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Measuring Fin CG

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mccordmw

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Starting my fin flutter analysis. When measuring the fin CG, should I balance the fin with the through-the-wall tabs or with them cut off (on a sample, of course). I would thing the CG is for the fin up to the point where it meets the airframe, right? So balancing should be with a fin where I've sawed off the TTW tabs.
 

Aksrockets

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If you're assuming your root chord is rigid, flutter analysis doesn't care about fin tabs because those will not contribute to flutter in any way. Measure from your root chord.

What flutter model are you using?

Alex
 

Nytrunner

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I vote without the tab.

If your fin design can be broken into primitive geometries (triangles/rectangles), its pretty quick to calculate the CG by hand.
 

mccordmw

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If you're assuming your root chord is rigid, flutter analysis doesn't care about fin tabs because those will not contribute to flutter in any way. Measure from your root chord.

What flutter model are you using?

Alex
Using Finsim. Just starting to learn it.
 

OverTheTop

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If you're assuming your root chord is rigid, flutter analysis doesn't care about fin tabs because those will not contribute to flutter in any way. Measure from your root chord.
Go without the fin tabs. They do not contribute to the aerodynamic forces on the fin. They do make for a much more solid root which will increase the resonant frequency of the fin (and attachment strength :))and improve the flutter outcome, but it is not what the program is asking about it for I believe.
 
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