Here’s the key to tuning: Tiny, almost imperceptible changes have a dramatic impact on the boomerang’s behavior. Tune the wings one at a time, making a single change (e.g., adding a little dihedral or positive attack), give it a test toss, then tune some more.
There are three aspects to tuning: dihedral, positive attack, and weight:
Dihedral is a curving of the wing so that it doesn’t all lie along a single plane. Increasing dihedral makes the boomerang climb higher, follow a more circular path, and lay over sooner to finish with a long hover (which makes it easier to catch). Adding lots of dihedral makes these light Cardboard Boomerangs travel fast and tight. To add dihedral to a boomerang’s wings, hold the boomerang by the hub with its face toward you, and pull the wing toward yourself (Figure 18-17).
Positive attack is a twist along the length of the boomerang’s wing, which slows the boomerang down, resulting in a flatter, rounder, lower flight path. To add positive attack, hold the boomerang by its hub with the boomerang’s face up. Looking at the edge of the wing, twist it counterclockwise (for right-handed throwers) or clockwise (for left-handed throwers), lifting the leading edge of the blade (Figure 18-18).
Adding weight increases momentum, resulting in a longer, more elliptical flight. The easiest way to add weight to a boomerang is by taping pennies to one or more wings. The effect will be more pronounced as you put the weight further toward the tip. Add weight to one wing at a time. It’s easiest to throw a weighted Cardboard Boomerang if the heaviest arm is directly opposite the one you are holding when you throw.
And, of course, if any of these behaviors are too pronounced, you can always decrease dihedral and attack. You can even try a negative dihedral or attack, which rarely work with these multi-bladers but can be useful with some more exotic store-bought boomerangs.