View Full Version : Visual Aircraft Center of Gravity Calculator (beta)

17-Feb-09, 13:30

Due my hobby flight sim project, I found a use for the tool with what I can measure, calculate and estimate the plane stability characteres from plane drawings.
I just like to get to same ballpark, not exact real life figures. Close enough is enough.

Screen shot (240k)

More about plane stability and two online calculators:

Sample .blend file with FW190A8 (366k)

#Visual Aircraft Center of Gravity Calculator (0.1b) by Xjazz
#This script calculate t the plane Neutral Point (NP) location from to the wing & stabilizator dimensions.
#This is tested with Aircraft_Center of Gravity Calculator by Dean A. Scott
#Adjust in EDIT MODE the wing & stabilizator size, aspect ratio and also distance to each another.
# Get back to the OBJECT MODE and run the script.
#Black cross - MAC position
#White square - AC position
#Blue Square - NP position
#The tail-arm, Vbar, and NP % MAC values can find from console.
#Things to do
#- On screen texts for the figures... somehow.
#- UI for few values

Sorry about double topic


19-Feb-09, 10:43

I made a simple menu to show up the calculation results to the user.


Sample .blend file

Is it possible to make a menu updating a real-time, when user adjusts the vertex or objects locations?


20-Feb-09, 16:04
I am tad confused...

I made a serious effort with a core problem and I just asked a help with a menu updating problem.

Did I provide to You a too lousy spelling/grammar/FX or what?

21-Feb-09, 14:56

Thanks to the Tuxer in www.opendimension.org (http://www.opendimension.org) (Finnish blender forum) for the good advice about script-link feature.

The menu problem is solved.

WIP screen shot

User can move and scale the menu in 3Dview.

To do
- Finish the CG pointer code with intent CG position or to actual CG position function.
- Check, check and check the output figures.

As you can see from picture, this is working only with rectangular shapes.

Are there available any similar applications for the flying model planes?

25-Feb-09, 02:55
First public beta

User can give in EDIT-mode a intent static marginal % to the green text field in calculator and see the result on plane.
User can move in OBJECT-mode the CG-marker on plane and read the actual position % from the calculator.
NOTE! This is still beta version.
The actual calculator .blend file:
http://www.mediafire.com/?sharekey=2585963c345f514f4012e8015643d9c835ffb551 9d3574eb

25-Feb-09, 08:05
Hi, I just wanted to say that it realy looks like a killer script... The reason nobody replied (I think) is that it's not a very general script, that means that there's not a lot of people who needs it. If you could post a video on youtube that show's the functionality of the script, that would be awesome too.

Keep it up!

25-Feb-09, 14:27
Hi Kothe,

I just had a problem with regular menu updating loop but the scriptlink fixed it.

Here is a fast&dirty silent short film. It wont tell too much to you, if you are not interest about plane physics.

This short video is meant for the people who already knows the traditional airplane design longitudinal stability concept, but don't know the Blender 3D and VACGC calculator.

The Blender heads can see the purpose of this script, if you take a look to the online calculators below.

The calculator script is doing the same thing but with self-explanatory visual presentation.

03-Mar-09, 13:38
Lets put here one more time :)

I added a function, which calculate the rounded wingtip area as a circle segment and take that to the total wing area calculation.

The horizontal line near wingtip is a reader-object, with what you can adjust the circle segment size. No better visual for that.

Anyhow the figures are pretty close even with given drawing :)