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Sikorsky "Black Hawk" UH-60 - 40 years of service

14 Aug 2018

In the late 1960s, the United States Army began forming requirements for a helicopter to replace the UH-1 Iroquois, and designated the program as the Utility Tactical Transport Aircraft System (UTTAS). The Army also initiated the development of a new, common turbine engine for its helicopters that would become the General Electric T700. Based on experience in Vietnam, the Army required significant performance, survivability and reliability improvements from both UTTAS and the new power-plant. The Army released its UTTAS request for proposals in January 1972. The RFP also included air transport requirements. Transport aboard the C-130 limited the UTTAS cabin height and length.

 

UH-1 Iroquois

The UTTAS requirements for improved reliability, survivability and lower life-cycle costs resulted in features such as dual-engines with improved hot and high altitude performance, and a modular design (reduced maintenance footprint); run-dry gearboxes; ballistically tolerant, redundant subsystems (hydraulic, electrical and flight controls); crashworthy crew  and troop seats; dual-stage oleo main landing gear; ballistically tolerant, crashworthy main structure; quieter, more robust main and tail rotor systems; and a ballistically tolerant, crashworthy fuel system.

 

Four prototypes were constructed, with the first YUH-60A flying on 17 October 1974. Prior to delivery of the prototypes to the US Army, a preliminary evaluation was conducted in November 1975 to ensure the aircraft could be operated safely during all testing. Three of the prototypes were delivered to the Army in March 1976, for evaluation against the rival Boeing-Vertol design, the YUH-61A, and one was kept by Sikorsky for internal research. The Army selected the UH-60 for production in December 1976. Deliveries of the UH-60A to the Army began in October 1978 and the helicopter entered service in June 1979.

 First Flight of the YUH-60A

After entering service, the helicopter was modified for new missions and roles, including mine laying and medical evacuation. An EH-60 variant was developed to conduct electronic warfare and special operations.

Medical Evacuation

Due to weight increases from the addition of mission equipment and other changes, the Army ordered the improved UH-60L in 1987. The new model incorporated all of the modifications made to the UH-60A fleet as standard design features. The UH-60L also featured more power and lifting capability with upgraded T700-GE-701C engines and a stronger gearbox, both developed for the SH-60B Sea-hawk.  Its external lift capacity increased by 1,000 lb (450 kg) up to 9,000 lb (4,100 kg). The UH-60L also incorporated the automatic flight control system (AFCS) from the SH-60 for better flight control due to handling issues with the more powerful engines. Production of the L-model began in 1989.

T700-GE-701C

SH-60B Sea-hawk 

Development of the next improved variant, the UH-60M, was approved in 2001, to extend the service life of the UH-60 design into the 2020s. The UH-60M incorporates upgraded T700-GE-701D engines, improved rotor blades, and state of the art electronic instrumentation, flight controls and aircraft navigation control. After the U.S. DoD approved low-rate initial production of the new variant, manufacturing began in 2006, with the first of 22 new UH-60Ms delivered in July 2006. After an initial operational evaluation, the Army approved full-rate production and a five-year contract for 1,227 helicopters in December 2007. By March 2009, 100 UH-60M helicopters had been delivered to the Army. In November 2014, US military ordered 102 aircraft of various H-60 types, worth $1.3 billion.

UH-60M

Following an operation in May 2011, it emerged that the 160th SOAR used a secret version of the UH-60 modified with low-observable technology which enabled it to evade Pakistani radar. Analysis of the tail section, the only remaining part of the aircraft which crashed during the operation, revealed extra blades on the tail rotor and other noise reduction measures, making the craft much quieter than conventional UH-60s. The aircraft appeared to include features like special high-tech materials, harsh angles, and flat surfaces found only in stealth jets. Low observable versions of the Black Hawk have been studied as far back as the mid-1970s.

SOAR Stealth UH-60

In September 2012, Sikorsky was awarded a Combat Tempered Platform Demonstration (CTPD) contract to further improve the Black Hawk's durability and survivability. The company is to develop new technologies such as a zero-vibration system, adaptive flight control laws, advanced fire management, a more durable main rotor, full-spectrum crashworthiness, and damage tolerant airframe; then they are to transition them to the helicopter. Improvements to the Black Hawk are to continue until the Future Vertical Lift program is ready to replace it.

 

In December 2014, the 101st Airborne Division began testing of new resupply equipment called the Enhanced Speed Bag System (ESBS). Soldiers pinned down in the field requiring quick resupply have depended on speed bags, bags filled with items airdropped from a UH-60. However, all systems were ad-hoc with bags not made to keep things secure from impacts, so up to half of the airdropped items would be damaged upon hitting the ground. Started in 2011, the ESBS sought to standardize the airdrop resupply method and keep up to 90 percent of supplies intact. The system includes a hands-free reusable linear brake and expendable speed line and multipurpose cargo bag; when the bag is deployed, the brake applies friction to the rope, slowing it down enough to keep the bag oriented down on the padded base, a honeycomb and foam kit inside to dissipate energy. The ESBS not only better protects helicopter-dropped supplies, it allows the Black Hawk to fly higher above the ground, 100 ft (30 m) up from 10 feet, while traveling 20 knots (23 mph; 37 km/h), limiting exposure to ground fire. Each bag can weigh 125–200 lb (57–91 kg) and up to six can be deployed at once, dropping 40–50 feet per second (12–15 m/s). Since supplies can be delivered more accurately and the system can be automatically released on its own, the ESBS can enable autonomous resupply from unmanned helicopters.

Enhanced Speed Bag System

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.

Marine One

The UH-60 can be equipped with stub wings at the top of 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.

UH-60 External Stores Support System

Mark Jackson, owner of the locally based company Leading Edge Aviation, at Nelspruit Airfield, bought a Black Hawk and started the long process of importing it to South Africa in 2016. In October 2017 South Africa’s first-ever Black Hawk was successfully imported, making it only the second one in history to enter civilian service outside the United States at the time. This 1980 Black Hawk was assembled and painted at Leading Edge Aviation.

In 2016 Peter Jackson and Tosh Ross underwent specialised flight training in Montana to enable them to pilot this machine. The Black Hawk is now permanently stationed at  Kishugu Aviation alongside many Bell UH-1 “Hueys”  to ensure aerial firefighting is done even more effectively in South Africa. “The Black Hawk will complement our firefighting fleet, such as the “Hueys”, that we are currently using in firefighting operations. It can reach speeds of up to 300 kilometres per hour and lift three tons of water per drop, where the “Hueys” are currently doing one ton,” Mark Jackson said at the first flight of this remarkable machine.

 

 

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