CG and swept back wings?
 

How is CG determined on planes with swept back wings?

Thanks

RE: CG and swept back wings?
 

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

RE: CG and swept back wings?
 

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!

RE: CG and swept back wings?
 

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.

RE: CG and swept back wings?
 

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.

RE: CG and swept back wings?
 

I hope this helps

RE: CG and swept back wings?
 

Thanks Uby, it does help!

RE: CG and swept back wings?
 

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

RE: CG and swept back wings?
 

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

RE: CG and swept back wings?
 

.
You need the leading edge sweep dimension also.