More Tinkering on the DF XL

Since retiring, I’ve been having fun designing and building new pieces for my DF XL. Here’s a little update on these designs.


The idea here is to be able to use the race cap (hood) more often to boost my speed. Up until now, I could only use the race cap on very cold days due to the heat and steam that builds up inside. Adding a new air inlet in the form of a NACA duct to the front access panel should help solve that problem. It definitely moves a lot of air so it succeeds on that goal. Now I need to do some roll down tests to see if the extra drag created by the duct offsets the benefit of running with the race cap. It might turn out to hurt more than it helps. I’ve posted more details here…

Zefal Spin Mirror covers

I decided to go back to the very small stock Zefal Spin mirrors. I never liked the way they looked. I also thought that their aerodynamics could be improved. At the urging of PeterB on BROL, I designed this little mirror cover using Fusion 360. I doubt that it will make any difference at the speeds that I travel ( ~20 – 25mph most of the time), but I think they look a little more finished.

ABS Plastic Heel Bump Guards

I first saw these on my former Milan GT. Then I saw that Ben Dover on BROL had put these on his DF. The heel bumps are the first things to scrape going up driveways. They’re compound shapes so making a guard from flat ABS plastic sheet is a bit tricky. So I took some measurements of the heel bumps and shaped this mold from some rigid foam. This allowed me to heat up the ABS sheet and press it into shape.

4 thoughts on “More Tinkering on the DF XL

    • Keep in mind that most of the commercially available NACA ducts are designed to mount on a flat surface. You’ll end up having to modify yours to fit the extreme curves of the DF’s panel

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