The 2-Part Aero-Body Concept

[kach22i]

Originally Posted by aerohead

*It is the pressure gradient from the max camber point aft which is critical to the streamlining......... I recommended Hoerner

That's what I thought, but the front (Zones 1 & 2) ability to funnel air to the rear so that it stays attached should have a importance factor or something assigned to it. Something like 25% front, 75% rear importance ratios?



I gotta get a look at them books soon.

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Neil, yes I've seen that one it comes off like a Dick Tracy car, like a 1930's vision of the future. I'm not a huge fan of it, but see the beauty of it's intent if not it's aesthetic execution. I'm hoping to pull off something a little more timeless yet modern.

[aerohead]

Originally Posted by kach22i

That's what I thought, but the front (Zones 1 & 2) ability to funnel air to the rear so that it stays attached should have a importance factor or something assigned to it. Something like 25% front, 75% rear importance ratios?



I gotta get a look at them books soon.

.................................................. ....................

Neil, yes I've seen that one it comes off like a Dick Tracy car, like a 1930's vision of the future. I'm not a huge fan of it, but see the beauty of it's intent if not it's aesthetic execution. I'm hoping to pull off something a little more timeless yet modern.

Hucho would say that the front of the car has been unimportant since the debut of the 1st-gen VW Rabbit/Golf in the 1970s.
In the 'Flow-Images thread you can see this car in VW's climatic wind tunnel.Hucho himself was part of the streamlining optimization team responsible for the final production design.
Any automobile that has at least as much leading edge radius as the Rabbit is 'good to go' as far as aft-body streamlining.
A JEEP of this time period would not qualify,just as its offspring(Wrangler) or HUMMER H-1 would not today.
But for automobiles,it's a done deal,especially when you consider that all of today's pickups and SUVs have lower drag coefficients than Corvette did when the Rabbit first went on sale.
The back of a cars body is good for a 300% drag reduction.
The front is good for about 58%.

[kach22i]

Originally Posted by aerohead

The back of a cars body is good for a 300% drag reduction.
The front is good for about 58%.

That's roughly a 1:5 ratio, right?

Thanks for the information once again.

http://s184.photobucket.com/albums/x...ransportation/
Was

TODAY'S CHANGES

[NeilBlanchard]

George,

Can you post your latest sketch without the template overlay, or just use the one full scale template overlaid on the whole car? Your design has 2 aerodynamic parts, but it's the rear fenders that are the second part; not the greenhouse and roof. This is because the fenders are going to cause the air to push outward for a second time. This is a departure from the template, and there will be some "interplay" between the air flow around the roof which has begun it's return to where it was, and the fenders will re-compress the air locally to the raised fender.

Also, the rear wheel track could be narrowed and this could gain a lot lower drag.

[kach22i]

Originally Posted by NeilBlanchard

Can you post your latest sketch without the template overlay.....the (rear) fenders are going to cause the air to push outward for a second time. .... will re-compress the air locally to the raised fender. .

The original base sketch has been undergoing some of the mark-ups in my ACDSee photo program. This has the green on it already. However, I'll do one big overlay over the whole thing.

The two schemes above differ in the way the rear fenders interact, and it is this "compression" of air and the flow which I'm playing with in my head. The former is very illuminati motor works-seven looking as Neil (you) pointed out earlier. The later is a return to the Mooncraft racing car approach.

The Mooncraft approach may actually cause more of a squeeze on the rear quarter air passage, but I'm currently debating that assumption between me, myself and I. I might go mad before I figure it out.

Industrial Design - Transportation pictures by kach22i - Photobucket

[kach22i]

This is at least the 5th version of the 1.5 model, so I'll calling it the 1.5 Mk-5.

Industrial Design - Transportation pictures by kach22i - Photobucket
Mk-5

Mk-6


As much as I like the Mooncraft race car, I've been trying my best to find my own voice. And besides, the rear wheel humps following that concept might cause some compression of the flow over the top deck between the canopy and hump (as Neil pointed out).

I'll be drawing up some perspectives pretty soon on this, really should have done that sooner. Later I hope to model this in clay.

EDIT: Mk-6 has even simpler lines.

[TEiN]

I really like the Mk-6. Clean, simple, racy.

[kach22i]

A few more schemes, also went back to the sketch I did over the GrabCad contest template.
http://s184.photobucket.com/albums/x...ransportation/




Comparative overlay"

[Sporty Modder]

I really like the straight sides of mk6 combined with mk8 overall look.

[kach22i]

Originally Posted by Sporty Modder

I really like the straight sides of mk6 combined with mk8 overall look.

I can illustrate that in several ways.

Industrial Design - Transportation pictures by kach22i - Photobucket


It's not working for me, fails at an aesthetic level (stepped on tail), and at a functional (aerodynamic) level.

The air should be able to fall off the belt-line shoulder and cascade at a downward angle, in my opinion.


EDIT: This holds promise.



Race car up front, aerodynamic car from the 1930's in the back. Gotta keep working on this one.