Welcome to flightglobal. This website uses cookies to improve your experience. By continuing to browse this site you are agreeing to our use of these cookies. You can learn more about the cookies we use here. But can modernisation be done on time and within budget? Helicopter remanufacturing in recent years has gained something of a reputation within the US Department of Defense for producing unpleasant surprises in terms of cost growth and development slippages.
The US Army and Sikorsky are hoping to put the record straight with one of the largest remanufacturing programmes undertaken to date to modernise more than 1, UH Black Hawks over the course of the next 20 years. The UHM programme is intended to give the army's utility helicopter fleet a new lease of life, adding capability while achieving a significant cut in operating and support costs. The key to doing this successfully is to keep the cost of remanufacturing competitively priced, something the US Navy failed to achieve with the SHR Seahawk programme.
It subsequently abandoned remanufacturing in favour of all-new MHR airframes. We're getting new cabins, refurbished cockpits and tails, new black boxes, upgraded engines and transmissions. We're attacking all the things that need to be attacked. The UHM programme is subdivided into three major areas focusing on the helicopter's structure, powerplant and dynamic components and avionics systems.
The modernisation process will induct a mixed fleet of UHAs, and more powerful UHLs, UHQ and HHL medical evacuation medevac variants and turn out a commonly configured fleet of 1, UHMs, of which about one in four will be equipped for the medevac mission.
Troy, Alabama-based Sikorsky Support Services will be the initial recipient, tasked with assessing and disassembling each helicopter.
Of the major structural components, the cockpit, tailcone and tailrotor pylon will be refurbished and shipped to Sikorsky's main Stratford plant for re-assembly and joining with new-build cabin sections and horizontal stabilisers.
The decision to build all-new cabins was driven by the fact that the dynamic and external-stores load bearing mid-section represents the critical path in terms of the Black Hawk's 8,h airframe fatigue life. High-speed machining has allowed for a significant reduction in the structural parts count. Examples include the Stage lower frame assembly, which now totals five parts and 56 fasteners compared with five times that number on the UHL, integral wiring clip provisions on virtually every tub frame and a single-piece design external-stores support system.
Plans to shift to die forging promises to further reduce machine parts in the future, including possibly rivetless butt line beams. A folding horizontal stabiliser is being added for better transportability, and may be constructed in composite material if a new Israel Aircraft Industries design is adopted.
Sikorsky is aiming for a 7kg 15lb weight saving on the current aluminium design to improve centre of gravity. This reduces weight by a further 20kg and is being looked at for the UHM in the longer term. Force generators of the AVCS could be located wherever necessary throughout the fuselage to generate forces so as to cancel out local vibrations.
The heart of the system was a closed-loop algorithm that calculated the force generator commands required to minimize vibrations as measured by accelerometers located throughout the cockpit and cabin. A feedback control algorithm processed a tachometer signal, providing frequency and phase information, and also processed accelerometer signals that feed back local vibration conditions.
The AVCS computer calculated the required force generator commands and sent them digitally to an electronic unit. This unit then converted the digital signals to analog signals, which then were sent to electric motors within the force generators. These motors drove counter-rotating eccentric masses to generate forces of appropriate magnitude and frequency to cancel fuselage vibrations. In the UHM, a force generator capable of producing lb. In addition, generators able to produce lb.
Digital Avionics and Integrated Displays All key aspects of the UHM cockpit were brought up to latest military aviation standards regarding display technology, digital avionics, digital flight control components and modular open architecture systems. Its new cockpit incorporated dual digital data busses and advances in digital avionics architecture together with a much improved flight control system. Four-color multi-function displays MFDs were used in the new cockpit designed to increase pilot situational awareness and interoperability with joint forces on and in the battlefield area.
Digitized features and equipment assured more precise long-range navigation, command and control interoperability and were compatible with future air traffic management requirements. The new cockpit incorporated an improved message and data transfer capability as well as dual embedded global positioning and inertial navigation systems. Dual digital computer flight control computers were installed, along with a fully coupled flight director system, providing stability augmentation, trim and flight path stabilization functions.
A major benefit of the new control system and the integrated displays was the ability to conduct combat operations during degraded visual conditions with more precision and safety. The redesigned and smaller instrument panel containing the four MFDs all of which were 6 X 8 inch active matrix liquid crystal displays are shown in the illustration below. They provided primary flight, navigation and tactical information and they were fully integrated with a digital moving map displaying real-time aircraft position and terrain information, a Stormscope for detecting lightning activity, and a radar warning system.
Four multi-function displays with a shortened instrument panel provided greater visibility of terrain and ground personnel. Two control display units were installed in the center console. The cockpit arrangement and displays shown are typical of earlier UH A and L versions that were based on conventional analog instruments as well as non-integrated avionic units.
Mission Systems The major cockpit upgrade of the Mike model provided the capability to achieve standardization of equipment and training across Black Hawk derivative models as well as with other Army helicopters.
Four color multi-function displays MFDs were installed to increase pilot situational awareness and interoperability with joint forces on and in the battlefield area. Digitized features and equipment assure more precise long-range navigation, command and control interoperability and are compatible with future air traffic management requirements. The SA can carry external loads up to 9,lb 4,kg on the cargo hook, for example, a mm howitzer.
The main cabin can be cleared of troop seats for transportation of cargo. Additional stores can be carried on the external stores support system.
The SA is equipped with a voice and data communications suite including VHF, UHF communications, an identification friend or foe IFF transponder, secure voice communications, satellite communications and an intercom system. US Army Blackhawks are being fitted with the latest version, the D, which is rated at 2,shp. The internal fuel tanks have a capacity of 1,l. Auxiliary fuel can be carried with 1,l in two internal fuel tanks and 1,l externally.
The first aircraft was delivered to the US Army in September and another seven by December The final two helicopters will be delivered by end of September The contract also includes an option for ten additional aircraft.
The five-year contract also includes an option to acquire additional aircraft. The government is expected to float a tender for this purpose towards the end of , with final contract award in late Sikorsky plans to offer Si aircraft built in Poland under the contract. Type Medium-lift multi-mission helicopter.
SA Black Hawk can be armed with missiles, rockets, machine guns and 20mm cannons.
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