Design of Structure and Control System for a Small-Scale Fixed Wing UAV

Aerodynamic experimentation is often done with wind tunnel testing, which can be expensive. There are many programs to perform aerodynamic analysis via simulation; however, physical testing may shed light on some problems not covered by simulation. Our small-scale UAV is meant for physical testing of new aerodynamic concepts such as the use of flaperons, unique airfoil shapes, or the outboard horizontal stabilizer on a tailplane.

Our design is meant for rapid prototyping and modularity. It is innovative because it uses a non-conventional 3D printing material called Light Weight PLA (LW-PLA) along with other materials to ensure our plane is as light and strong as possible and can be manufactured quickly. Along with LW-PLA, we use a conventional RC airplane material, balsa wood, as a supporting structure due to its high strength to weight ratio. Finally, we use a carbon fiber rod that connects the tail to the fuselage. Our design is meant to be modular so that the plane can be assembled and disassembled easily, with the possibility to swap out wing and tail shapes.

Our design has been carefully researched and has undergone extensive analysis by simulating the aerodynamics, analyzing the propulsion system, completing strength calculations, and analyzing the control system. With the software XFLR5, the preliminary aerodynamic analysis was completed. This gave us lift and drag coefficients, target speeds, and a target weight for our aircraft given the wing shape. Another software, MotoCalc, was used to determine flight performance using different combinations of marketed propellers and motors. Using the simulated results from XFLR5, an appropriate propulsion system was selected for the achievable flight characteristics. For further validation of our design, CFD has been completed. SolidWorks was used to model the aircraft where the center of gravity was calculated and strategically placed. Moments of inertia were calculated from the 3D model which allowed us to appropriately size our control surfaces and select servo with the required torque.

Our design solution is entirely feasible and is projected to cost less than the allotted budget of $500. The plane can be manufactured with any 3D printer, and the remaining materials are accessible through local hobby shops.