How to estimate drag of a thick airfoil?
How to estimate drag of a thick airfoil?
(OP)
Hi guys,
How do I estimate the drag of a well designed deep camber airfoil with a height to length ratio of 1/4.5 with 20% accuracy?
Lift is not important, just need to minimize air resistance
The aspect ratio would be 1/3, not sure if that matters much though
I haven't been able to figure out how to work any of the software :/
Also how would the drag coefficient be affected at varying speeds from 40-200 mph?
In case we end up talking about different shapes, I mean the one labeled "deep camber" in the picture:
http://www.allstar.fiu.edu/aero/images/fig18.gif
How do I estimate the drag of a well designed deep camber airfoil with a height to length ratio of 1/4.5 with 20% accuracy?
Lift is not important, just need to minimize air resistance
The aspect ratio would be 1/3, not sure if that matters much though
I haven't been able to figure out how to work any of the software :/
Also how would the drag coefficient be affected at varying speeds from 40-200 mph?
In case we end up talking about different shapes, I mean the one labeled "deep camber" in the picture:
http://www.allstar.fiu.edu/aero/images/fig18.gif





RE: How to estimate drag of a thick airfoil?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: How to estimate drag of a thick airfoil?
yes Re is important.
Another way of looking at it is that at zero lift it is pretty much the same friction as an ellipse of the same depth/length ratio, so look up the answer for that.
Cheers
Greg Locock
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RE: How to estimate drag of a thick airfoil?
changing speed from 40mph to 200mph will also certainly affect the results (re Reynolds number).
how/why was the foil shape chosen (a narrow thickness with a pronounced camber, like an engine turbine blade) ?
what does your "length to height ratio" mean ? i mean aspect ratio is span/chord ?
any "good" CFD program should get you what you want, but i'm guessing you don't want to pay for it ?
another day in paradise, or is paradise one day closer ?
RE: How to estimate drag of a thick airfoil?
You could consult the book "Fluid Dynamic Drag" by S. Hoerner. It has a lot of drag info on objects with various shapes.
Andries