Problem

We faced the challenge of designing an electric RC aircraft for the 2024-25 AIAA Design/Build/Fly competition that could excel in two conflicting mission profiles: a captive carry flight carrying external fuel tanks/payload (Mission 2) and an autonomous launch of an X-1 test vehicle (Mission 3). The primary technical challenges included managing the aerodynamic interference and significant drag penalty from the external payload while maintaining stable flight characteristics, optimizing the aircraft to perform efficiently both with and without payload weight, and ensuring the aircraft could achieve reliable takeoff distances across vastly different weight configurations. Additionally, the design needed to balance performance with affordability (a scored metric) while meeting all handling quality requirements for safe, repeatable flights.

Figure 1 - CAD Model of the Aircraft design in Solidworks

Solution

As Lead Aerodynamics Engineer, I led a comprehensive aerodynamic optimization effort addressing the unique challenges of the competition missions. Using SolidWorks Flow Simulation, I conducted CFD analysis on the nose cone and fuselage to minimize frontal drag and identify optimal contours for smooth airflow attachment. A critical challenge was analyzing the aerodynamic interference effects of the captive carry configuration. The external payload created significant parasitic drag and altered the airflow over the wing. Through iterative simulations, I determined optimal mounting locations that minimized flow separation and drag penalties while maintaining structural load paths.

Using XFLR5, I performed extensive wing design analysis and stability calculations across multiple loading conditions. I faced the challenge of sizing the wing to provide sufficient lift for the heavy captive carry mission while avoiding excessive drag during the lighter autonomous launch mission. Through first principles calculations and iterative analysis, I determined the optimal wing area, aspect ratio, and airfoil selection that balanced these requirements. I conducted static and dynamic stability analysis to ensure positive stability margins across the full center-of-gravity range, which shifted significantly between missions.

Another key challenge was ensuring the aircraft could meet takeoff distance requirements across both mission profiles. I performed takeoff calculations accounting for varying gross weights, drag coefficients, and thrust available, iterating the wing design until both missions met requirements with adequate safety margins. The aerodynamic design was then manufactured using precision balsa wood construction techniques for the wing and tail structures, integrating carbon fiber spars to handle the increased loads from the captive carry mission while maintaining the optimized aerodynamic profiles.

Figure 2 - CFD Simulation of the nose cone

Skills Used

SolidWorks and SolidWorks Flow Simulation were used for 3D modeling and CFD analysis of the fuselage, nose cone, and payload interference effects
XFLR5 was used for airfoil selection, wing planform optimization, and longitudinal/lateral stability analysis across multiple loading configurations
First principles aerodynamics and flight mechanics were applied to calculate lift-to-drag ratios, takeoff performance, and stability derivatives
Excel/MATLAB were used for performance trade studies and mission analysis calculations
Hands-on manufacturing techniques including precision balsa wood fabrication, carbon fiber spar integration, and composite layup