Last May, pilot Aaron Fitzgerald stunned onlookers as he performed flips, barrel rolls, and nosedives in his helicopter over New York Harbor. He was practicing stunts he planned to show off at a nearby air show.
As a helicopter’s blades turn, they create upward lift that keeps the aircraft aloft. Normally, a helicopter’s blades attach to a spinning rotor via flexible hinges. The hinges help the blades move with the airflow, allowing for a smoother ride. The blades of Fitzgerald’s special aerobatic helicopter, though, attach directly to its rotor. Because the blades don’t bend, the helicopter experiences more turbulence. But the rigid blades also allow the pilot to execute more-precise movements.
“The helicopter is harder to control, but it is very responsive, so it can make quick maneuvers,” explains Sertac Karaman, an aerospace roboticist at the Massachusetts Institute of Technology. That includes flipping the helicopter upside down!