AVL Tutorial (2) - Model your Airplane
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- Опубліковано 9 лип 2024
- This AVL Tutorial - Part 2 - will teach you how to model your own airplane geometry in a simple text editor for calculation in the Athena Vortex Lattice Code, which is very useful for quick and reliable Aerodynamic Analysis, Trim Calculation, Dynamic Stability Calculation.
I used it extensively in my Bachelor Thesis and further works on the battery-electric touring motorglider FVA 30 (www.fva.rwth-aachen.de/), as a research assistant at the Flight Systems Dynamics Institute of RWTH university (www.fsd.rwth-aachen.de/) and for personal UAV and model aircraft design.
AVL was written by Mark Drela and Harold Youngren (Massachusetts Institute of Technology).
"AVL is a program for the aerodynamic and flight-dynamic analysis of rigid aircraft
of arbitrary configuration. It employs an extended vortex lattice model for
the lifting surfaces, together with a slender-body model for fuselages and nacelles.
General nonlinear flight states can be specified. The flight dynamic analysis
combines a full linearization of the aerodynamic model about any flight state,
together with specified mass properties."
More information on web.mit.edu/drela/Public/web/avl/
Great video! Very useful!
Very useful, thanks!
Much appreciated!
Great Video series @Benjamin Kelp
Useful video, thank you, could you upload part 3? I'm having trouble when running. Regaardsss!!!
Hey Mauro, thanks for the feedback. Part 3 is upcoming.
Hello , how can i make my control surface to be replaced by angle.
Hi, i was wondering if AVL can take as an import an .stl or some form of CAD file generated in a CAD software (i.e. Rhinoceros) or if the only way to import a geometry is through the avl geometry file.
Hello, may I know if it is possible to model a V-tail in AVL? and if so how would you go about doing it? Thank you
Hi, these were great videos. I have a problem - when I open the geometry window, keystroke mode does not work even though I have the cursor in the window when I hit LRUD. The picture does not rotate at all. I don't know what to do; it seems to work perfectly fine for those doing the tutorials on UA-cam. Do you have any idea what might be causing this issue?
Sorry, no idea. Have you "clicked" and activated that geometry window?
Hello! Thanks for the video. In the Control declaration, pls explain usage of XYZhvec.
It gives you the hinge vector. However, in my experience it doesn’t really matter - seems AVL hasn’t implemented this for the standard use case.
@@BenjaminKelm Thanks for your answer. However, it does matter as a declaration. If you put another declaration instead of 0.0.0., you obtain different stability derivatives. I have checked it. I don' t know what the usage in declaring a hinge vector different than that of the real hinge line would be, however. That's why and as per common practice, I always declare the vector along the hinge line (0.0.0.) and thus obtain the stab. Derivatives as they should be.
Can you please explain what non unity Gain values physically represent for control surfaces like elevons? And how do you find these values for a model?
Gains are just simple multipliers to the control surface input. Mainly interesting for mixing different control surfaces. Hope that helps
hello sir, have a question regarding the drooped wing. if the wing is divided into n sections for instance n=10, from n=8, have to droop the wing. so how to do that in AVL, sir?
Consult the manual - it's possible to set an incidence angle for each section.
When changing the values in the Supergee.avl file, can we work in any unit system of our choosing?
Yes, the units are typically defined in the .mass file
How can I calculate incidence angle from the sketch of wing?
Just see what angle the skeleton line of the profile has compared to the x-axis of your plane. That might not be well defined - that's why we talk often about "incidence angle difference" between wing and tail surfaces.
I am having a weird problem that I cant really fix. whenever i tried to load the file that i created for my designed plane, AVL just shuts down. if anybody knows what exactly is the problem please answer this comment
Hello, I've just started to use AVL but it seems to me that you are running AVL directly and not from CMD. Try to run it from CMD. AVL might still crash but CMD will stay open and will show you the errors. The same thing as you describe was happening to me. I've changed the values of Nchord, Cspace Nspan Sspace (distribution of vortices) through trial and error.
values which worked for me 7 1.0 30 0.0 ! Nchord Cspace Nspan Sspace
Sometimes this can happen (under windows) if the file was not set up properly (like having TABS in there).
Also these top declaration might cause problems (Under Windows) if they are not defined as floats (0.0 not 0)
Example .avl file:
Bubble Dancer RES
0.0 Mach
0 0 0.0 iYsym iZsym Zsym # 0 instead of 0.0 might cause an issue in Windows.
1000.0 10.0 116.6 Sref Cref Bref
Just try to keep an eye out for that.
How to make cp 30 degrees from 25% of the root chord???
What do you mean by cp 30 deg?