Kammback Angle Okay?

[blowncopcar]

Okay, Im going to raise it up first, before I extend it, just to see how much is gained right there, then extend it.... and i'll post the results for everyone.... I just cant go back to completely stock, it's pretty permanent

[kach22i]

Originally Posted by Sven7

-You're taking a lot of liberties with the NASA truck, suggesting in one image that it is simply 22 degrees and in another that it matches a scaled template.

I don't think you are that unobservant, so I have to assume you enjoy being a spit wad. In one image I show it does not exceed 22 degrees, in the other that it's a close match for an extremely scaled down version of the template.

Is this what you would rather see?
Automobile 2 - Odds And Ends Photos by kach22i | Photobucket


Kind of makes my point and not yours, don't it?

Originally Posted by Sven7

-The Volkswagen Golf was designed in the early 70's and was by no means an aerodynamic masterpiece. Picking apart the exact curvature from a non-orthographic image is pedantic.

Close enough to a true side view to make my point, I don't see you providing a better image.

Originally Posted by Sven7

-I've listened to reports from the aero lab at work and can tell you the car needs to be considered as a whole, not just some 30cm long segment on the back of the roof.

I would agree, but this is not an attempt to design a from scratch car body is it?

Here is a thread in which several early discoveries were made leading to my current perspective on things.

http://ecomodder.com/forum/showthrea...ign-18632.html

Originally Posted by kach22i

For reference
Automobile drag coefficient - Wikipedia, the free encyclopedia


For a template comparable, the new 991
Automobile pictures by kach22i - Photobucket

A response:

Originally Posted by winkosmosis

According to the almighty template, the 911 sucks. And yet it's one of the most aerodynamic sports cars at 0.28 Cd. You know why? Because the roof and rear window are sloped shallow enough that airflow remains attached and doesn't detach until the rear spoiler. Those angles are what matter here. If you made the 911 look like the template, there would be no advantage for flow attachment, and the cross section of the rear end would be much bigger.

This is a perfect example of the arbitrary and nonsensical nature of the template.

Forget templates and just make sure the curves of the body allow attached airflow all the way back at the desired speed! BTW, you notice there aren't different versions of the template for different speeds?

Mind you that I was not and am not in 100% agreement with winkosmosis, but taking what he had to say about the importance of attachment can certainly be applied to a scaled down version of the template. We are probably saying the same thing just going about it from a differing perspective or using a different choice of words.

The proof is in the numbers (Dryden Truck and Porsche Cd numbers).

EDIT-1:
http://s184.photobucket.com/user/kac...?sort=3&page=1

[MetroMPG]

OK, this has gone from debate/disagreement to personal insults.

And you're wrecking the O.P.'s thread.

Just drop it, please.

[aerohead]

I would comment that the NASA' Dryden Econoline has twice the drag of the 'Template.'
The Porsche would see a 57% drag reduction.
Neither vehicle could get there using what NASA or Porsche used.
If 0.238 and 0.28 were the ultimate goal,then NASA was able to squeak by Carl Breer's 1934-1/2 DeSoto Airflow,and Porsche was able to match Edmund Rumpler's 1928 Tropenwagen.
Both a great success!

[kach22i]

Originally Posted by aerohead

I would comment that the NASA' Dryden Econoline has twice the drag of the 'Template.'
The Porsche would see a 57% drag reduction.
Neither vehicle could get there using what NASA or Porsche used.
If 0.238 and 0.28 were the ultimate goal,then NASA was able to squeak by Carl Breer's 1934-1/2 DeSoto Airflow,and Porsche was able to match Edmund Rumpler's 1928 Tropenwagen.
Both a great success!

When you scale down the template, you scale down your success.

I have a new catch phrase.

Stock Porsche 911.......................................0.28 Cd
Porsche completely redesigns the 911 Carrera


http://ecomodder.com/forum/showthrea...1-a-13538.html
(1) Standard DeSoto Airflow sedan----------- Cd 0.546
(6)............................Full experimental aero: Cd 0.238


More than one way to get there?

http://encarsglobe.com/rumpler-tropfenwagen.html


http://ecomodder.com/forum/showthrea...-6-a-2670.html

Originally Posted by aerohead

NASA,at Dryden Research Center,Edward's Air Force Base,California ( I was there but didn't get to see any of it ) achieved a 15 % drag reduction on a Ford Econoline van,with a carefully executed and highly refined full bellypan.