For all practical purposes my Four Star 40 is done. Just have to replace some engine parts and tune it up. Now it will sit for 2 months until flying season. (It's only about 10 - 15 degrees here today.) [>:]
It balances about 1 inch ahead of the center of the main spar. If I put 4 ounces of weight way back against my Sullivan tailwheel bracket it balances out fine. A guy at my LHS said he likes them to be a little nose heavy. I wonder if this is too much or should I see how it flies and adjust as necessary?
By the way, I am balancing it upside down. I assume that is the correct way for a low-wing airplane.

DaveCFI

Yep.

It will fly nose heavy. But it will fly nose heavy. Most often it's preferable to fly them as the designer intended.

Dave,

You are right to balance a low wing upside down. This puts the mass of the plane below the point of suspension for better stabilization.
I would balance the plane per the manufactors instructions. Then adjust as needed.

Ditto, an inch forward of the CG is VERY nose heavy. Get it closer to what the manual suggests regardless of how much weight is needed

Hi Dave,

What are you using to balance and find your CG?

Try the Vanessa CG Machine. Cheap, Easy and accurate.

You might find out that your not that far off [8D] or you might find out you're further off than you thought too [:@]. either way this method is very accurate.

Here's the link.

http://www.rcuniverse.com/forum/m_70.../tm.htm#708060

By the way...

With the Vanessa method... your plane can be right side up or upside down. It'll work on mono planes and biplanes.

Very cool! I think I'll give the Vanessa method a try. Looks easy and inexpensive!

Thanks for the suggestion.
DaveCFI

For the Four Star two index (or middle) fingers are as good and accurate as is needed for balancing.

It is exactly that... easy and inexpensive. IMO even easier that "two indexfingers" because you don't have the finger roll factor and you can do it easily by yourself on any size of plane. Let us know how it comes out for you.

This is how I do it on small birds.....

Exactly.

I found the 'Vanessa' rig on here a while ago (different thread though, didn't have the 'Vanessa' name).

And despite having the GP jig, I much prefer the Vanessa method. Less chance of the plane crashing down due to massive off-balance, or an ill placed jig. No worries if you're called away for the phone, or for dinner..

Also, the cat won't knock it over when she's jumps up & gives it the typical 'cat affection rub' !!

It'll take a bit of practice, but is well worth it.

I had one of the GP jigs too... until last year. I had a TF Contender that I just finished building balancing on it nice and pretty. Until... something decided to slip and down came the Contender. [:@]

I think the guy that did the Venessa thread comments about similar problems with the GP Jig. or doing the ol' two pencils (eraser side up) having the same problem.

I have had a 4*60 in the past and was very happy with it... and quite honestly that design will tolerate a fairly wide range in CG. Nose heavy will just make the thing sluggish on the elevator for the most part. And... better to be nose heavy than tail heavy. [&:] But with a good cg machine atleast you'll know exactly where you're at and adjust from there. (Good practice for future or more picky models [8D] )

Dave, send me your e-mail and I can provide a spread sheet all set up for balancing any size plane from very small to full scale. All you have to do is change the values in the correct cells to fit your plane. It is very easy to use and all you need is a small scale to weigh your plane at a couple of places. This system is spot on perfect in finding the C.G. point . Then after that you can move weight around to fine tune the plane to fly like you want. I tried sending you a e-mail via this site but it got kicked back as undeliverable.

Steve