3D Printed Plane · Ethan Kong

Why a modular wing

I designed this 1.8 m fixed-wing plane with travel to Malaysia in mind. A one-piece wing would be awkward to print, pack, and carry, so I split the airframe into sections. That made the joints part of the design from the start: each section has to align when assembled, while the main structural path still needs to carry loads across the span.

This was my first time designing a 3D-printed wing. The CAD work taught me that reducing print material is only useful if the structure left behind can still support the wing.

Red and blue printed plane sections, wing panels, fuselage, and tail laid out during assembly — Printed airframe sections during assembly. The separate panels made the plane easier to build and pack for travel.

Fusion 360 rendering of the modular wing assembly with open bays and section joints — The wing assembly in CAD. Separate panels and open bays reduce printed material and make the span easier to transport.

What the wing taught me

The open bays in the printed panels remove material that a solid print would use. The spar matters more than simply adding plastic back: the spar provides a continuous path for the wing’s bending loads, while the printed structure defines the airfoil shape and transfers loads into that path. The panel joints also need to keep the sections aligned without becoming unnecessarily heavy.

Close-up CAD rendering of a 3D-printed wing panel showing lightening bays and the edge joint — A closer look at the cutouts and the panel edge. The geometry is a weight-saving iteration, not a measured structural result.

What happened in the first build

Without a spar, the wing deflected substantially. That flexibility contributed to unstable behavior and made clear that lightening the printed panels could not substitute for a continuous bending member. The video records an early hand-launch trial, not a structural measurement.

Early hand-launch trial. The experience exposed the need for a spar and a stiffer, better-aligned wing assembly.

I also saw instability around the tail in the pusher-prop configuration. I would revisit the center of gravity, static margin, tail size, and propeller flow before attributing that behavior to any one component. For the next iteration, I would establish a spar route first, measure wing stiffness with the sections assembled, and then remove material around the verified load path.