Power and Flight

Photo courtesy Department of Defense - Defense Visual Information Center UH-60A Black Hawks transport ground forces during a riot control exercise.

A Black Hawk takes to the air like any other helicopter. Flight is achieved when the helicopter engines turn the tilted blades fast enough to generate lift. Lift is generated as the angled blades spin through the air. The blade rotation causes the air above the blades to move faster than the air below them, which creates pressure. Once that pressure under the blades is higher than the pressure above the blades, the helicopter lifts off the ground. To learn more about lift, read How Airplanes Work.

Two General Electric T700-GE-701C turboshaft engines turn the drive shaft. The drive shaft extends to the top of the helicopter, where it connects to the rotor head, which is comprised of the rotor hub and four rotor blades. Each blade consists of a titanium spar, which is a metal strip that runs from the base of the blade to its tip, and a Nomex honeycomb material.

Photo courtesy Department of Defense - Defense Visual Information Center Soldiers perform a check of the top rotor on the UH-60 Black hawk on the ramp.

Photo courtesy Department of Defense - Defense Visual Information Center A soldier performs a maintenance check on the top rotor of a UH-60 Black Hawk.

The blade skin and trailing edge are made of composite materials. The stronger, leading edge of the blade is made of titanium and nickel and is trimmed with an anti-erosion strip, which protects the blade from wear as it skims across the tree tops or flies in abrasive desert air.

As the drive shaft turns the rotor head, the blades begin to spin. As the blades cut through the air, they create the rotor disc, which is the circle created as the blades spin. The diameter of the Black Hawk's rotor disc is 53 feet, 8 inches (16.36 m). Larger helicopters or helicopters that carry heavy loads, such as the Black Hawk, require a large rotor disc. The disc rotation of the Black Hawk generates enough force to lift the vehicle with crew, troops, and as much as a 9,000-pound (4,082.33-kg) external payload.