  This paper presents the first design of a soft, 3D-printed in flexible
filament, lightweight UAV, capable of performing full-body perching using soft
tendons, specifically landing and stabilizing on pipelines and irregular
surfaces without the need for an auxiliary system. The flexibility of the UAV
can be controlled during the additive manufacturing process by adjusting the
infill rate distribution. However, the increase in flexibility implies
difficulties in controlling the UAV, as well as structural, aerodynamic, and
aeroelastic effects. This article provides insight into the dynamics of the
system and validates the flyability of the vehicle for densities as low as 6%.
Within this range, quasi-static arm deformations can be considered, thus the
autopilot is fed back through a static arm deflection model. At lower
densities, strong non-linear elastic dynamics appear, which translates to
complex modeling, and it is suggested to switch to data-based approaches.
