How is CG determined on planes with swept back wings?

Thanks

You need to find the MAC for your wing.
Check out the following web site
http://www.airfieldmodels.com.

Thanks, that is a great site! I don't have any plans for the plane I am working on, so finding the CG has become a challenge.

Thanks again!

You are welcome, Paul has a really great site, what a builder he is did you see his latest scale build?
Glad that helped you out. His site is really good one for anybody who wants to build.

Hey winger1955,
The measurements to figure CG are real easy to do with a tape or yardstick even. They don't have to be any more accurate than you would get with a wooden yardstick and eyeball. Then plug them into the CG estimation application at that website, and you're good to go.

Only tricky measurement on a swept wing would be the LE sweep. And with a model, just lay out the wing by itself (if it's one piece) on the floor to have room and a flat reference area. If it's two piece lay the model upside down in the yard.

I hope this helps

Thanks Uby, it does help!

This is perfect.
I presented this in another forum because i wanted to to find the CG for my wing using this theory/diagram. Best answer i got was the typical 1/4 - 1/3 back from LE.

So i will let you gents work out the numbers and see if you came up with what i did. :P

Desired 25% chord CG.


one wing half:
Root Chord: 9.0 inches
Tip Chord: 5.5 Inches
Wing Half Span: 16.25

Winger1955,

take Uby's sketch, go to LE at the MAC shown, and go back towards TE around 30%, following the MAC rearward. Then project that point to the root chord. That's a good place to start for a cg estimate. Adjust from there to your taste for response on the model

MattK

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You need the leading edge sweep dimension also.