Keel the Balance-Finder

The balance point has a name: the center of gravity. "It is the single spot where all the plane's weight seems to act — the point you could balance the whole thing on, like my plane on my feather. Gravity pulls straight down through that point, always. And the plane flies well only when that point sits in the right place relative to the wing — where the lift pushes up."

Then the Advanced part. "Think of the wing's lift as pushing up at one spot, and gravity pulling down at the center of gravity. For the plane to fly steady, those two have to be arranged just so. If the center of gravity is a little ahead of the lift, the nose wants to gently drop — and the tail, set at its angle, gently holds it up. That gentle tug-of-war is what makes a plane stable: nudge it, and it settles back to level on its own."

But the safe range, she warned, is narrow. "Slide the weight too far forward, and the nose is so heavy the tail can't hold it — it dives, like my first throw. Slide it too far back, behind the lift, and now there is nothing steadying the nose at all — the plane rears, wobbles, and tumbles. Between those two disasters is a small, safe window where the center of gravity belongs. Real aircraft builders mark that window exactly and never load a plane outside it, because a plane balanced wrong will not fly no matter how strong its engine or how smooth its wings."

A flyer asked how you find the window. "You test, like I did — balance it, launch it, watch. Nose-dives? Move weight back. Wobbles and rears? Move weight forward. Creep toward the spot where a gentle launch gives a straight, calm glide. That spot is the center of gravity sitting right where it belongs."

A determined young flyer named Bram kept adding weight to the nose to 'make it fly straighter,' and kept making it dive harder. Keel took the plane and slid the clip backward instead. "You don't need more weight," she said. "You need it in the right place. You pushed the center of gravity too far forward — now the nose is winning the tug-of-war." She balanced it on her feather, level, and launched a calm straight glide.