Introduction to How Black Hawk Helicopters Work

As the twin engines of the Black Hawk roar for a new mission, the powerful blades sweep through the air creating a cloud of dust and dirt. Within minutes, the pilot has the chopper rising thousands of feet in the air and racing at 150 miles per hour over the landscape of a foreign land. Today's mission is to pass over enemy territory and deliver an 11-team crew to a strategic location on the battlefield.
 

 


Photo courtesy Department of Defense - Defense Visual Information Center
An HH-60H Sea Hawk flies a training mission over the Persian Gulf during Operation Southern Watch in 2000.  See more
pictures of Black Hawk helicopters.

 

 

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The Black Hawk UH-60L helicopter has been a mainstay of American armed forces since it entered service in 1978. Its flexible configuration, survivability, and maneuverability make it the medium utility helicopter of choice by military forces around the world. The UH-60L and its derivatives have amassed more than 5 million flight hours, including casualty evacuations, troop transports, and search-and-rescue missions.

In this article, you'll learn about the Black Hawk helicopter. We're going to focus on the UH-60L Black Hawk, describing its ability to fly, its use in combat operations, its development and its future prospects.

 

 

 

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.

 

 

Maneuverability

In addition to controlling the disc rotation, the pilot can further increase lift by adjusting the swash plate assembly. This mechanism is a combination of two plates -- one fixed and one rotating -- that are attached to the main rotor. These plates control each blade's pitch, or angle of attack. A change in each blade's pitch creates uneven lift, allowing the helicopter to tilt and fly in a particular direction.

Torque created by blade rotation is exerted on the helicopter's fuselage, which will spin in a counter direction unless it's neutralized. A tail rotor, which is attached to the tail boom, is how most helicopters counteract the torque created by the main rotor. The tail rotor of a Black Hawk has an 11-foot (3.35-m) blade that spins to create lateral force and stabilize the helicopter. By adjusting the pitch of the tail rotor, the pilot can turn the helicopter left or right.

 


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

Its power and maneuverability allow the Black Hawk to move soldiers quickly to strategic locations on the battlefield, and just as quickly get those soldiers back to safety. In the next section, you will learn more about how the Black Hawk is used to transport soldiers, artillery, and other equipment, and more about the built-in safety features that help the chopper survive if it comes under attack.

On the next page, you'll find out about the specifications of a UH-60L Black Hawk.

 

 

UH-60L Black Hawk Specifications

  • Length (with rotors turning): 64 feet, 10 inches (19.76 m)
  • Fuselage length: 50 feet, 0.75 inches (15.26 m)
  • Fuselage width: 7 feet, 9 inches (2.36 m)
  • Height: 16 feet, 10 inches (5.13 m)
  • Main rotor diameter: 53 feet, 8 inches (16.36 m)
  • Tail rotor diameter: 11 feet (3.35 m)
  • Cabin Dimensions: Length: 12 feet, 7 inches (3.84 m); Width: 6 feet, 2 inches (1.88 m); Height: 4 feet, 6 inches (1.37 m)
  • Weight (empty): 11,605 pounds (5,263 kg)
  • Mission gross weight: 17,527 pounds (7,950 kg)
  • Maximum cruise speed: 155 knots (178 mph, 287 km/h)
  • Never-exceed speed: 195 knots (225 mph, 361 km/h)
  • Vertical climb rate (at sea level): 3,000 feet (915 m)/minute
  • Service ceiling: 19,150 feet (5,837 m)
  • Range: 373 miles (600 km)
  • Unit cost: $5.9 million
Source: Brassey's World Aircraft & Systems Directory, Naval Air Warfare Center Aircraft Division

Now let's take a look at how the Black Hawk is used in combat situations.