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Old 08-06-2012, 03:02 PM   #11 (permalink)
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Old 08-06-2012, 05:35 PM   #12 (permalink)
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Originally Posted by Big time View Post
Which one offers the lowest overall drag:

A. A standard shaped roof where the roof is mostly parallel to the ground

Or B. a Kamm placed over a standard roof?
The roof continues upward inclination beyond the standard shape roof height to slowly taper down.

Roof camber data seems to show that while Cd decreases with higher roof camber, overall CdA goes up as the increase in frontal area won't compensate for the lower Cd.
In This Chapter the Modifications That Were Carried Out To

But there's a catch as this data is for a symmetric shaped roof camber where both upward and downward slopes are equal.
What happens when the upward slope (front) is steeper than the downward slope (rear)? Of course the max roof camber point goes forward.
here's the deal.Your talking about an 800-man-hour project just to find out.Around here,your talking about 55$/hour for a fabricator to do one turn key.That's a $44,000 experiment!
You could do scale model studies in scale wind tunnels and a final full-scale mockup in a full-scale tunnel.That would be $2,000/hour say at Lockheed Marrieta,GA.The A2 tunnel in NC might cut you some slack.
For my money,I'd be spending it elsewhere.
Sure,you can do it,but can you afford it for the good it will do you? Just playin' Devil's advocate.

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