Development of a Lightweight Fixed-Wing Drone for Early Situational Awareness in Critical Applications

Abstract

This thesis explores the development of a lightweight, sub-250 g fixed-wing drone intended for early situational awareness in emergency response scenarios. Conducted in collaboration with Remote.aero and the Swedish Sea Rescue Society, the work focuses on concept development, aerodynamic optimization, prototyping and validation through flight testing. An extensive benchmarking study identified key design parameters and trade-offs for tailless UAVs. Utilizing XFLR5 aerodynamic simulations, the study optimized critical design variables, notably aspect ratio, taper ratio and wing span, to maximize the L/D ratio within the intended flight envelope. Two prototypes were constructed using 3D printing, confirming theoretical predictions and demonstrating competitive performance during flight tests. The final prototype achieved a stall speed below 8 m/s, a maximum estimated endurance of approximately 43 minutes at loiter speed of 10 m/s, and a maximum estimated range of 55 km at a cruise speed of 25 m/s. The maximum L/D ratio was 16, at a loiter speed of 11 m/s. Its low intrinsic ground risk classification (iGRC 1) under current regulations simplifies deployment in both urban and rural settings, allowing it to compete with heavier systems while offering critical regulatory advantages. However, flight testing revealed that the reduced mass of the drone makes it sensitive to wind gusts, limiting reliable flight at wind speeds exceeding approximately 10 m/s unless additional airspeed margins are maintained. Ultimately, the design met all other requirements and could carry out a typical mission profile with ease, fulfilling the purpose of the project