Like the name suggests, this tricky stunt involves completion of nine maneuvers in succession to get to 1,800 degrees. This involves four corks (off-axis flips) and five complete spins. A cork is a spin that rotates up/down and left/right. To the untrained eye, a quad cork 1800 just looks like a bunch of whirls and spins. However, the physics behind this seemingly crazy trick are quite intriguing.
While all phases are important to complete the quad cork 1800, the launch sets the stage because speed allows you to get enough height to complete the flips. Morgan usually needs about 40 mph at takeoff to complete this trick. He then initiates the spin by performing a simultaneous abdominal crunch and trunk twist. To put this into perspective: It takes approximately 50 foot-pounds of torque to generate this quick effort. Turning your head only takes 0.05 foot-pounds.
Once the spin has initiated, the athlete crouches down and grasps the board while spiraling through the air. This tuck reduces the instant of inertia. Keep in mind that tighter tucks create faster rotations. You have to use your left arm to regulate the direction of the rotation throughout the first cork.
In order to continue the maneuver, it takes speed. This is gained by pulling both arms tightly against the chest. Ideally, you’re looking for 1.7 revolutions per second. The high speed is necessary in order to finish the five rotations.
The preparation for the impact of the landing starts during the last cork. This involves slowing down the rotation by straightening the body and placing the arms straight out. During the landing, you’re still hitting the ground at about 50 mph. On each leg, you’ll experience 450 pounds of force while trying to stick the landing.
Ideally, you should land at an angle that allows for gradual deceleration. Morgan chooses 14 degrees and bends his knees to distribute forces. This also helps prevent a collision with the wall. All in all, the whole trick can take less than 3 seconds and reaches heights of over 130 feet.