Both surfboard and aircraft designers have to work with three forces of rotation: yaw, roll, and pitch. These three forces work together to either make you squirrely, smooth, or quick. Pilots control these forces with rudders, ailerons, and elevators. Surfers do it with arms, toes, and feet.
And Surfers Do, Too
To illustrate, let's compare a pilot's right turn and a surfer's (normal
foot) front side bottom turn.
AIRCRAFT
All pilots know what "step on the ball" means. Step on the right rudder pedal, the nose yaws right. Crank the stick to the right and the ailerons bank or roll the airplane to the right. Most of the time, pilots don't move one control surface without moving the other—otherwise, "the ball" swings wildly and we have to step on the ball. In non-pilot speak: we stay coordinated. When used together, yaw and roll turn the airplane.
Sometimes if the turn is sharp enough, pilots need to raise the nose so we don't lose altitude. By pulling back on the stick, we move the elevators on the tail to the up position, forcing the tail down. The nose pitches up, and we crank around the turn.
SURFBOARDS
On a surfboard, our arms and shoulders act like the rudders. We look in the direction we want to go, reach with our "inside arm," turn our shoulders, and tell the
surfboard which way to go. It is a
subtle shift in weight. With the
help of our hips, the surfboard yaws about.
Our toes act as right ailerons. Our heels act as left ailerons. While pilots bank the airplane's wings, we bank the surfboard's rails by redistributing our weight. We dig our toes or press our heels. The surfboard rolls, dipping a rail in the wave.
If we want to trim or make a shallow turn, we apply more weight on our front foot, bringing the nose down. But if we want to turn hard and carve, we apply back foot pressure on our tail, the surfer's elevator control. The surfboard pitches up, and we carve out a front side bottom turn.
So, the next time you're out practicing trimming and carving in the waves, think about your body as control surfaces—arms (rudders), toes (ailerons), back foot (elevator)—and yaw, roll, and pitch your weight about.
The physics behind how we control yaw, roll, and pitch on a surfboard and in an airplane comes down to the same fact: It has a lot to do with our weight distribution. In a nutshell, surfers and pilots throw their weight around.
Bob McTavish, surfboard designer and leader in the shortboard revolution, said, "When you're designing a surfboard, you think, 'How can I help this board to rotate on this axis or all three?' It works just like an aircraft. But aircraft work in a constant static air fluid mass—we work in a constantly changing rotating plane of water—so interesting!" Surfboard designers, like McTavish, adjust how their boards rotate around the center of gravity, and so do aircraft designers.
Waves:
A Pilot's View
a Surfer's
yaw roll & Pitch