Everyone who asks where to locate their CG should learn to use http://www.geistware.com/rcmodeling/cg_super_calc.htm

Matter of fact, even people who don't ask should take the time to learn about Neutral Points and Margin of Stability. And an excellent place to learn that in one sitting is: http://www.geistware.com/rcmodeling/cg_super_calc.htm

There are probably other free online applications out there, and they'd also be worthwhile, but I happen to know about geistware.

Nowadays, the ARF mfg's have proven time and again that their understanding of their products is the understanding of a toy manufacturer who has simply expanded their product line. I've built well over 20 ARFs in the last year or so, and way more than half of them had mistakes. The mistakes ranged from silly ones to fatal flaws. To expect that industry to recommend correct CGs for every ARF is not a good bet. They've produced ARFs with wing attachment designs that would not have stood up to everyday flying (the Hobbico Sukhoi didn't stand up to 3 flights). One Decathlon fuselage had such weak fuselage stringers the top of the fuse aft of the wing was failing after the first outing, an outing that was only 3 trim flights long. Balsa where spruce should have been. I've seen two ARFs blow horizontal stabs that were made out of crap balsa when they should have had twice the balsa and it hard balsa, or spruce. A recent favorite ARF was sold with gear that placed the main wheels DIRECTLY under the CG. Needless to say, I bent new struts before the stupid ones were even installed. etc etc etc etc.........

So you're going to accept the ARF mfg's CG recommendation? Without at least checking it out yourself. It takes maybe 10 minutes to measure the airplane and enter the numbers into the geistware application.

A recent 60size ARF manual recommended a 1/4" (that is one quarter of an inch) CG range and was emphatic that you not to go outside that range. And their location was pretty much a joke. It's a joke to think a 60size would have such a critically small CG range in the first place. And the manual's text was obviously the compilation of previous, half-done descriptions from the mfg's earlier models of other models. It's great to keep the price down by using already done work, but not if the previous recommendations aren't correct, or sensible. And are probably the recommendation for an earlier model.

It takes 10 minutes to find out where the CG can be from an application that works very, very well and is absolutely trustworthy. CG is a function of the airplane's planform, nothing else. Measure that planform and do the math and the answer is GOOD no matter what the airplane is or who manufactured it. That's not worth doing?????

Back when all we had were either plans or kits, all of those came with information that you could count on. And some of us still found the formulas and did the measuring and math to see how far the CG could be moved. Today there is good reason NOT to trust the mfg's information, and doing the math is dead simple. You don't have to. It's done for you. All you need is a yardstick and pencil/paper. Back then, you had to learn lots of things to build models that lasted for you. Today is no different. Only difference is that most of the work is already done for you, good or bad. It's still up to you to look at the bits and pieces and parts and angles and decide if that landing gear is stupidly placed or not. Balancing the airplane is just one of the things that separate an experienced modeler from a beginner. So isn't it time to start working at becoming an experienced modeler.

jeez......... didn't mean to preach.............