UAV Span Morphing Wing: Structural Design and Flight Envelope Assessment

June 24, 2026

The morphing approach intends to extend an aircraft’s flight envelope to allow flight at different conditions with no efficiency loss. The variable span wing allows an aerodynamic efficiency increase by adjusting the aspect ratio to the flight phase. This work establishes a structure, endowing it with variable span. For that, the pre-project by Silveira (2019) was adopted, defining the airfoil and the variable span. Changes were defined for the pre-existing wing, after which the aerodynamic loads were assessed with CFD for the flight envelope extreme points. These loads were imported into the structural module for a finite element analysis, where the structural reactions were assessed. From this work, a cruise airspeed of 59 m/s was obtained for the extended wing and 70 m/s for the retracted wing. The stall speeds are 30.85 m/s and 38.11 m/s respectively. The dive speeds are 88.5 m/s and 105 m/s respectively. These airspeeds represent an increase relatively to those defined by Silveira (2019), for both configurations. The results show the extended wing withstands the stresses at all flight envelope points. However, the retracted wing fails at the PLAA point, since the highest stresses happen at the epoxy-carbon component, exceeding the limit stresses. The wing withstands the other points. To make the retracted wing withstand the PLAA point, the mobile skin must be made of Aluminium 2024-T3, whose limits are higher than the stresses found. Making the mobile skin in the this alloy will bring the wing mass from 50 kg to 54.5 kg.

Authors in the community:

• 

  P

  Pedro Miguel da Costa Folgada

  ist176055

Supervisors of this institution:

• 

  F

  Filipe Szolnoky Ramos Pinto Cunha

  ist14018

mechanical-engineering - Mechanical engineering

eng - English

Instituto Superior Técnico