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Old 01-13-2013, 09:33 PM   #71 (permalink)
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KamperBob: Thank you very much, I had some doubts about where to align the ground plane in a plan view, I had seen some done this way so that's what I followed. Thank you very much, I appreciate the input,

EDIT: Here is the updated overlay, with the ground plane aligned down the centre of the truck, and as KamperBob said, it provides more taper than the previous one. If there is still more tweaking required, let me know, I appreciate the input.


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Old 01-13-2013, 10:10 PM   #72 (permalink)
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Thanks Phil, lots in that post. Read the 29 pages (and followed some links) on the trailer boattail last night. More reading to do....

Your answer (and more reading) has made me realize I was really misunderstanding the optimum part of the boattail template. I was thinking it was the minimum to maintain attached flow, but it isn't. It truly is an optimum boattail. Shorter ones work, but not as good. Longer ones, well, longer just isn't required. There's probably a "minimum" boattail template that could be made, but it may not be as universal, and who would pick just what metric defines minimum?

Back to my case, my motorhome, the sides would really dominate the boattail. The height that makes the optimum tail so long, becomes half the width and the tail gets MUCH shorter. And using the shape that works for the sides on the top makes a pretty decent tail. At 4' long, it'd be just past 50% of an optimum tail, and be down to about 21.
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Old 01-14-2013, 10:42 AM   #73 (permalink)
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Quote:
Originally Posted by 2000neon View Post
KamperBob: Thank you very much, I had some doubts about where to align the ground plane in a plan view, I had seen some done this way so that's what I followed. Thank you very much, I appreciate the input,

EDIT: Here is the updated overlay, with the ground plane aligned down the centre of the truck, and as KamperBob said, it provides more taper than the previous one. If there is still more tweaking required, let me know, I appreciate the input.

Your plan overlay now reveals the classic pickup aerocap conundrum. Airflow around the cab could attach that soon behind if not for untapered bed width. Imagine a flat tonneau then template shaped cap on that. The resulting shoulder wouldn't support attached flow.

As an exercise use the overlay tool one more time. This time use width at the top of the cab. It's considerably narrower there so the minimum attached form could be even less that that higher elevation above the bed rails.



IMHO that low pressure zone would generate detachment and a vortex that would spoil intended gains of an ideal aerocap. So compromise.

You could design the top the hit that. Blend the rear sides to smoothly meet the bed.



Then make it practical.





It's too bad I lost my shop. That's what I wanted to build. Someday. Maybe.
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Old 01-15-2013, 02:47 PM   #74 (permalink)
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I think those aero caps would sell if you had decent production and marketing. Just my personal opinion, I think that first design with the flat shoulders would look incredible on a sport truck, lowered down and a few aero tricks, I think that would be cool! For aero and function, your other designs look awesome.

I see what you're saying about the width differences from the top of the bed compared to the sides of the truck. Here is what it looks like set at the width at the top


Compared to full width:


I'm shocked, I had no idea that the tapered in that much at the top of the cab. Now I'm wondering if that is just this generation of truck, or all of them. Now I want to see one on the road to take a closer look at one.

Of course this is all assuming that I've applied the template correctly, if I have not, I will gladly accept criticism and advise on how to do it better.
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Old 01-18-2013, 12:34 PM   #75 (permalink)
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Hello,
sorry to ask, but does this link work? i attempted to upload a pic of my 90 honda civic hatchback and i didn't see it like the posted pics.
Perhaps i do not have full access?
i wanted it to work like this link:
http://ecomodder.com/forum/showthrea...ect-19662.html
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Old 01-22-2013, 11:48 PM   #76 (permalink)
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When you upload the picture, you will have to drag the template to the picture, and adjust the size and position as necessary.

Here is a quick one that I did, the picture of the car isn't level, so the alignment along the roof is a bit off, but it gives you a good idea of where it will go.

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Old 01-23-2013, 02:16 AM   #77 (permalink)
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Hello,
Thanks 2000neon for your assistance to line up the template.
NOTE: I attempted to 'upload' from my computer but it didnt' work, perhaps i have to link a webpic?
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Old 01-23-2013, 06:21 AM   #78 (permalink)
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I have always upload a saved picture. After selecting the image and pressing upload, try scrolling down from the "menu" and look below it, first for me is the picture, with the template below that.
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Old 01-24-2013, 08:36 PM   #79 (permalink)
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I don't know where you read to put the template ground plane in the middle but I firmly believe it is incorrect and will result in a serious pressure differential where a low pressure area will be on the side. It will not be optimal.

This is the correct application.

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Old 01-27-2013, 12:02 PM   #80 (permalink)
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Correct?...

Quote:
Originally Posted by ChazInMT View Post
I don't know where you read to put the template ground plane in the middle but I firmly believe it is incorrect and will result in a serious pressure differential where a low pressure area will be on the side. It will not be optimal.

This is the correct application.

Can you please explain your reasoning?

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