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Old 01-23-2013, 11:02 PM   #402 (permalink)
Master EcoModder
Join Date: Feb 2012
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The Truck - '02 Nissan GU Patrol ST
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Originally Posted by aerohead View Post
It looks pretty good!
The faster initial may trigger separation,but the geometry is so good a little downstream that reattachment is a given.
In Hucho's book,he presents a drag table which contains the 2.5:1 L/D streamline body of revolution that was the inspiration for the 'Template.'
If you can gain access to his book,you might be able to cleanup this 'tiny' image and scale it up.
I did what I could with copy machine photo-enlargements,but it renders a fairly 'dirty ' image.
Thanks for all the gee-whiz image and math noodling.
I've been working on three other 'Templates,' to present which will give some options and different perspectives.No telling when I'll get those finished for posting.
Thanks again for all the work! I think she'd look pretty good in a tunnel!
I thought about that initial slope being steeper, but there are a number of reasons I don't think it will be too much of an issue.

1 / As per your comment above, the overall picture in this field seems to be much more important than the sum of it's parts.

2 / No disrespect here, I think nearly everyone here would still be floundering without your imense input, but I still have a bit of a question about the angles attached to the template, they do not seem to conform to a continuous curve, this suggests to me that some errors have been introduced in the process of transcription. So we know the template numbers quoted do get a positive result, but as there is discrepancy sugests that there is some room to play around these numbers, how much?, who knows?

3 / Many so called "streamlined", & proven vehicles seem to fall below the template curve enough to suggest they shouldn't be as good as they are.

I haven't got access to Hucho's book, but if I continue this hobby it may well get on the Buy list.

Copiers are great for a single copy without magnification, once you start magnification & copy of copies, the errors start to multiply out, fine for a visual representation, but not for a scale model, but as you said, if that's all you have to work with then you do what you can.

The whole math noodling thing, thanks, but I do it all through excel, PITA working out all the formula's and error checking, but once it's done, all you need to do is adjust paramaters and dimensions and it does all the calculations. Be great if I had some of those flow programs, but this takes too much of my time anyway, so probably better of without them.

If you wouldn't mind, can you elaborate on how the template angles were derived
Your opinion on how to apply template to sides of vehicle, as I have found it produces a very aggressive vertical profile which would suggest seperation.
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