Army researchers invented a hinge that improves how quickly a quadrotor the size of a king-sized mattress can ascend from the ground to the rooftop of a two-story building, particularly with large payloads. The hinge is located at the root of the quadrotor blade next to the hub so that the blade pitch changes with rotor speed.
As quadrotors and similar aircraft are scaled up, the extra inertia of the rotor blade slows them down. With the new coupling, the thrust becomes more sensitive to changes in rotation per minute (RPM). Large quadrotors carrying these loads could climb roughly 25 feet in as little as two seconds with the hinge, instead of three or four seconds without it.