Balancing a biplane
 

I am trying to balance a Sig Smith Miniplane, (I know this isn't a 3D question but this is the only forum I bother to read), and I am struggling. The first time I tried, it flew tail heavy but it seemed to balance ok before takeoff. (Tank empty) So I thought I would try the Great Planes balancer. It seems impossible to actually make it balance. Should a biplane be balanced upside down or rightside up? The CG is shown about 1/4" from the leading edge of the bottom wing. It is very difficult to make the plane sit on the machine because it is so close to the leading edge. Do I balance by projecting the CG strait up to the top wing and balancing it there? Help as I would prefer to keep this plane in one piece. Thanks
Don

RE: Balancing a biplane
 

The best way I have found to balance bipes is start out with the cg at 25% mac chord the overall chord of both wings. you allready have the cg mark then projct it to the top wing as you said and have someone hold there finger under the top wing on one side while you hold yours under the other. lift the plane off the bench and see how you are, move or add weight as needed.
This will work fine and will only take a second to do
hope this helps
Derf

RE: Balancing a biplane
 

Last time I balanced a biplane, I attacked the problem a slightly different way. I marked the C of G range on the top wing, then decided where I wanted the C of G in that range. It was where the wing panels join so I drilled a 1/16 hole through the covering and glass join in the wing into the pair of ribs that formed the join and screwed in a cup hook. I then balanced the plane front to rear as well as laterally , el perfecto!
I then covered the hole with a sticker, you'd never know it was there, but its quite easy if you ever need to reckeck the balance.

RE: Balancing a biplane
 

I have always seen bi planes balanced at the top wing.
I have two where the person swore it was balance but we kept moving everything forward and we found that if he has used the top wing, everything would be fine.

Balance it useing the top wing and if it is TOO tail heavy, then you can ways move it back.