Wing Box Covering

One of the tasks that we recently completed was the covering of the wing box, the central section between the two wing coverings. Though not crucial to putting the plane in the air, this covering certainly improves the aerodynamics of the plane, as well as the overall appearance.

Both of the wing coverings had Velcro pre-sewn onto the open edges, so I decided to use this by sewing a covering that wraps around the front and velcroes on to the top and bottom. We decided to use 2.97 oz Dacron, which is lighter than the 4 oz fabric used on the wings, and UV-resistant thread. Though we initially experimented with adhesive-backed Velcro, we found that this was much more difficult to sew compared to the regular Velcro.

As for the design, I started by mapping out the overall layout on construction paper and holding it up to the plane to ensure a taut fit. I then made a test covering with actual Dacron fabric before moving on to the final piece. I cut the fabric using a soldering iron with flattened blades. This was intended to prevent fraying, but I tried to sew most of the seams anyways.

The final piece starts at the top front edge of the tail boom, wraps around the leading edge of the wings, and ends at the bottom edge of the tail boom. This design requires us to temporarily remove the keel tube to assemble. In the areas where cut-outs were required to make space for tubing, I sewed on flaps so that wind will not get caught in these open areas.

The Dacron piece covers the open space between the two wings, and is held on using Velcro.

The fabric was cut using a soldering iron with a modified tip. The heat melted the fabric to prevent fraying.

I periodically did fit checks and pinned the piece to the plane to ensure that I got rid of any slack and that the piece conformed well to the contours of the plane.

I used a sewing machine for all of the sewing, which resulted in a cleaner, stronger finish. I also layered the fabric when I sewed to ensure greater strength.

The covering wraps around the leading edge, requiring us to remove the keel tube.

In this perspective view, you can see that the covering generally follows the shape of the wings on either side.