I’ve made some parts for Peter Borenstadt’s DF for his Battle Mountain runs in the past. This year we’re going to try a few new tweaks. First, I’ve made a slimmed down version of my DF race hood by reducing the top and sides of the current version. Here are some photos of the effort.

Peter also wanted to improve the air flow through the cockpit, hoping that it may reduce overall drag of the DF and perhaps reduce CO2 levels in the cockpit. One way of doing this is to drill several large holes in the trailing edge of the DF. However that’s difficult with the tail extension coming to a point. He suggested adding a vent to the derailleur cover to see if that makes a difference. Here’s what I came up with:

It seems to allow air flow through the opening without messing up the air flow of the surrounding tail surface. We still won’t know if it actually makes a difference until Peter has a chance to test it.

Probably the last piece that I’ll make is a new tail extension. The goal here is to improve on the existing tail extension by adding a piece to fair in the trailing edge of the rear tire. In the past, we tried a rear wheel fairing but that seemed to unsettle the DF’s rear end at high speed. Rather than build a new rear wheel fairing, he thought that it might be worth trying to extend the tail extension lower and forward to at least fair the trailing edge of the rear tire. While we are at it, we thought we’d remove the concave curved area on the top of the tail fairing and shape it to continue the DF’s rear hump.

Here’s a bad Photoshop rendering of the proposed changes to the tail fairing.