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CG and swept back wings?

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CG and swept back wings?

Old 12-03-2005, 07:37 PM
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winger1955
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Default CG and swept back wings?

How is CG determined on planes with swept back wings?

Thanks
Old 12-03-2005, 09:07 PM
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iron eagel
 
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Default 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.
Old 12-04-2005, 12:33 PM
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winger1955
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Default 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!
Old 12-04-2005, 12:38 PM
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iron eagel
 
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Default 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.
Old 12-04-2005, 05:40 PM
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da Rock
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Default 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.
Old 12-07-2005, 02:25 PM
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uby
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Default RE: CG and swept back wings?

I hope this helps
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Old 12-07-2005, 08:12 PM
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winger1955
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Default RE: CG and swept back wings?

Thanks Uby, it does help!
Old 12-08-2005, 02:13 AM
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radecatur
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Default 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
Old 12-13-2005, 10:41 PM
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Default 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
ORIGINAL: winger1955

Thanks Uby, it does help!
Old 12-13-2005, 11:17 PM
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Tall Paul
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Default RE: CG and swept back wings?

ORIGINAL: radecatur

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
.
You need the leading edge sweep dimension also.

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