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Old 02-01-2013, 09:45 AM   #5 (permalink)
EcoModding Lurker
Join Date: Jun 2011
Location: Austin, TX
Posts: 74

Annette - '04 Ford F150 FX4

Penelope - '08 Mazda CX-7 Sport
90 day: 23.47 mpg (US)
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Video mirrors are ideal, however they're just illegal in too many places. I do so much interstate travel (I'll be in Tennessee, Indiana and Pennsylvania just in the next two weeks) and I'm bound to pass through one of those areas where they write tickets for that, or having too dark tint, or etc.

On the upside, the work I'm planning to do, and what I have in mind would benefit those who can use video cameras as well as mirrors.

My idea came from watching the airflow in wind tunnel videos. Normally, the air that hits the window comes from over the hood, 1/4 of the way in to the center line. As it comes around the windshield, it drops down at a 10-15 angle. Since drag increases as a square of the speed, tuning the headlight for 50-70 mph seems far better than any lower speed where it has a near negligible effect, relatively speaking.

I have this notion of a triangle of fiberglass or carbon fiber or 3D printed ABS that picks up the air as it comes around the A pillar and lets it take a more gentle curve, coming just 3" or 4" out of the side of the vehicle. The curve would be optimal for the 10-15 airflow. This would give a nice 6" tall by 3-4" wide mirror in close to the vehicle that has about 1/2 to1/3 the frontal area, but to the wind has maybe 1/6 to 1/4 the area.

I need to do some testing on the idea because I know it will have some trailing turbulence and putting it that close to the window may create a comfort issue. That said, with my aerocap on, the most obvious wind noise is from my mirrors anyway.

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