AeroWagen

[botsapper]

70's sports-wagon concepts, contradiction of terms but GM did coupe conversion studies inspired by the 1955-57 Chevy Nomad/Pontiac Safari wagons. A classic Kammback-template

http://flymall.org/blog/wp-content/u.../01/Slide8.jpg

http://assets.blog.hemmings.com/wp-c...DN619-0278.jpg

http://flymall.org/blog/wp-content/u.../01/Slide4.jpg

https://s-media-cache-ak0.pinimg.com...b209a4e69e.jpg

http://pics.imcdb.org/0is715/transamktype001.5559.jpg

1986-90 Nissan Pulsar NX Sportsback in interchangeable. http://4.bp.blogspot.com/-J74CFGfn7U...tY/s1600/1.jpg

[Fingie]

The top is good if you are a high-stakes dealer and have to outrace some cops :P

[freebeard]

Originally Posted by Stubby79

Too bad it doesn't transform a cheap car in to a good looking one. Don't think I'd wanna mess up a real 'vette.

But Corvettes are cheap. In their class.

Originally Posted by ibid

It's too shallow, imo.

The roofline appears unaltered to the B-pillar. So frontal area is unchanged. The shooting brake roofline has a reverse camber that will allow reattachment of incipient separation.

[kach22i]

Originally Posted by freebeard

The roofline appears unaltered to the B-pillar. So frontal area is unchanged. The shooting brake roofline has a reverse camber that will allow reattachment of incipient separation.

He has a valid observation, we just need to find the proper language for it.

Frontal area is similar to cross-sectional area, yes?

What is the area at the stern called, the hole in the air which is leftover?

Isn't that called the "virtual tail area" or something like that?

Area of a "truncated foil"?

But the car is not a perfect foil, the tangent lines can be all over the place, and in a 3D vortex generator style of differing pressures, not strictly a 2D sectional observation without termination ends (wing tips).

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On a boat this area might be called a "transom board area".

http://newboatbuilders.com/pages/hp.html


Although, if we were talking non-planing hulls, it would be the area below the waterline at the stern/transom that we would be most concerned with, right?

Again, my earlier argument was that the vectors or direction of the air leaving the end of the car is just as important as the rear area it's self.

Extreme examples are a too steep of a fastback, and flat across semi-truck trailer without aero-devices attached.

[aerohead]

Originally Posted by kach22i

Interesting points, lots to think about. The whole in the air the body leaves is important, but so are the air vectors releasing from the body.

Would the Corvette be part of the Bluff Body family? It certainly is not teardrop shaped beyond the canopy.

Some of the reoccurring issues we have in the forum is that only the side view gets compared to the template, no part of the top view is included, and little other 3D analysis.

I could do a template overlay on the stock and AeroWagen version, and include both side profile and top views, I could even attempt to toss in a cross section at the 3/4 mark.

However I'm not convinced it would prove much, and that full scale testing is the only alternative when splitting hairs as fine as this.

EDIT:
The difference between "b" and "c" is a surprise to me.

Alfa img - Showing > Lift Coefficient of Shapes


There is a chart floating around the forum which shows Bluff Body lengths or perhaps Semi-Truck lengths with small differences in relation to Cd. If I stumble across it in the next few days I will post it here.

The drag coefficients presented are dubious and not representative of actual drag coefficients.
I suspect that they're deleting skin friction and presenting only pressure drag,as Mair did in his boat-tail research.
No.I finally caught it.These are volumetric-based Cds from fuselage,airship, and submarine hull research.
There also surface-area-based Cds.
We need frontal area-based Cds.
No 3-D streamline body of revolution can have a frontal-area-based Cd below 0.04,in free flight,away from ground effect.

[freebeard]

These are volumetric-based Cds from fuselage,airship, and submarine hull research.

Still of interest to me because... submarine/motorhome.

But (a) has a diameter 1 2/5ths that of (b-f). According to my brass caliper, they are within the line width of each other, but then the lengths vary .......aaaah!

Here's where it comes from: https://www.nmri.go.jp/eng/khirata/fish/

[aerohead]

The longer hulls suffer increased skin friction,and have frontal area-based Cd 0.07.
The short,'Tin Bubble' at bottom is optimized for pressure/friction drag,with Cd 0.04.

The reason 'short' hulls aren't produced is do to limited payload,directional stability issues,and air-sickness for the crews.And as a camera or weapons platform it would be virtually impossible to hit a target with the ship listing,yawing, and pitching all over the place.

[freebeard]

https://en.wikipedia.org/wiki/Russian_monitor_Novgorod

Novgorod (Russian: Новгород) was a monitor built for the Imperial Russian Navy in the 1870s. She was one of the most unusual warships ever constructed, and still survives in popular naval myth as one of the worst warships ever built. A more balanced assessment shows that she was relatively effective in her designed role as a coast-defence ship. The hull was circular to reduce draught while allowing the ship to carry much more armour and a heavier armament than other ships of the same size.

T'weren't no Yankee Clipper.

[kach22i]

Originally Posted by aerohead

.......The reason 'short' hulls aren't produced is do to limited payload,directional stability issues,and air-sickness for the crews.........

Originally Posted by freebeard

Russian_monitor_Novgorod......

T'weren't no Yankee Clipper.

Early hovercraft were omni-directional; often round or equilateral triangle in plan.

Despite hovercraft having no direct contact with the ground (in theory), the short shapes suffered the same ills of round boats and short blimps.

Extremely short wheel based cars be they the 4-wheel or 3-wheel variety suffer the same fate of instability.

I imagine that there are exceptions to the rule, but it's what I have been able to derive from my readings.

[freebeard]

According to the Wikipedia article the Novgorod spun down a river and out to sea so violently were everyone was dizzy. I'm skeptical.

But it would make a great steampunk UFO.