Quote:
Originally Posted by kach22i
Thank you Aerohead for putting this all in one spot.
I assume all of these radius's are modeled on a 90 degree return angle on a flat plane and not some complex curve tapered teardrop form with a NACA foil number.
Let's say one takes a symmetrical cord foil and cuts the fish head off at the thickest point, then puts a 2 inch radius at corners.
How much would that alter the drag coefficient?
See attached study.
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* In Walter Lay's 1933 research, he takes his Cd 0.12 long-tail and sticks a near-vertical windshielded forebody onto it. The drag degrades to Cd 0.35 ( his model #10 ).
* His model # 14, with more laid back windshield is Cd 0.30.
* Model # 18, with the most windshield rake is Cd 0.12, same as 'optimum' nose.
This is 3-D flow, and there is some 'forebody' leading up to the maximum cross-section, so it's conditional.