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Old 08-01-2013, 07:56 PM   #7 (permalink)
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Originally Posted by coltonandrew View Post
Ahh good point. Spending x amount of money on some plexi glass doesnt seem too worth it either.

We always drive with the windows down as well, so I wouldn't be too worried about carbon monoxide.

Regardless of, it's not a risk I'd like to take.

So then theoretically speaking; would propping the rear hatch open work for mpg gains on the highway or would the potential vacuum deem the idea detrimental to mpg?
The lowest pressure on the ASTRO is around the windshield/A-pillar area.
If you have wind-wing, vent windows,opening them subjects the inside of the van to this low pressure.If the vent windows are open,it will bring air in from wherever it can get it,including the tail.It could be nasty.
The hatch itself would not be able to do the pressure recovery as an entire tail section would.And its own downwash (if flow remained attached to it) might actually aggravate the homogenous wake you already have.
If you could prop the hatch open,but close it in on sides and bottom with some surrounding rigid envelope you'd have you a boat tail.
With some rudimentary powertools you could fab up a crude wooded skeleton with 1/8"mahagony door skin,skin ,drywall screws and house paint to integrate into the opened hatch,or replace it.It would be enough to test.'
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