Induced drag and influences

[Sean van Hees]

I've got a question regarding the induced drag determined by VSPAERO.

How is the induced drag determined and does the mesh build-up influence this. In my model, it yields some negative induced drag coefficients at a number of angles and I cannot seem to figure out how to resolve this matter. I suspect it is caused by the way this model is meshed, but I am just unsure.

Could you please help shed some light onto this matter?

Regards,

Sean

[Brandon Litherland]

I changed the surface resolution in places to better set up for VSPAERO.  I then ran in Hybrid mode with your Thick and Thin sets.  I think most of the problem is the IVT angle to the body.  You can see in the first image that there are nearly overlapping panels which will cause lots of problems for any solver.  Rather than place the tail along the surface of the body, fully embed the tail to provide a good intersection.  You'll get a good polar after that.

[Sean van Hees]

Thank you Brandon for the suggestion. I have given it a go, also improving the tessellation and clustering settings and the results remain consistent currently.

I put the IVT on the body as this resembles the system I am reproducing. With that, I did not consider the effect of overlapping panels.

Op dinsdag 11 augustus 2026 om 13:44:13 UTC+2 schreef Brandon Litherland: