisfy the aircraft's required range and endurance. [PERSON] developed a methodology for sizing the electric propulsion subsystems of UAVs [7]. An electric-powered UAV is heavier than a petroleum UAV in all scenarios. If the energy density of batteries is increased in the future, electric-powered UAVs with reduced battery weight and improved performance can be realized. With improvements in avionics devices such as the battery and electric motors, electric-powered UAVs have attracted increasing research attention. Recently, [PERSON] derived equations for evaluating the range and endurance of electrical aircrafts [8]. This study considered the effects of [PERSON]'s law on the battery discharge process to provide a better concept for battery weight design. Later, [PERSON] presented a simple example for determining the correct values of the best range conditions [9]. Flight test methods were developed for a small, electric-powered flying wing UAV [10]. This study successfully found the drag polar and various performance parameters including the range, endurance, climb performance, and turn performance for electric-powered flying wing UAVs.