Wednesday, July 22, 2009

Aerospatiale / Eurocopter HH-65 Dolphin


The HH-65 Dolphin search and rescue helicopter is solely in service with the United States Coast Guard.

The HH-65 Dolphin replaced the Sikorsky HH-52A Sea Guards then in service with the United States Coast Guard (USCG). The HH-65 is based on the French-made Eurocopter Dauphin (AS 365N) and carries the same - albeit translated - naming designation and primarily serves as a dedicated rescue helicopter noted by its formal classification of Short Range Recovery (SRR) helicopter. Despite its origins in the French-made Aerospatiale/Eurocopter system, the HH-65 Dolphin is produced in the United States by American Eurocopter, Textron Lycoming (turboshaft engines) and Rockwell Collins (electronics). First flight was achieved in 1980 and the system was introduce in whole by 1985. It maintains an active service standing in the USCG with some 102 total Dolphins making up the Coast Guard HH-65 force.

Design-wise, the HH-65 shares many of the same characteristics of her French-sister, the Eurocopter Dauphin. Her design in characterized by her low-set forward cockpit showcasing a smallish pointed nose assembly and a shrouded Fenestron tail section. The undercarriage is fully retractable and is made up of two single-wheeled main landing gears and a double-wheeled nose gear. Engines are mounted hit and above the crew cabin about midway on the design. The body integrates smoothly into a finely contoured empennage that fits a single vertical tail fin (above the Fenestron shroud) and a horizontal tailpane situated.

Power is derived from twin Turbomeca Arriel 2C2-CG turboshaft engines delivering up to 934 shaft horsepower and driving a corrosion-resistant composite four-bladed main rotor. Maximum speed tops 184 miles per hour with a range of 409 miles and a service ceiling of 15,000 feet. The Dolphin sports an empty weight of approximately 6,333lbs and a maximum take-off weight of up to 9,480lbs. Like the main rotor blades, the fuselage and rotor head are both constructed of corrosion-resistant materials for operations over the salty ocean. In fact, this type of composite construction makes up some 75% of the helicopter design.

Crew accommodations onboard a typical HH-65 model include the pilot, co-pilot, flight mechanic/flight engineer and rescue swimmer. Visibility is rated an excellent thanks to heavy use of glazing in the forward, side and top portions of the cockpit. The flight mechanic is afforded a chair which can slide on rails from one cabin side to the other as needed. The original Dolphin paint design featured a red, white and black scheme but this has since been changed to an overall red (still maintaining the black nose and exhaust sections) for easy visual marking from icebreaker vessels. The change in color has also cut off three days to the overhaul time needed for the aircraft.

The Dolphin maintains a distinct operating capability that allows its autopilot system to bring the aircraft to a hover or fly a designated flight pattern without the need for pilot intervention. This obviously frees up the pilots to other mission matters, particularly when having to visibly scan the surface of the ocean for persons or vessels. Deployment for Dolphins usually originates at land bases but Coast Guard Cutters are designed to take on the type.

The HH-65 has since been spawned into four major versions. The initial production model entered service in 1985 as the HH-65A, fitting twin LTS101-750B-2 series turboshaft engines of 735 shaft horsepower each. This was followed in 2001 by the upgraded HH-65B model with its revised avionics suite, twin global positioning integrated systems and two cockpit-mounted multi-function flat displays. If there was a drawback to the Dolphin system up to now, it lay in her Lycoming-brand engines, forcing the USCG to look through other powerplant options available.

The HH-65C's were essentially A and B production models fitted with twin the French-made Turbomeca Arriel 2C2-CG turboshaft engines of 934 shaft horsepower each. These powerplants were already proven components of the Eurocopter EC155 series and marked an improvement in both efficiency and reliability over the original set of American-made Lycoming (now Honeywell) LTS101-750B-2 turboshafts. Other changes to this model included new gearboxes for main rotor and tail, an 11-blade Fenestron tail rotor, an increase to its MTOW (Maximum Take-Off Weight) and a lengthened nose of new equipment. The first post-conversion C-models were made available in late 2004. A- and B-model Dolphins were retrofitted with the new Turbomeca Arriel 2C2-CG turboshafts and brought up to C-model standard, taking on the designation of HH-65C as well.

The MH-65C is a derivative of the HH-61C with an improved transmission, digital autopilot, revised avionics, increase fuel capacity, increased MTOW and a new 10-bladed tail rotor featuring noise reduction. The MH-65C has been used by the US Coast Guard's Helicopter Interdiction Tactical Squadron (HITRON) "Force from Above" armed helicopters. Based out of Jacksonville and operating with the Department of Homeland Security, these Dolphins are armed aircraft charged with conducting "Airborne Use of Force" sorties in high drug trafficking areas as well as to counter general security threats in American waters. To compliment this new-found role, the MH-65C's utilized by HITRON field a 7.62mm M240B general purpose machine gun and a 12.7mm Barrett M107CQ anti-materiel rifle. HITRON Dolphins are also used to guide their accompanying "Over The Horizon Cutter Boats" (OTHCB) to the scene of a given crime for possible interception and/or apprehension. MH-65C "HITRON" Dolphins began operations in 2008.

Other Dolphin mission parameters include working in conjunction with icebreakers, environmental management and special passenger transport.

As of this writing, the United States Coast Guard is the sole operator of the HH-65 Dolphin series. HH-65's are stationed in Alabama, New Jersey, Hawaii, Puerto Rico, Texas, California, Alaska, Louisiana, Oregon, Washington, Georgia, Michigan and Florida covering some 17 total cities within these states. The HH-65 Dolphin is one of the few American operational helicopters to make use of the French-designed Fenestron shrouded tail rotors. This shrouded style of tail rotor is proven to provide better stability when encountering crosswinds while using less power when in a hover. On the other hand, Fenestron tail rotors have proven expensive and heavier than traditional open-mounts while at the same time using more fuel.

Due to its high use of composite materials throughout its construction, the HH-65 sometimes takes on the nicknames of "Tupperwolf" or "Plastic Puppy".

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