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Old Oct 06, 2001, 08:31 AM
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Joined Jan 2001
61 Posts
How to estimate CG on a Delta wing

Can anyone give me a ballpark for determining the CG on a triangular delta?

I have a model balanced at about 43.75% of the root chord and it seems unstable but does fly. I'm thinking that it may need to be about 50-55%. Any ideas?

Thanks

Lefty
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Old Oct 06, 2001, 10:46 AM
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Schaumburg,Il,USA
Joined Apr 2001
256 Posts
Lefty,

I think it's more like 27%. For the Mugi and the Pibros, which both are 800mm span, 400 mm length plain deltas with 0 tip chord, the reccomended C.G.s are at 205 & 210 mm from the nose.

There's a good C.G. Calculator at:

http://ourworld.compuserve.com/homep...le/page17.html


I've verified this with both models and it works out fine as a starting point.

Tell us more about your Delta!
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Old Oct 06, 2001, 12:46 PM
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Thanks,

I'll check out the calculator. Here's a picture of the delta. I got bored with my Lite Stik and built this delta last night.

Hey, you're not too far from me in Schaumberg. Where do you fly. I'm in Northbrook but don't fly at a club just in the park next to me and at the nature preserve in Buffalo Grove.

Cheers,

Lefty
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Old Oct 06, 2001, 05:14 PM
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United Kingdom, Bracknell
Joined Nov 2000
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For anything unusual I normally make up a cartoon version using thin sheet foam (ceiling tiles) for the wing. Either to scale, or for very small models full-size. Bend a tiny bit of reflex into the CG then add weight to the front till it glides nicely. Takes no time at all and gives me a nice warm feeling when it comes to test-flying the 'proper' model! Here's one I used this technique to get the CG for (wingspan 7", Cox TD020, glide like a brick ):
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Old Oct 07, 2001, 08:10 AM
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Thanks Bill,

I did the same with a paper aircraft and that's how I came up with the first estimate.

Tristan
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