Aero Metro by JoshuaChance 001

[ChazInMT]

I can't help myself....

Droodle droodle

[joshuachance]

@ChazInMT

Interesting that there is an 'aero template'.

Thanks for the pics with it already averlayed on a metro (even the right body for my year).

Where does this template come from? It has been hard for me to find the more 'meat and potatoes' reseach on things like laminar flow (wich it looks like is the intention here). Granted, my own contributions so far are mearly like a garnish or salad dressing... ha ha, I love analogies...

But seriously... um, I have thought about a larger plate in the very back, so that these arches are not as dramatic on my car. Actually I increased the plate already on my 2011 version a little. Only about 2 inches on both the height and width of the back plate. Not much...

It is difficult, i'm sure for many, to want to stray away from something shorter and eventually end up with a compact car longer than a small bus.

Also, anything about the trailing edge mods to sever that laminar flow without creating so much vacuum?

Mostly, any citation to some good research on this 'aero template' would be great!
Also, what are the reasons for keeping the lower portion of the template so close to the ground? Is that due to the benefits of a lower profile to help eliminate the turbid flow from all the landscape underneith the vehicle?

Yet another relm for me to think about now. Ha ha, I love it!

Thanks again,
JoshuaChance

[ChazInMT]

Lotsa good back & forth in this thread, in the end I concluded we were both right, flow separation occurs at 23° no matter the placement of the template, however, in order to achieve low Cd aero dynamics, you need to put the template under the wheels. Just cause the flow is attached, does not make it efficient. My theory is a lift drag is created by a too aggressive drop like your proposed boat tail and my 1st gen aero cap. I think the air needs to "build in under pressure" in the back of the vehicle to avoid a dynamically produced low pressure. Don’t worry about a larger "flat spot", you are much better off following the template.

http://ecomodder.com/forum/showthrea...onds-2104.html

Here is the thread with a lot on the template as well.

http://ecomodder.com/forum/showthrea...rt-c-9287.html

And here's where I get the % data from:

http://ecomodder.com/forum/showthrea...tml#post217655

This thread puts to numbers the fact that if you chop off the tail of the ideal aero shape, you really don’t pay a huge penalty for it until you get to around 20-30%.

Hope this serves as some meat & taters for you, I know that this website over the last year and a half has brought me a long ways towards better understanding this stuff.

[joshuachance]

@ChazInMT

Excellent!! Thank you very much...

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"I think the air needs to "build in under pressure" the back of the vehicle to avoid a dynamically produced low pressure."
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This is something i've been thinking about a lot sitting in my garage tonight (enjoying a few frosty beverages).

I mean, when the very tail end of the 'tail' is tapering off from both the top and bottom, and also both sides... I think there may be too great of an area where the air is all trying to fill the tapered empty spotsand then create too much low pressure...

Just a quick thought. But something to consider. Thaks!

JoshuaChance

[joshuachance]

Sorry... don't wanna go off on too much of a tangent maybe more appropriate for another thread...

@some other dave

Yes, totally see all the campaign signs around... they just took them all down here a month ago...

So, I stopped by a couple of the local 'sign stores' here this week the see if they had corrugated plastic I could buy from them. It was harder than I expected! Many didn't have it in larger sizes, and the ones that had 4' x 8' sheets wouldn't sell it as stock. They wanted $100+ for them with the condition that they printed on it themselves.

I found a few sources on tha interwebs that sold 4' x 8' sheets, but they want $20 to $30 a sheet (depending on thickness), and required a minimum of 10 sheets per order... no doubt I could use ten sheets at some point for some project... but 300 bucks all at once in hard to choke down.

I think the campaign signs will be hard to glue all together, but kinda considering it at the moment. Maybe if I swing by one of the sign places and see them face to face, they may reconsider based on the 'cool' project I am attempting. Wishfull thinking, ha ha.

Thanks again
JoshuaChance

[lunarhighway]

did some aero metro sketches a while back, so just for fun here they are

[hotrodfeguy]

Ok if someone could Pic 3 from the top does anyone have some real world measurments of what that would be from the rear trunk mount? I know these are concept drwings. But were these done by a areo template? Any input anyone?

The reason I ask is I am looking at seriously making a 2 seater for areo. And everything from the point of the drivers seat pillar roof line back is something I am willing to play with. If you Areo gurus can give me measurements of optimal effect I can do the hardware sort of speak on a first gen Metro 89-94

[aerohead]

A 20% increase from a single mod is tasty fun!
If you were starting from Cd 0.32,the tail,according to your new mpg should have dropped you to Cd 0.192 or thereabouts.
So the air thinks you're driving a scaled down EV1.Sweet!
Thanks for the doing and the sharing.I'm already breathing easier.

[hotrodfeguy]

I am more than willing to crank up the welder and do this just need measurments for the first gen metro tail.

[freebeard]

Ok if someone could Pic 3 from the top does anyone have some real world measurments of what that would be from the rear trunk mount?

It sounds like you may be talking about lunarhighway's post, but isn't the third one the bobtail?

With 2 posts in 2 days, you seem motivated. What are you going to be welding? Tubes? Sheets?

Maybe someone who *has* a first gen Metro could help, which dimensions do you require?

lunarhighway's designs don't follow The Template, but that's not necessarily a bad thing. See the GM EV-1.