Integrating Mission, Aerodynamic–Structural Sizing, and Additive Manufacturing Constraints in the Conceptual Design of a Modular UAV

Conceptual design of small UAVs intended for tactical ISR missions is often complicated by the disconnect between early-stage aerodynamic/mission sizing and the manufacturability and field-deployment constraints that emerge later in the design cycle. This work presents an additive-first conceptual design framework that embeds those constraints from the outset. Mission-driven sizing equations based on Raymer and Sadrey are coupled with a parametric OpenVSP model, while the sizing loop is constrained by practical limits imposed by low-cost fabrication: maximum printable part dimensions, PLA’s orientation-dependent stiffness, integration of carbon-tube spars, internal placement of thin subsystems, like servos, cables, and connectors, and the detachable interfaces required for hand-launch and backpackable operation. These constraints directly affect the admissible geometry, structural layout, and mass distribution and are therefore treated as first-order design drivers rather than downstream corrections.

Structural feasibility is evaluated through finite element analysis of printed PLA components and PLA–carbon hybrid substructures, providing stiffness and failure predictions that inform the conceptual iterations. A prototype vehicle is fabricated to assess deviations between analytical, numerical, and as-built characteristics, with emphasis on structural margins, assembly tolerances, and the practical penalties introduced by modularity. Results show that including printability and field-handling constraints at the conceptual stage leads to materially different optima in wing loading, aspect ratio, and internal structural layout when compared to traditional unconstrained sizing. By integrating mission analysis, aerodynamic estimation, and manufacturability into a unified early-stage process, the framework offers a fast, practical approach for the preliminary design of low-cost, rapidly deployable UAV systems.