Heel the Turn-Leaner

The leaning has a name — bank — and the little flaps that do it, out near the wingtips, are the ailerons. "One aileron goes up, the other goes down, so one wing rises and the other drops. Now the whole plane is tilted — banked — and here is the part that took me the longest to see." She held a model wing flat. "Lift always points straight out of the top of the wings. When the wings are level, the lift points straight up, holding the plane against gravity. But when you bank the wings—" she tilted it "—the lift tilts with them. Now it points partly up and partly sideways. And that sideways part is a force pulling the plane into a curve. The plane turns because its own lift is now aimed into the turn."

The Advanced idea, she stressed, is that you did not add a sideways force. "You already had all that lift, pointing up. Banking does not make new force — it re-aims the force you already had. Tilt the wings, and some of your up-force becomes turn-force. Which is also why a hard bank makes you sink a little: you borrowed some of the up-force to make the turn, so there's less holding you against gravity. That is why, in a real turn—" she nodded toward where two other flyers worked "—you also lift the nose a touch to make up the borrowed lift. But the turning itself is pure lean."

A flyer objected that surely you steer with the tail, like a rudder on a boat. "The rudder helps — it keeps the nose pointed neatly along the curve, no skidding," Heel said. "But the rudder alone just skids you sideways, flat and ugly. The turn — the clean carving curve — comes from the bank. Lean first. The tail only tidies it."

A careful young flyer named Fen kept trying to turn her plane by bending the tail-rudder and got only a flat, skidding wobble. Heel bent the wingtips instead — one up, one down. "Stop pushing the nose around," she said. "Tilt the wings and let the lift do the pulling." Fen threw it, and the plane leaned into a long, smooth arc and came home.