Another Ranger aero bed topper, (with ???) - Page 4 - Fuel Economy, Hypermiling, EcoModding News and Forum

thx138 · 01-05-2014, 05:43 PM

I like the idea of the areo caps. I also see that a 12 degree downslope towards the rear is beneficial. On all of the ones I have seen drawings for and some of the very nice ones people have built, using the 12 degrees (roughly) from the cab height means that there are varying degrees of height required above the tailgate to maintain the 12 degrees. What if I was to take the 12 degrees and start at the tailgate to then come forward. I mocked this up and on my ranger I would be about half-way up the rear window. The benefit to this approach is that the rearview mirror is still useable. The question is, is there the same benefit in areo? Instead of one larger trailing edge, I would have two, which in total height would be the same as a single one, but it would break the airflow twice instead of once. (is this a bad thing).

Thanks

Xist · 01-05-2014, 07:25 PM

Something like the red line?

Thx138, my understanding is that there is always benefit from "filling the wake," but you would still generate drag on the entire area outside of the aero topper.

I think that if you simply made a flat topper at the proper height for air to reattach at your tailgate, you would have some visibility, reduced wake, and reattached air, I just do not know how beneficial it would be.

freebeard · 01-05-2014, 08:09 PM

I went back and re-read the thread. I still like the idea of incorporating a Dodge Magnum rear hatch. It's sort of perfect.

I think of the flat 12° topper as a compromise with buildability. The tough problem is the bed doesn't have taper in plan.

Maybe a flat-sided, simple-curved topper with a notch only wide enough to to accommodate the sight-line? See if you can move the mirror up into the windshield header and gain anything.