The 2-Part Aero-Body Concept

[kach22i]

Before I seek out the books and start locking in my thinkings (both a good and bad thing), one more scaling of the template study.

Proper:


Scaled to fit:


No-template:

[aerohead]

Originally Posted by kach22i

Before I seek out the books and start locking in my thinkings (both a good and bad thing), one more scaling of the template study.

Proper:


Scaled to fit:


No-template:

The only way for the 'Template' to work is to use it exactly as depicted.
The x,y,z,vector coordinates of the aft-body surface elements are based on the full height of the vehicle contour.
Changing the scale as shown for the canopy alters the pressure gradient which is protecting the boundary layer and preventing separation.

[kach22i]

Originally Posted by aerohead

The only way for the 'Template' to work is to use it exactly as depicted.
The x,y,z,vector coordinates of the aft-body surface elements are based on the full height of the vehicle contour.
Changing the scale as shown for the canopy alters the pressure gradient which is protecting the boundary layer and preventing separation.

Using the reasoning above, one could then argue that Zone-1 and Zone-2 pressure zones illustrated below, destroy any chance of Zone-3 working at all, even though it conforms to the template.

Automobile 2 - Odds and Ends pictures by kach22i - Photobucket


Also using this reasoning, there is not a car or truck out there which can benefit even a little bit by attempting to make one part or another (typically the aft section) template friendly.

I cannot accept this as an all or nothing, black or white proposition. What has everyone in the forum been doing with all of their efforts then? And what of all the results and success stories?

And what of Zone-4?
http://s184.photobucket.com/albums/x...%20and%20Ends/


I did a little more work on the "1.5 body" last night, scanned and did the overlays this morning. I do want to bring it "all together" in the end.
http://s184.photobucket.com/albums/x...ransportation/

[Sven7]

George, it's not that the thing won't work-it might- it's just that it won't work optimally. You may have nice, attached flow, but that doesn't mean you didn't leave more aero gains on the drawing table, so to speak. Putting a boat tail on an existing car helps its aero, but still has areas to improve upon. No production car is perfect in this respect, so if you're going to start from scratch why not use the template properly?

[kach22i]

Originally Posted by Sven7

George, it's not that the thing won't work-it might- it's just that it won't work optimally... so if you're going to start from scratch why not use the template properly?

Tyler; optimal aerodynamics as you know may leave the driver crash prone between the front wheels (wide car), or with the windshield four feet ahead of the drivers eyes, which may cause a Pontiac TransVan type driver disorientation of being unable to judge distances.

Neil's five seater solves some of these concerns with a center driver's position, but there may be other solutions too.
http://neilblanchard.blogspot.com/20...ct-part-3.html


If we can answer the 4-Zone question (see the Insight), not only will it help me develop my own design, but I think could provide insight to other projects and designs.

It's about the journey, not so much an end result with only one right answer.

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

[Sven7]

Crash zones aside, you can throw templates and 18* angles over everything but the kitchen sink, however if they're not applied right you won't get a quality product. You need to use the template correctly if you're using it at all. That means the ground plane has to be at the ground plane.

Looking forward-
Instead of confining yourself to these parameters, why not think laterally?

How about building on the GM Ultralite Concept's design.

It already has a bulbous front and tapered rear.



It also has a curious front bumper.



What I'm suggesting is a Schlorwagen type passenger compartment which trails the front axle. Then for crash protection put an airfoil across between each front wheel pod. This would direct crash energy out sideways to the pods instead of back to the passengers.

No, it's not the ideal situation but there is also no free lunch. A properly designed airfoil should leave the air reasonably undisturbed when it contacts the main body shell. It also gives you an opportunity to do some interesting styling stuff. Notice I cut off the back of the template to integrate a bumper. This is both to conform to at least some regulations and to look nice.

Here, a sketch


The real problem with this kind of thing is that you're wasting all the space ahead of the template. This is why cars like the EV1 and Insight do not follow the front of the template. It's a packaging disaster for a production car.

[Sven7]

It might need some vents at the rear of the wheel pods just before they reach the main body, but you'd need to aero test it to make sure.

This is just a rough Alias model and I took some liberties with the wheel arches and stuff, but it's built to the template in profile. The rear end taper is a template teardrop scaled to full width, with the zero degree mark over the rear axle.

The dimensions except for length are based on a 90's Honda Accord. After all, it's hard to design a short aero car.

[kach22i]

Sven7/Tyler, that sure is an interesting concept. I agree about venting the front wheel farings too.

This sort of gets into the whole argument about exposed wheels and fairings, don't it?

I would suggest covering up those rear wheels and smoothing it out back there.

There was a recent concept remotely similar to this less than a year ago. It looked like it would catch more air than it would deflect. I liked it just a little, because it dared to be different but that was about it.

I don't think this study is an improvement over my stuff, but it does squeeze the brain when attempting to explain why.

I did draw something like this a few years ago, I hinged the suspension arm/faring at the body which would cause it to act like a large fork (similar to a motorcycle, but with a pivot). When I thought about the moment arm action I was creating I quickly abandoned it.

[aerohead]

Originally Posted by kach22i

Using the reasoning above, one could then argue that Zone-1 and Zone-2 pressure zones illustrated below, destroy any chance of Zone-3 working at all, even though it conforms to the template.

Automobile 2 - Odds and Ends pictures by kach22i - Photobucket


Also using this reasoning, there is not a car or truck out there which can benefit even a little bit by attempting to make one part or another (typically the aft section) template friendly.

I cannot accept this as an all or nothing, black or white proposition. What has everyone in the forum been doing with all of their efforts then? And what of all the results and success stories?

And what of Zone-4?
Automobile 2 - Odds and Ends pictures by kach22i - Photobucket


I did a little more work on the "1.5 body" last night, scanned and did the overlays this morning. I do want to bring it "all together" in the end.
Industrial Design - Transportation pictures by kach22i - Photobucket

*It is the pressure gradient from the max camber point aft which is critical to the streamlining.
Automobile streamlining is about minimizing or eliminating separation at the rear of the car.The 'Template' cannot produce separation.
*The Insight has more 'nose' than it needs for low drag.If it had the Schor car front end it wouldn't suffer a drag increase at all.
*Like all cars,the Insight has an incomplete tail and there's still a 50% drag reduction possible for the car by extending it.
*If you're going to stitch components together to create a car that's fine,but you'll need to follow the hard and fast rules established long ago to maximize your performance.This is why I recommended Hoerner for one.He is an aerodynamacist and he's done complete body-discard and alternate-body install wind tunnel testing for real cars.He was also involved with the design and testing of Messerschmitt's fighter aircraft.You can see two examples of his work in the recent movie 'Red Tails.'

[NeilBlanchard]

George,

Have you seen the Illuminati Motor Works 'Seven'? It is an elongated variation on your latest sketch:



Their packaging compromise is to have the two rear seats face backwards. It is probably a little longer than it needs to be, but not by a whole lot.