section_path: Design
section_name: Design
paragraph_text: Design
  
  The UH-60 features four-blade main and tail rotors, and is powered by two General Electric T700 turboshaft engines. The main rotor is fully articulated and has elastomeric bearings in the rotor head. The tail rotor is canted and features a rigid crossbeam. The helicopter has a long, low profile shape to meet the Army's requirement for transporting aboard a C-130 Hercules, with some disassembly. It can carry 11 troops with equipment, lift 2,600 pounds (1,200 kg) of cargo internally or 9,000 pounds (4,100 kg) of cargo (for UH-60L/M) externally by sling.
  
  The Black Hawk helicopter series can perform a wide array of missions, including the tactical transport of troops, electronic warfare, and aeromedical evacuation. A VIP version known as the VH-60N is used to transport important government officials (e.g., Congress, Executive departments) with the helicopter's call sign of " Marine One " when transporting the President of the United States. In air assault operations, it can move a squad of 11 combat troops or reposition a 105 mm M119 howitzer with 30 rounds ammunition and a four-man crew in a single lift. The Black Hawk is equipped with advanced avionics and electronics for increased survivability and capability, such as the Global Positioning System.
  
  The UH-60 can be equipped with stub wings at the top of the fuselage to carry fuel tanks or various armaments. The initial stub wing system is called External Stores Support System (ESSS). It has two pylons on each wing to carry two 230 US gal (870 L) and two 450 US gal (1,700 L) tanks in total. The four fuel tanks and associated lines and valves form the external extended range fuel system (ERFS). U.S. Army UH-60s have had their ESSS modified into the crashworthy external fuel system (CEFS) configuration, replacing the older tanks with up to four total 200 US gal (760 L) crashworthy tanks along with self-sealing fuel lines. The ESSS can also carry 10,000 lb (4,500 kg) of armament such as rockets, missiles and gun pods. The ESSS entered service in 1986. However, it was found that the four fuel tanks obstruct the field of fire for the door guns; thus, the external tank system (ETS), carrying two fuel tanks on the stub wings, was developed.
  
  The unit cost of the H-60 models varies due to differences in specifications, equipment and quantities. For example, the unit cost of the Army's UH-60L Black Hawk is $5.9 million while the Air Force HH-60G Pave Hawk has a unit cost of $10.2 million.