Cannot got results from VSPAERO normally

[Eric Cheng]

Hi all,

My OpenVsp version is 3.24. 

When I use VSPAERO to calculate my model  "Lift body"(I posted it below), I found that the calculation result cannot be obtained .Without any results similar to the lift coefficient have been obtained. (as shown in the figure below). 

What I want to know is that VSPAERO does not work normally because of something  wrong settings?

 Hope to get your answer, thanks in advance!

Below is a screenshot of the settings and geometry model in VSPAERO.

(Calculation model-“Lift body”.PNG)

*.vsp3 file:

[Brandon Litherland]

This is a fuselage and as we've discussed before a body component (anything not a "wing" type) doesn't have attached wakes and will not contribute to lift and drag.  As there isn't a wing in this model, there isn't anything to attach a wake to and therefore it will not run.  Also, the fuselage resolution is much too high for VSP analyses.  Back off to something like 10 to 20 NumU between sections and about 41 NumW at the most.  You should also avoid setting very small skinning strength unless you have a really good reason to keep it that way.  If you want a linear transition between sections, uncheck the angle and strength boxes and it will uniformly snap a line of even curves between the XSec.  Never use 0.0 strength.  It causes the same issues that vertical sections lead to.  Collapsed points.  Please refer to the Skinning and Blending subject in the OpenVSP Ground School to learn more about these techniques.  If you fix these issues and then run the fuselage in Panel mode, you'll get something more appropriate.  Whether the results are accurate will be to be determined.

I just saw this.  You have your component rotated -90 about X (making Y 'up') and are running an alpha sweep.  This means that you are effectively running a beta sweep on the body.  In VSPAERO and VSP, X is aft, Y is right, and Z is up.  This is the convention for all aerodynamic directions (lift and drag) and the like.  Please keep this in mind in the future when you are trying to run models.

[Eric Cheng]

Brandon,

Thanks a lot,your suggestions are very helpful to me.

Eric