Control surfaces : Make the whole stabilator move

[thomas...@gmail.com]

Hi Rob,

I am currently trying to make the whole horizontal tale plane (stabiltor) rotating using the ControlSurface option.

However, I am facing a problem because the stabilator a such a shape that I can not define the whole wing as a control surface. On the two pictures down below, I want to put the "Start length/C" to 0 and "End length/C" to 1 but I get a weird shape when increasing it.

I think about three solutions :

- Not using a control surface but just put a rotation under a certain rotation axis (but I will not have a proper ControlSurface)

- Maybe defining two control surface for the two components of the stabilator (due to its shape, cf images

- Understand how to make it work ! :)

Thanks a lot

Thomas C

[Rob McDonald]

The start length/C and end length/C are the chordwise measure of your surface (not spanwise).  So, it is hard for me to imagine why you would want to set them to 0,1.  Start with 0.2,0.2 (a typical control surface) and modify from there, watching what changes as you make changes.  For an all-moving surface, I would expect it to be represented by 1,1 for those settings.

However, as you say, that is non ideal.  Instead, I would not use the SubSurface capability and would instead just move the entire control surface.

As you point out, this means you can't use the easy control surface derivative code in VSPAERO, but all you have to do is run two cases -- one neutral, one deflected -- and subtract to estimate those derivatives.  That is exactly what VSPAERO does.

Rob

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[skyc...@gmail.com]

I don't know if this will work for you or not, but I have "cheated" this before by making a LE control surface and a TE control surface which both terminate at the same hinge line.  I then set both to the same value, and it sort of "hinges" the whole surface about the pivot.  I'm not sure of the validity of this system though.

[Mike Vivaldi]

The HSTAb on the aircraft im testing has a trimmable HSTAB, I attached the surface to a hinge to get the desired effect. Hope that is helpful