Stability derivatives, flt vs stab files

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othmanaero

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Aug 25, 2021, 12:57:42 AM8/25/21
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I noticed that the flt file give a list of stability derivatives even when stability analysis is not selected.  What is the difference between these two files?

Also, I noticed that the flt file give the alpha_dot derivatives where the stab file does not.

Thank you,

Ashraf

othmanaero

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Aug 25, 2021, 12:59:36 AM8/25/21
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Correction... the flt file is not generated when stability analysis is not selected...

Question still remains, are these files intended to show the same data in different formats?

Ashraf

Rob McDonald

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Aug 25, 2021, 1:21:36 AM8/25/21
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To be honest, I hadn't even noticed the addition of the *.flt file.

I suspect it is the same information, just formatted differently to work with a set of tools used by some folks at NASA.

The alpha_dot derivative is only calculated when run in unsteady mode -- and there it is included as a part of a greater sum. 

There may be another explanation, but I don't want to speculate at this time.

Rob


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Rob McDonald

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Aug 25, 2021, 6:21:39 PM8/25/21
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I was pretty close.

I asked Dave -- it is just a new format for this data.  A file with this format was written out by a modified version of VORLAX.  People using tools derived from that wanted to be able to use VSPAERO without changing anything.  So, here ya go.

I would recommend you stick with the *.stab file and ignore the *.flt.

Rob

othmanaero

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Aug 31, 2021, 12:00:16 AM8/31/21
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Thank you, much appreciated.

Ashraf
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