Balancing a large model airplane
 

I had trouble trying to balance a large model, Sbach342 190cm wingspan by myself.
I cut 2 pieces of 3 mm ply from some scrap, cut 2 pieces of tubing, 5mm od and glued them to the ply pieces .
Taped these new "balancers to the wing, underneath, with masking tape with the tubing at the indicated cg.
Placed the model on two chairs so that the tubing could "roll" freely and voilÃ*...done.
See attached pics.
Dino

RE: Balancing a large model airplane
 

You do Know you should be balancing that plane upside down...

RE: Balancing a large model airplane
 

Check out a thing called "Vanessa". Should solve all of your problems.

Les

RE: Balancing a large model airplane
 

Hi!
I just use my finger tips to balance my 50cc Yak (218cm span)!

RE: Balancing a large model airplane
 

Not really. Have never had a ny problem doing this way.. Major CG location is determined by flying.

RE: Balancing a large model airplane
 

Very ingenious solution! Though low winged aircraft are typically balanced while inverted, I can't see where the CG would be any different.

RE: Balancing a large model airplane
 

When I build a plane I put in a hardwood block where the CG should be located. THen I hang the plane upside down from the ceiling of my shop. This will allow you to balance the plane forward to aft and wing tip to wing tip

RE: Balancing a large model airplane
 

Nice idea! I use two scrapes of thin ply one of which I partially drill an indent, glue the two together and tape centered on CG on both wings. Then use two phillips screwdrivers to balance. This way you can use short screwdrivers for biplanes. I bought one of those Sig balancers and thought I was building a plane, then it didnt work with any of my larger planes.

Harry

RE: Balancing a large model airplane
 

I have a Great Planes CG Machine and I love it, other than it needs a big boost to handle larger planes. I've put it on top of a stack of books to reach the wings on some larger planes.

RE: Balancing a large model airplane
 

Right, low wing models should be balanced upside down...mid wing does not make much of a difference depending on position and weight of all accessories.javascript:void(AddText(';)','_image/s4.gif'))

RE: Balancing a large model airplane
 

These slings will work on any and every plane. Just don't drop the plumb bob on the fuse. :-)

david

RE: Balancing a large model airplane
 

An oldtimer taught me this method several years ago. He called it "The Center of Neutral" method. It is a very accurate method of CG placement and it becomes more accurate if you attach the sling directly at the tail and nose of the plane. It has several drawbacks, though. First, you need to make sure that the thrust line is perfectly level. If it isn't, the CG will be way off from where you measure it to be. Of course, you need to use a level with almost any method to be the most accurate. Secondly, you need a lot of patience waiting for everything to stop swinging. Third, though it might be considered an advantage, you must balance the model laterally first to get it to sit in the sling. I've set my CG using this method and then put the model directly on the CG Machine for comparison and frankly, the only difference was that this method was more accurate as the point on the plumbob was easier to finely mark than the "pads" on the CG Machine. The two results were otherwise virtually identical. The CG Machine had the advantage of being much quicker and easier.

RE: Balancing a large model airplane
 

I screw in an eyebolt at the CG point. I then lift the plane with a hook to check th ebalance and adjust as necessary. The nice thing about this, is it tests both transverse and lateral balance. I can even usa a fishcscale to check the flying weight.

RE: Balancing a large model airplane
 

daveopam

If you turn your hook into a wooden dowel, that you can turn by hand, you can turn the dowel to adjust the attitude of the aircraft, and you have a Vanessa.

Les

RE: Balancing a large model airplane
 

Thanks Les. I had these pics on my computer from another post a year or so ago. So unfortunately the F-4U is not mine. :-( I just use a hook in the garage when I need a big model balanced.

Have a great day, david

RE: Balancing a large model airplane
 

":-( I just use a hook in the garage when I need a big model balanced. "

I hang mine on a piece of chain, that we installed in the cross beams, so we could hook the come-along on to it for pulling automobile engines.

Les

RE: Balancing a large model airplane
 

"I hang mine on a piece of chain, that we installed in the cross beams, so we could hook the come-along on to it for pulling automobile engines."

You might be a red neck if you have a hook in your garage to pull motors with. HAHAHA Are we related Les?


David

RE: Balancing a large model airplane
 

"HAHAHA Are we related Les? "

Don't know, but between raising three sons and a grandson, one needs to be adaptive.

Les