Aluminum Aero Modelism Airfoil

Can an empty soda can become an aircraft wing? This project sets out to answer exactly that question. By combining a recycled aluminum can with a compliant 3D-printed airfoil rib, the naturally springy materials are coaxed into forming a smooth aerodynamic profile. Rather than aiming for a finished product, this is intentionally a proof-of-concept prototype, a first attempt to discover what works, what doesn't, and what unexpected challenges emerge. If this prototype proves one thing, it is that sometimes the best way to find out whether you can is to start with a can.

1. One (or more) empty soda can (I am using a 330ml can but you can adapt the concept to any size)
2. Scissors and or a utility knife
3. 3D printer
4. If you want to design your own wing profiles: Inkscape (free software)+Freecad

The top and bottom of a soda can are responsible for most of its structural rigidity. Their domed shape acts as a reinforcement, making the can surprisingly resistant to crushing and deformation. For this project, however, that stiffness is undesirable. By carefully removing both ends, only the thin cylindrical wall remains. Without its reinforced caps, the aluminum body becomes remarkably flexible and spring-like, allowing it to be elastically reshaped into an airfoil by the internal 3D-printed rib.

To prepare the can, begin by scoring around the top and bottom with a sharp utility knife. Once an opening has been made, switch to scissors to complete the cut. Using both tools provides a cleaner, more controlled cut while reducing the risk of tearing the thin aluminum. The result is a lightweight cylindrical shell that is ready to be transformed into the wing skin.

This step is divided into two parts. In the first video, you will learn how to design the basic rib profile in Inkscape. This way, you can create your own airfoil or experiment with different shapes, there is one important design rule: the outer profile of the rib must remain convex. The thin aluminum skin can easily bend outward to follow a convex curve, but it cannot naturally conform to concave sections without wrinkling or buckling.

Another key aspect of the design is the rib's perimeter. The total length of the outer profile should be slightly larger than the inside circumference of the soda can. This intentional oversizing creates a preload: the rib must be compressed slightly to fit inside the can, and once released, its spring action pushes outward against the aluminum shell, forcing it to adopt the desired aerodynamic shape. The circumference of your can can be calculated from its diameter using:

Perimeter = π × Diameter

For the best results, design the rib so that its perimeter is just a few millimeters longer than the can's circumference. Too little interference will not provide enough pressure to shape the skin, while too much may cause the aluminum to wrinkle or make assembly difficult.

In the second video, the 2D profile created in Inkscape is imported into a CAD program (I used FreeCAD) and transformed into a printable 3D model. This is also where the compliant spring sections are added. These springs allow the rib to compress during insertion into the can and then expand, applying a nearly uniform pressure against the aluminum skin. The rigid leading and trailing edges preserve the airfoil geometry, while the flexible central section provides the elastic force needed to hold the skin in shape.

Assembly is surprisingly straightforward.

Begin by creating a sharp fold along the aluminum can skin where the trailing edge of the wing will be. This fold serves two purposes. First, it helps the thin aluminum naturally conform to the airfoil shape by introducing the tight bend required at the trailing edge. Second, it acts as a convenient alignment feature: both ribs share this same fold as a reference, making it easy to position them consistently along the span of the wing.

Once the fold has been made, gently compress one of the 3D-printed ribs and insert it into the cylindrical aluminum shell. As the rib expands, its compliant spring sections press outward against the inside of the can, forcing the aluminum to adopt the airfoil profile. Repeat the process with the second rib, using the folded trailing edge to align both ribs with one another.

With both ribs in place, the aluminum skin is held under slight tension, producing a smooth aerodynamic surface without the need for adhesives or fasteners. The entire assembly relies on the elastic interaction between the spring-loaded ribs and the recycled aluminum skin, making for a remarkably simple yet effective construction.