Aero Fenders are precision, laser-cut front and rear fenders for standard pinewood derby cars. The fenders improve air flow over the wheels resulting in a few milliseconds of advantage. Both front and rear fenders are available, and are typically used together.
Aero Fenders are available in both pine and balsa wood, and are 3/8 inch thick. Both types have a spacer to maintain clearance from the track guiderail.
Pine fenders come in two parts, the main fender and the spacer. Balsa is lighter in weight, but not as strong as pine. So, to improve strength, the Balsa fenders are machined in three layers (one layer is a spacer). After gluing the three layers together, they are quite strong.
Pine Fender Pair(1): Front - 3.1g, Rear - 3.8g
Balsa Fender Pair(1): Front - 1.3g, Rear - 2.1g
(1)Estimated weight assuming typical shaping.
Aero Fender Instructions
Glue the two (or three) parts of a fender using yellow (wood) or white glue. Use a clamp or masking tape to hold the parts together until the glue is fully dry.
Make sure to create a left and right fender - the fenders will be mirror images of each other. The smaller piece (spacer) goes on the inside of the fender with the open area downward.
Mark the desired curvature on top of the fenders. Next shape the curves and do as much presanding as possible. Beveling and shaping is easiest with a power sander, but it can be done by hand. In the photo, I did not shape the curves on the front fenders as I will do that once they are glued onto the car. (see next photo).
Temporarily mount a wheel on the car, then test fit the fender. Mark the fender location with a pencil. Remove the wheel, glue the fender in place with yellow (wood) or white glue, and clamp until the glue is dry. The bottom of the spacer should be aligned with the bottom of the car.
Repeat for the other fender on the same side of the car. When the glue dries, repeat the process for the other side of the car.