The 2-Part Aero-Body Concept

[kach22i]

Regarding curved edges;

Originally Posted by ERTW

............. a radius on all the vertical surfaces that's >10% of the thickness (of the base) will do more for you than fences.

What is the base thickness?

The 27 vertical inches of the side, or the six foot width of the body?

Going with the first one, 2.7" radius is more curved than many cars out there.

The second number is around a 7 inch radius, so I don't think it's that, seems a bit much.
.................................................. .

I can feel (seat of the pants) aero-treatments on my truck in the 30-35 mph range. I'm a big fan of down-force, too many examples of aero-looking cars requiring rear spoilers (ie Audi TT) to stay on the road to think it is not a real world issue.

[euromodder]

Make the front a bit bulbous in plan view, radius the straight edges, boattail & cover the rear wheels and ditch the wing.

[kach22i]

Originally Posted by euromodder

Make the front a bit bulbous in plan view, radius the straight edges, boattail & cover the rear wheels and ditch the wing.

A concise summary, thanks.

Started working on some of those things, other things started but not quite there yet.

Industrial Design - Transportation pictures by kach22i - Photobucket

[NeilBlanchard]

Race cars are not low drag -- let me rephrase that: *most* race cars are not low drag.

The straight sides with no taper on any side will be high drag. Here's the lowest drag race car I know of:




It's the Le Mans Panhard 64.

[kach22i]

Originally Posted by NeilBlanchard

Race cars are not low drag -- let me rephrase that: *most* race cars are not low drag.

True, but you can also take a kit car loosely based on The Ford GT 40 (Factory Five GTM), add in some West Philly high school students, plus a Volkswagen TDI engine running on 100% biodiesel, and get over 100 mpg (read 160 mpg somewhere) and win the Green Grand Prix.

Factory Five GTM Wins Green Grand Prix
Factory Five GTM Wins Green Grand Prix

How West Philly Students Built a Hybrid Supercar
How West Philly Students Built a Hybrid Supercar - Breakthrough Awards 2011 - Popular Mechanics 2011 - Popular Mechanics

The students from West Philadelphia High School didn't win the X-Prize competition, but their 160 mpg Factory Five GTM biodiesel hybrid kit car is a Popular Mechanics Breakthrough Award winner.

Proving; just because it looks like a race car, doesn't mean it's a brick.

I have a long way to go with this concept before it is that refined. I'm just saying, don't live by stereotypes because there are exceptions to the rules.

[NeilBlanchard]

I've seen the West Philly High School cars in person and I've chatted with several of the students who helps build it. This was in June 2010 at the Michigan Speedway for the X-Prize Knockout Round.




They used the chassis because they were available. I think the 160MPGe must be electric only. I know that the Ford Focus (their other car) at least used a Harley engine -- a sentimental favorite, but hardly capable of mileage even above 50MPG.

Since you are looking to build a from scratch chassis, why not go for all the efficiency you can? Aero drag is a huge contributor to energy loss, and it is a total loss, always.

[kach22i]

Originally Posted by NeilBlanchard

Since you are looking to build a from scratch chassis, why not go for all the efficiency you can? Aero drag is a huge contributor to energy loss, and it is a total loss, always.

I didn't mean this so much to be a "design" as a "concept" intended to express the idea of combining "two parts".

It is a format to learn by, explore and maybe a leaping point. I have much prettier cars, this is just a test mule.

One test is the rear, and to see if what I did works and why. If it works (wing aside), can it, should it be done to other cars with benefit?

Examples below of applying this principal to other cars. The goal is not to make them prettier, but to aid in lowering drag. I know they have "stuff" back there (like an engine), just taking "form" here. Is this form, serving a function?

Automobile 2 - Odds and Ends pictures by kach22i - Photobucket

Automobile 2 - Odds and Ends pictures by kach22i - Photobucket


Industrial Design - Transportation pictures by kach22i - Photobucket


Couple More.........
http://s184.photobucket.com/albums/x...%20and%20Ends/

[NeilBlanchard]

I think that by leaving the two rear wheel fenders as large and square (all are flat and a couple are rising) then there will be two fairly large turbulent wakes instead of one larger one. Plan taper and top taper would do more to reduce wake drag than the channel in the middle, I think.

Ignoring the exhaust system, you can't beat this rear end:





Here's one closer to what you may be going for?

[kach22i]

Originally Posted by NeilBlanchard

I think that by leaving the two rear wheel fenders as large and square (all are flat and a couple are rising) then there will be two fairly large turbulent wakes instead of one larger one. Plan taper and top taper would do more to reduce wake drag than the channel in the middle, I think.

I did study putting a taper in plan, some studies included the top and sides too. However these subtle details just were not going to make the study concept model, as did not rake fences, chin spoilers and other refinements. I might have a study drawing buried somewhere of a more 3D solution, when I clean up I'll scan that one too.

This model and drawings are like a lump of clay to me, and need to be cut into and developed (and smoothed out).

It is not an end, it is a start.

A start to repositioning myself mentally from a One-Part concept, to a Two-Part concept. The fact that it may resemble a "race car" is happenstance in some respects (not an intended outcome). However I cannot deny making a mental connection to some old slot cars I had as a kid. Once the design ball got started rolling, it was off to the races.

Industrial Design - Transportation pictures by kach22i - Photobucket



I think the concept may look like a race car because it is solving a similar problem (packaging wise), therefore the outcome is similar.

Originally Posted by NeilBlanchard

........... and a couple are rising)

A couple of planes are rising?

Where?

The underbelly/diffuser?

EDIT....I'll lose my train of though before I find the other old sketches. So I did a mark-up to recapture the eventual refinements I had/have in mind.



The same types of refinements to the front, will be good for aero, and it should make for a prettier car as well.

[drmiller100]

On neil's pics, everything is waaaay too steep at the back to be aero.

20 degrees to the central axis is about max, regardless of hopes and wishes.