Aerodynamic Streamlining Template: Part-C

[jime57]

These threads have gotten so large that I have a lot of trouble finding stuff. Someone give me a pointer to the thread and hyperlink for the profile line drawing comparison between the old and new templates. I know I saw it, but can't find it

I'm building a favorites folder so I promise not to ask again.

[jime57]

Originally Posted by ChazInMT

First off, Thank You Phil for staying with us here in this Forum. Your insights are truly appreciated by me and everyone else I'm sure.

Here I made a "Digital Copy" of your AST-II and maintained the 1.7 aft portion per your guidance in the last post. It is within a pixel or 2 of what you have drawn, I did leave out some details and took the liberty of "Arching" the angle measurements.

I must say the degree of precision in your drawing becomes apparent as I was tracing it, it is difficult to explain why I say that, but it is very noticeable as I used my drawing tools as to how close you come to some very ideal curves. My hat is off to you once again.

Please tell me if this offends you somehow and I'll delete it from here immediately.

This is a small version.



Click HERE for a big (1600 x 800) full resolution detailed JPG version

Is there a spreadsheet which shows the percentage heights of the various sections so that one might construct a large template to lay over the top of a car? If so, I missed it.

[ChazInMT]

Post #553 in this thread has a bunch of measurements on it which would be a cinch to spreadsheet. Betasniper is better than me with his measurements. He's using real drafting software er something, I just mess with Mircosoft Draw in the Word program to make my stuff. I do a good job of copying, but I have no real technical information at my disposal to make precise angle or length measurements. The drawing tools in Microsoft do make it easy to render shapes once you get the hang of it with the "Edit Points" feature on "Freeform" shapes, you can easily make any shape of an arching line. I insert a picture, then insert a freeform shape over it and "Trace" it digitally.

But I digress, I hope the image that looks like this from Betasnipers post #553 helps.



Oh, and you may want to go to the UserCP and reset you options under "Settings & Options" > "Edit Options" >"Thread Display Options" > set Number of posts per page to 30, this will minimize the number of pages to sort through. You may want to reset "Images wider than this width..." to 1200 since it is going to cut them off at this point anyway, it'll make the pictures full size between the 590 setting now and 1200 anyway.

[kach22i]

Originally Posted by ChazInMT

the template..........

It never changes its proportions, only its size.

I agree!

Originally Posted by ChazInMT

My overlaying on the various foils above was meant to show you what you're talking about doing when you rescale the template.

No, rescaling means exactly that, and as you yourself stated "the proportions stay the same". What you did was just plain silly and an attempt to confuse the issue, another strawman argument of yours.

Originally Posted by ChazInMT

Where do you get the idea I altered the template.

Maybe it's because this thread is such a mess, but the only "line template" of the arc you are using is in your own photo account. The attempt to shorten the template is a response by the template worshipers to make it relevant when it hardly is.

Originally Posted by ChazInMT

FYI back at cha... Foils are wings, they're 3d, we're just looking at a cross section of it.

Bingo, half way there. Now if you can only see a wing as I do (see below) and acknowledge that arc is representative of a section cut, you might understand why the 3D shape and its side curves or terminations are so important. This is the drag you should be concerned with. Oh, and wings come in different sizes (LxWxH) yet may use the same NCAC profile (ratio), getting it yet?

Turbulence Modeling | CD-adapco


Maybe you should look at it in more than section, try plan view or perspective once in a while. Wings don't go on forever, they have edges - and messy ones too

Originally Posted by ChazInMT

Are you going to question the base line optimum shape too? Do you have a better shape that, "Looks good to you"?

I like the template arc for what it is, a starting point, and one I still use. It is however nothing more than a reference, it is not even a design.

Originally Posted by ChazInMT

And finally, the illustrations you put up are drawings of what people think the air is doing over the surface of the car. They're drawings.

By people you mean "me" when I draw things? Then yes, but everything I've drawn is also supported.

The CFD illustrations are a pretty good guide, I really don't think people are manipulating them by what they choose to think. They are only choosing which points to tag and follow.

Okay enough wasted time, took my lunch break, now back to work y'all.

[freebeard]

Either your a total fool, or you are now trying to misconstrue everything I write simply out of sport because this is fun for you. Quit trying to prove wrong all the points I'm making about this, have you noticed you're the only one to do so? If I were wrong, many people sitting on the sidelines would jump in and point out where I was off base.

Well, you are wrong; it's just that people can find threads that are more fun; Mr. It's-a-line-not-a-half-body-of-revolution.

jime57 Thanked you, maybe you have the beginnings of a cult.

[jime57]

Originally Posted by ChazInMT

Post #553 in this thread has a bunch of measurements on it which would be a cinch to spreadsheet. Betasniper is better than me with his measurements.

To be brief, thank you

#553 had exactly what I was looking for. A small spreadsheet is included which COMPLETELY answered my question.

[jime57]

Originally Posted by freebeard

Well, you are wrong; it's just that people can find threads that are more fun; Mr. It's-a-line-not-a-half-body-of-revolution.

jime57 Thanked you, maybe you have the beginnings of a cult.

Look, don't take my name as a recommendation for anything going on here. There are 3-4 guys who just won't let this thing die. Each is on the third or forth repeat of basically the same argument, so it is getting tiring, and the thread is getting corrupted.

1. I am an engineer myself, so I can understand the arguments, but they are getting highly repetitive.

2. I don't see anyone as particularly wrong, everyone is just talking past each other and not listening very well. There may also be some shouting just for the sake of hearing one's own voice - not sure of that.

3. I fully understand that the template is only a two dimensional tool and therefore has limited general usefulness. Phil never represented it otherwise, as it applies to existing automotive bodies. BUT, there are several examples of folks who have used the template to guide them in constructing boat tails which perform well on existing cars. Are the boat tails optimum? Not very likely, but it isn't within the capability of us amateurs to produce the optimum. Most have no access to CFD modeling and even if we did, that wouldn't suffice. We would also need multi-million dollar wind tunnels. Phil has written much about this limitation and I have respected him for admitting the limitations.

I have said what I think needed to be said. I have no intention of being drawn into an endless and useless shouting match, so please ignore me if I offend. I don't intend to do so

[ChazInMT]

I've gone back and deleted any unproductive "arguments" out of respect to the forum and this thread.

[Daox]

Closed this thread for a while. Cool off time fellas. Hopefully we can be more productive next time around.

[aerohead]

Originally Posted by Daox

Closed this thread for a while. Cool off time fellas. Hopefully we can be more productive next time around.

Doax,thanks for unlocking the thread!
I've got some more images to post which I think will benefit the members.