UH-60 Black Hawk utility tactical transport helicopter
Development of UH-60
The development of UH-60 Black Hawk started in January 1972 as the part of Utility Tactical Transport Aircraft System (UTTAS) program. Helicopter manufacturers were asked to submit proposals for a new machine that would carry heavier loads at greater speeds and over greater distances than the Bell UH-1 Huey. At the same time, the design was to provide better protection and durability than the earlier helicopter.
Several companies offered proposals. The two finalists in the competition were Boeing Vertol and Sikorsky. Both were asked to build five prototypes, three of which were to be flying examples and two that were to be used for ground testing. Sikorsky had already started a series of experiments to look for possible technologies that would be of use in the new helicopter, using modified S-61 and S-65 transport helicopters, and the company had also begun development of a gunship helicopter, the S-67.
Using the lessons learned from these experimental programs, Sikorsky developed a design that was given the company designation S-70. Boeing Vertol’s competing design, which was to have a composite main rotor, was the Model 237. The two designs were given the military designations YUH-60A and YUH-61A respectively. Both were to be powered by twin General Electric T700 engines. The UH-60A prototype first flew on October 17, 1974, with the YUH-61A following six weeks later on November 29.
The new helicopter was going to be extremely important to the US Army, so the evaluation program that began in 1976 was exceptionally thorough. The Sikorsky machine demonstrated the toughness and survivability that was a particularly important Army requirement when one of the prototypes crash-landed while on trials. On earlier designs, the chances were that the crew would have been seriously injured, but they survived this crash unharmed. The Army was also impressed by the fact that the machine flew from the crash site under its own power once its rotor blades had been replaced.
Sikorsky won UTTAS and replace UH-1 Huey
On December 23, 1976, the Army announced that Sikorsky had won the UTTAS competition. An initial contract was issued for three preproduction aircraft and 15 production UH-60As, and the new type was given the name Black Hawk. The first production helicopter flew in October 1978, and it entered operational service with the 101st Air Assault Division in summer 1979. The type’s combat debut came in Grenada in 1983, where it proved as resistant to battle damage as the Army had hoped. In one incident, a flight of Black Hawks came under fierce machine-gun and cannon fire from the ground, surviving an antiaircraft fire onslaught which would probably have destroyed a flight comprising Bell UH-1 Hueys.
Faster, tougher, and much more capable than the UH-1 it replaced, the UH-60 Black Hawk is now the US Army’s most important utility transport helicopter. It provides the bulk of vertical troop-lift capability for Army divisions of all types. The UH-60A is of conventional design with a large four-bladed main rotor, and a small four-bladed tail rotor. A combined tailplane and elevator, known as a stabilator, was mounted high on the tail fin in early prototypes, but was moved to the base of the fin in production aircraft. The main rotor blades are very tough, which enables them to survive hits from explosive cannon rounds. The strength comes from the use of composite and glass-reinforced plastic materials wrapped round a titanium spar, and to protect against damage from branches, the leading edge is sheathed with nickel. The composite tail rotor is tilted 20 degrees from the vertical, partly to reduce the noise it generates.
The initial prototype differed from production machines in having a fixed swept stabilator, which tended to cause the helicopter to nose up and led to a series of experiments for alternate configurations. It was also fitted with a retractable tail wheel, and had a different fuselage and engine exhaust configuration.
Modern weaponry needs to be transported by air to allow for rapid deployment around the world. A feature of the original UTTAS requirement was that the new helicopter should be able to fit into standard USAF transport aircraft with a minimum of disassembly. The long, low design of the UH-60 and the low-set main rotor allow the helicopter to fit into the cargo bay of a Lockheed C-130 Hercules simply by folding its rotor blades. The C-130 can carry one Black Hawk, the Lockheed C-141B Starlifter can carry two, and the Lockheed C-5 Galaxy can carry six. The Starlifter has been replaced by the Boeing C-17 Globemaster II, a much larger aircraft with the capacity to carry three or four UH-60 Black Hawks.
UH-60 Engines and Performance
The UH-60A is powered by twin General Electric T700-GL-700 turboshaft engines. These are designed to provide 1,560 shp each. Like the rest of the Black Hawk, the engines are incredibly tough. They are designed to operate for at least 30 minutes, even after suffering battle damage sufficient to drain all of the engine oil. To start the main engines and for providing power on the ground, a T62T-40-1 auxiliary power unit (AFU) able to deliver 100 shp is mounted between the main engines. As a further exercise in strengthening, the fuel tanks are armored against small-arms fire and are also crash-resistant. Maximum speed is 163 mph, though the normal operating maximum is 145 mph. Maximum range with standard fuel and with no reserves is about 365 miles.
The UH-60A Black Hawk has wheeled landing gear, featuring heavy-duty shock absorbers designed to take up the impact of a hard landing without causing damage. The three wheels are in tail dragger configuration, with two at the front and one at the rear of fuselage. The helicopter can also be fitted with wide ski-style pads, enabling the machine to operate from swampy ground or from snow and ice.
The UH-60A carries a crew of three, including two pilots and a crew chief/gunner, all of whom are provided with armored seats resistant to 23 mm cannon fire. Normal passenger capacity is for 11 fully equipped infantrymen, though in an emergency the Black Hawk can carry up to 20 passengers. By removing eight troop seats, the helicopter can be configured to carry four litters in the medical evacuation (MEDEVAC) role. The cabin is fitted with sliding doors on both sides.
External loads can also be carried: the UH-60A has a belly sling hook with a capacity of up to 8,000 lb. This is enough to enable the Black Hawk to lift a 105 mm artillery piece or a Hummer vehicle.
UH-60 Black Hawk Armament
For self-defense, a machine gun can be pintle-mounted in a slide-open window on each side of the helicopter just behind the cockpit. This helps reduce clutter in the doorways, reflecting combat experience with the Bell UH-1 when door guns obstructed troops trying to deploy under fire. Initially, M-60D 7,62mm machine guns on the M144 armament subsystem were mounted, but these were later replaced by General Electric M134 7.62mm six-barreled Gatling-type miniguns or by the M240 variant of the FN MAG machine gun. The helicopter can also carry the M130 general purpose dispenser, which deploys chaff and infrared jamming flares.
Standard UH-60 Black Hawks in US service have had very few color schemes applied in service, most being completed in Overall Helo Drab (Federal Standard paint 34031). This example is operated by the California Army National Guard, which has two companies of the 1st Battalion, 140th Aviation Regiment equipped with troop carrying UH-60A/Ls based at Los Alamitos. The 126th Medical Company (Air Ambulance) operates the same type of helicopter, as well as a number of HH-60Ls out of Mather Field. The California Guard units have deployed in support of regular army units to the Balkans, Iraq, and Afghanistan, as well as providing support for state authorities on lifesaving, search-and-rescue, and firefighting missions.
UH-60 Black Hawk Specification
Sikorsky Helicopters Official Website - http://www.sikorsky.com/Index
United States Marine Corps - http://www.marines.com/#default