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Old 06-04-2012, 07:05 PM   #10 (permalink)
aerohead
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think

Quote:
Originally Posted by kach22i View Post
No, as far as I understand it (but I'm not Aerohead).

I think thats the point of the 5:1 comment in close proximity to the ground, verses the 3:1 of "free air".
Yes,if the 'Template' is placed over a mirror,and you look at it and its reflection,you see that its L/H=5,and L/D=2.5.
Without wheels,in ground effect it is Cd 0.08.
Without wheels,in free flight,it is Cd 0.04.
With wheels,and in ground effect,it would be on the order of Cd 0.12+,depending on the wheels/tires.
With comprehensive wheel fairings,as seen in record cars and solar racers,the Cd would go below 0.12.
The 2.5:1 L/D is about the shortest ratio which still respects Mair's 22-degree back-slope limit for attached boundary layer flow.
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