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Feb 09, 2020, 07:16 PM
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vanessa cg balancer


I need someone's expertise in helping me understand the vanessa cg balancer I use. I have been in the hobby a long time but ran across a airplane with a high wing and open cockpit. the wing chord is 13 3/4 inches long and the vanessa balancer showed me the cg point was 6 1/4 inches back. Is this possible? If I use the 25% to 33 and 1/3 % method they do not even come close. I do not know where the cg point on this airplane is. Any help would be appreciated.
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Feb 09, 2020, 10:50 PM
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ChillPhatCat's Avatar
Just trying to understand the issue so please confirm... So you’ve got a used plane that supposedly flies with a CG of ~50% of the cord... assuming it’s correct?

It is entirely possible that a plane with a forward wing and aft tail group could balance there and be stable. There are a couple of ways... a very large horizontal tail or a very very long tail are one way... another thing that can move back your stable CG is if it has a lifting stabilizer... added lift on the horizontal stab creates a forward pitching moment on the plane and helps to serve as as substitute for a more forward CG position.

He best thing to do is post details, model name, dimensions... so experienced members can check out the specs or to take your measurements and plug them into one of several “CG Calculators” that you can find on Google... they can compute a stable range for you to start with.
Feb 11, 2020, 12:36 AM
AMA 46133
SeismicCWave's Avatar
Quote:
Originally Posted by rib man
I need someone's expertise in helping me understand the vanessa cg balancer I use. I have been in the hobby a long time but ran across a airplane with a high wing and open cockpit. the wing chord is 13 3/4 inches long and the vanessa balancer showed me the cg point was 6 1/4 inches back. Is this possible? If I use the 25% to 33 and 1/3 % method they do not even come close. I do not know where the cg point on this airplane is. Any help would be appreciated.
My question is that did the plane ever flew with CG at 6 1/4"?

If you don't know where the CG should be and don't know if anyone flew the plane with the CG that far back I would consider moving the CG forward a bit before doing any test flight on it.

Nose heavy plane flies like crap but tail heavy plane will only fly once. So I personally would put some weight in the nose and get the CG to at least 30 percent before flying it. You can always take the weight off afterwards.

If you don't think the Vanessa CG balancer is giving you the proper CG location, try using your fingers under the wing. I know high wing is a bit hard to check with your fingers because of the pendulum effect of a high wing plane.
Feb 13, 2020, 08:50 PM
Registered User
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I want to thank all of you for your suggestions. I found I was using the balancer all wrong. Thank You again.


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