ORIGINAL: MinnFlyer

it had a fair amount of adverse yaw

[link=http://www.airspacemag.com/flight-today/Upside-Down.html]Original article[/link]
AILERON SPADES
These shovel-shaped surfaces, rigidly mounted on arms forward of the ailerons, provide “aerodynamic balance,” reducing the effort needed to roll the airplane. Aerobatic airplanes need aerodynamic balances because their control surfaces are large and their speeds are sometimes high. When the ailerons are neutral, the spades are aligned with the airstream and do nothing. But when an aileron is deflected upward, for example, its spade tips downward. Air presses against it, helping the aileron along, just as the weight of a small person on one end of a teeter-totter helps a larger person at the other end push off the ground. The farther the aileron is deflected, the larger the force supplied by the spade. Aerobatic pilots describe spades as akin to power steering.

“Spade design is a black art,” says airshow pilot Patty Wagstaff. “You see all kinds of shapes and all sizes, depending on the airplane. Akro pilots are always tweaking them to get the control feel just right—not too light and not too heavy. I’ve flown without spades, and it was like driving a Mack truck.”