What Am I? Power steering
How aerobatic pilots get those crisp maneuvers
Gardeners know the difference between a spade and a shovel: A spade cuts cleanly through the dirt; a shovel rounds the hole. Aerobatic pilots call the flat plate installed on the aileron of aircraft such as an Extra or a Pitts a spade. When the aileron is deflected upward, the spade tips into the wind downward, creating a surface where the wind can help push the aileron up. That extra boost is why many pilots call spades “power steering.” The spade helps reduce the effort needed from the pilot on the stick to actuate the aileron. Spades reduce the force required to move the stick, thus reducing pilot workload, but they have no effect on how fast the airplane rolls. The need for spades is driven by the design of the ailerons, says aerobatic pilot Spencer Suderman. “The Pitts S-2C doesn’t have and doesn’t need spades because the ailerons are of a different design than on my S–2B. Typically planes with balanced ailerons, either mass or dynamically balanced, will not require spades.”
Superstars and spades
Michael Goulian
Extra 330SC “Spades act like power steering in a car. They lighten the aerodynamic aileron loads at high speed. That’s why you can see aerobatic planes rolling at very high roll rates at a very high speed.”
Spencer Suderman
Pitts S–2B. “I have flown the plane without spades to check the rigging, since they will mask rigging issues. After tuning the rigging then reinstalling the spades, it’s amazing how much lighter the stick feels!”
Patty Wagstaff
Extra 300 “Spade design is a black art. You see all kinds of shapes and all sizes depending on the airplane. Acro 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.”
