Here's the design I came up with:
Here's how that might look:
So is it a roof spoiler? partial kammback? boxed cavity? partial boxed cavity?
Sorry but if it's going to be permanent then aesthetics are at least somewhat pertinent for me.
Even at that small of a size, a guarantee you that I'll get sticky notes stuck to my windshield at least once a week saying "Sweet spoiler, broh!!" I live in a college down (Lawrence, KS) and park near the football stadium to go to work every day, and yesterday someone stuck a sticky note to the windshield saying "broh! nice roof rack bro!" and I'm still scratching my head wondering if they were laughing at my expense or genuinely complementing my welding skills or somewhere in between.
If it was the size of this kammback then people would be shouting out their windows at me daily:
http://ecomodder.com/forum/showthrea...-6-a-6069.html
^^^ That's a good thread, btw. Although he never says how long it is, but it looks like 18" to 24" to me. So maybe twice the length of the one I designed, but it goes all the way to the bumper.
However, the bottom is not closed off. Which flies in the face of this quote from aerohead:
Quote:
Originally Posted by aerohead
Your cardboard mockup is more like a box-cavity,and for it to work,it needs to be as low as the bottom of your bumpers bottom,and it needs a 'floor'.It cannot be open on the bottom unless there is a back on it,and the back is airtight.
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(I really hate photobucket, btw)
That quote is from this thread -
http://ecomodder.com/forum/showthrea...k-29583-4.html - in which a fellow SUV ecomodder tries a cardboard kammback/boxed cavity, and sees only a 1% increase in MPG over stock and after several days worth of testing.
So, given all these things, can I realistically expect maybe 1/3 the results that MetroMPG got with that minivan? Which would be a little over 1% so I would go from 15 mpg to 15.15 mpg which is insignificant IMO.
Still though I will try and test it. Today the scan tool is supposed to arrive in the mail, but conveniently I broke my iphone last night! Which it needs to connect to. I could use my fiance's maybe, idk.
(don't mind me, I'm just going to continue dumping my brain out into this post)
You see these roof spoilers on every new hatchback and SUV being made today and they seem to be getting longer and some are even going over the sides too.
So I guess that's what I'm going for.
BTW, that last one is the 2017 Lexus RX. I found this:
How the new 2016 Lexus RX cheats the wind - Lexus
And this:
Novel Spoiler Design Reduces Fuel Consumption for Minivans, SUVs - Green Car Congress
Quote:
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A team of researchers has used the principles of fluid dynamics and numerical simulation to design a new rear spoiler for bluff-backed vehicles (such as minivans and SUVs) that can reduce drag and lift [...] by 5% and more than 100%, respectively, when the new spoiler is attached to it.
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Are there any vehicle in production using a spoiler like this?
Is 5% a lot?
If I take this data...
...and ignore the "1.9d" part and follow Mair's assumption that it's a function of the width not the length, then I get this:
And that shows that I can get the same 5% reduction in bluff body drag with only 5 inches of "partial boxed cavity" as I call it.
Yeah I know I'm speculating big time. Mainly that a partial boat tail has the same aero benifit as the "partial boxed cavity" that I'm talking about.