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Old 10-14-2015, 05:25 PM   #154 (permalink)
aerohead
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262 citation/ 181 edges

Quote:
Originally Posted by freebeard View Post
Citation needed. Is the CD for the fuselage or the entire airframe?

The MG EX-181 is like a widened belly tank. Would squaring off the lower edge help or hinder?
*The Cd for the Me-262 is from Hoerner's 1951 book.He worked for Messerschmitt.And the Cd is a frontal area Cd for the fuselage alone.
*The EX-181 is kinda like a flattened tank.Goro Tamai calls 'em 'flattened torpedos.' MacCready called 'pumpkin seeds'. It's similar to Jaray's half-airship body also.You can see Jaray's 1922 shape co-opted in this ALDER advertisment.

Aircraft picked up on it






Even the Skunk Works likes it

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*As to the lower edge,you'd want the edge at the bottom,not midway up.As shown at the top of Fachsenfeld's drag table

*A square edge would promote vorticity.(Funderburk & Carver)
*A 'sharp' edge has been found beneficial by the M.I.T. folks,but we're talking solar cars based upon laminar wing sections.(Goro Tamai)
*Until this has been specifically tested for in a more 'conventional' passenger car, my opinion is that we put about as much radius at the bottom edge as VW did with the front of the Gen-1 Golf.
If you look at the airdam flow of the T-100 at DARKO you'll see separation under it,kinda like this

In a crosswind gust,the little bit of radius might be beneficial.Just a tiny bit of curve.As GM has done at the back lower edge of their concept
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